1 /*-------------------------------------------------------------------------
4 * PostgreSQL transaction log manager
7 * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
12 *-------------------------------------------------------------------------
26 #include "access/clog.h"
27 #include "access/multixact.h"
28 #include "access/subtrans.h"
29 #include "access/transam.h"
30 #include "access/tuptoaster.h"
31 #include "access/twophase.h"
32 #include "access/xact.h"
33 #include "access/xlog_internal.h"
34 #include "access/xlogutils.h"
35 #include "catalog/catversion.h"
36 #include "catalog/pg_control.h"
37 #include "catalog/pg_type.h"
39 #include "libpq/pqsignal.h"
40 #include "miscadmin.h"
42 #include "postmaster/bgwriter.h"
43 #include "storage/bufmgr.h"
44 #include "storage/fd.h"
45 #include "storage/ipc.h"
46 #include "storage/pmsignal.h"
47 #include "storage/procarray.h"
48 #include "storage/smgr.h"
49 #include "storage/spin.h"
50 #include "utils/builtins.h"
51 #include "utils/flatfiles.h"
52 #include "utils/guc.h"
53 #include "utils/ps_status.h"
57 /* File path names (all relative to $PGDATA) */
58 #define BACKUP_LABEL_FILE "backup_label"
59 #define BACKUP_LABEL_OLD "backup_label.old"
60 #define RECOVERY_COMMAND_FILE "recovery.conf"
61 #define RECOVERY_COMMAND_DONE "recovery.done"
64 /* User-settable parameters */
65 int CheckPointSegments
= 3;
67 int XLogArchiveTimeout
= 0;
68 bool XLogArchiveMode
= false;
69 char *XLogArchiveCommand
= NULL
;
70 bool fullPageWrites
= true;
71 bool log_checkpoints
= false;
72 int sync_method
= DEFAULT_SYNC_METHOD
;
75 bool XLOG_DEBUG
= false;
79 * XLOGfileslop is the maximum number of preallocated future XLOG segments.
80 * When we are done with an old XLOG segment file, we will recycle it as a
81 * future XLOG segment as long as there aren't already XLOGfileslop future
82 * segments; else we'll delete it. This could be made a separate GUC
83 * variable, but at present I think it's sufficient to hardwire it as
84 * 2*CheckPointSegments+1. Under normal conditions, a checkpoint will free
85 * no more than 2*CheckPointSegments log segments, and we want to recycle all
86 * of them; the +1 allows boundary cases to happen without wasting a
87 * delete/create-segment cycle.
89 #define XLOGfileslop (2*CheckPointSegments + 1)
94 const struct config_enum_entry sync_method_options
[] = {
95 {"fsync", SYNC_METHOD_FSYNC
, false},
96 #ifdef HAVE_FSYNC_WRITETHROUGH
97 {"fsync_writethrough", SYNC_METHOD_FSYNC_WRITETHROUGH
, false},
100 {"fdatasync", SYNC_METHOD_FDATASYNC
, false},
102 #ifdef OPEN_SYNC_FLAG
103 {"open_sync", SYNC_METHOD_OPEN
, false},
105 #ifdef OPEN_DATASYNC_FLAG
106 {"open_datasync", SYNC_METHOD_OPEN_DSYNC
, false},
112 * Statistics for current checkpoint are collected in this global struct.
113 * Because only the background writer or a stand-alone backend can perform
114 * checkpoints, this will be unused in normal backends.
116 CheckpointStatsData CheckpointStats
;
119 * ThisTimeLineID will be same in all backends --- it identifies current
120 * WAL timeline for the database system.
122 TimeLineID ThisTimeLineID
= 0;
125 * Are we doing recovery from XLOG?
127 * This is only ever true in the startup process, even if the system is still
128 * in recovery. Prior to 8.4, all activity during recovery were carried out
129 * by Startup process. This local variable continues to be used in functions
130 * that need to act differently when called from a redo function (e.g skip
131 * WAL logging). To check whether the system is in recovery regardless of what
132 * process you're running in, use RecoveryInProgress().
134 bool InRecovery
= false;
136 /* Are we recovering using offline XLOG archives? */
137 static bool InArchiveRecovery
= false;
140 * Local copy of SharedRecoveryInProgress variable. True actually means "not
141 * known, need to check the shared state"
143 static bool LocalRecoveryInProgress
= true;
145 /* Was the last xlog file restored from archive, or local? */
146 static bool restoredFromArchive
= false;
148 /* options taken from recovery.conf */
149 static char *recoveryRestoreCommand
= NULL
;
150 static bool recoveryTarget
= false;
151 static bool recoveryTargetExact
= false;
152 static bool recoveryTargetInclusive
= true;
153 static TransactionId recoveryTargetXid
;
154 static TimestampTz recoveryTargetTime
;
155 static TimestampTz recoveryLastXTime
= 0;
157 /* if recoveryStopsHere returns true, it saves actual stop xid/time here */
158 static TransactionId recoveryStopXid
;
159 static TimestampTz recoveryStopTime
;
160 static bool recoveryStopAfter
;
163 * During normal operation, the only timeline we care about is ThisTimeLineID.
164 * During recovery, however, things are more complicated. To simplify life
165 * for rmgr code, we keep ThisTimeLineID set to the "current" timeline as we
166 * scan through the WAL history (that is, it is the line that was active when
167 * the currently-scanned WAL record was generated). We also need these
170 * recoveryTargetTLI: the desired timeline that we want to end in.
172 * expectedTLIs: an integer list of recoveryTargetTLI and the TLIs of
173 * its known parents, newest first (so recoveryTargetTLI is always the
174 * first list member). Only these TLIs are expected to be seen in the WAL
175 * segments we read, and indeed only these TLIs will be considered as
176 * candidate WAL files to open at all.
178 * curFileTLI: the TLI appearing in the name of the current input WAL file.
179 * (This is not necessarily the same as ThisTimeLineID, because we could
180 * be scanning data that was copied from an ancestor timeline when the current
181 * file was created.) During a sequential scan we do not allow this value
184 static TimeLineID recoveryTargetTLI
;
185 static List
*expectedTLIs
;
186 static TimeLineID curFileTLI
;
189 * ProcLastRecPtr points to the start of the last XLOG record inserted by the
190 * current backend. It is updated for all inserts. XactLastRecEnd points to
191 * end+1 of the last record, and is reset when we end a top-level transaction,
192 * or start a new one; so it can be used to tell if the current transaction has
193 * created any XLOG records.
195 static XLogRecPtr ProcLastRecPtr
= {0, 0};
197 XLogRecPtr XactLastRecEnd
= {0, 0};
200 * RedoRecPtr is this backend's local copy of the REDO record pointer
201 * (which is almost but not quite the same as a pointer to the most recent
202 * CHECKPOINT record). We update this from the shared-memory copy,
203 * XLogCtl->Insert.RedoRecPtr, whenever we can safely do so (ie, when we
204 * hold the Insert lock). See XLogInsert for details. We are also allowed
205 * to update from XLogCtl->Insert.RedoRecPtr if we hold the info_lck;
206 * see GetRedoRecPtr. A freshly spawned backend obtains the value during
209 static XLogRecPtr RedoRecPtr
;
212 * Shared-memory data structures for XLOG control
214 * LogwrtRqst indicates a byte position that we need to write and/or fsync
215 * the log up to (all records before that point must be written or fsynced).
216 * LogwrtResult indicates the byte positions we have already written/fsynced.
217 * These structs are identical but are declared separately to indicate their
218 * slightly different functions.
220 * We do a lot of pushups to minimize the amount of access to lockable
221 * shared memory values. There are actually three shared-memory copies of
222 * LogwrtResult, plus one unshared copy in each backend. Here's how it works:
223 * XLogCtl->LogwrtResult is protected by info_lck
224 * XLogCtl->Write.LogwrtResult is protected by WALWriteLock
225 * XLogCtl->Insert.LogwrtResult is protected by WALInsertLock
226 * One must hold the associated lock to read or write any of these, but
227 * of course no lock is needed to read/write the unshared LogwrtResult.
229 * XLogCtl->LogwrtResult and XLogCtl->Write.LogwrtResult are both "always
230 * right", since both are updated by a write or flush operation before
231 * it releases WALWriteLock. The point of keeping XLogCtl->Write.LogwrtResult
232 * is that it can be examined/modified by code that already holds WALWriteLock
233 * without needing to grab info_lck as well.
235 * XLogCtl->Insert.LogwrtResult may lag behind the reality of the other two,
236 * but is updated when convenient. Again, it exists for the convenience of
237 * code that is already holding WALInsertLock but not the other locks.
239 * The unshared LogwrtResult may lag behind any or all of these, and again
240 * is updated when convenient.
242 * The request bookkeeping is simpler: there is a shared XLogCtl->LogwrtRqst
243 * (protected by info_lck), but we don't need to cache any copies of it.
245 * Note that this all works because the request and result positions can only
246 * advance forward, never back up, and so we can easily determine which of two
247 * values is "more up to date".
249 * info_lck is only held long enough to read/update the protected variables,
250 * so it's a plain spinlock. The other locks are held longer (potentially
251 * over I/O operations), so we use LWLocks for them. These locks are:
253 * WALInsertLock: must be held to insert a record into the WAL buffers.
255 * WALWriteLock: must be held to write WAL buffers to disk (XLogWrite or
258 * ControlFileLock: must be held to read/update control file or create
261 * CheckpointLock: must be held to do a checkpoint or restartpoint (ensures
262 * only one checkpointer at a time)
267 typedef struct XLogwrtRqst
269 XLogRecPtr Write
; /* last byte + 1 to write out */
270 XLogRecPtr Flush
; /* last byte + 1 to flush */
273 typedef struct XLogwrtResult
275 XLogRecPtr Write
; /* last byte + 1 written out */
276 XLogRecPtr Flush
; /* last byte + 1 flushed */
280 * Shared state data for XLogInsert.
282 typedef struct XLogCtlInsert
284 XLogwrtResult LogwrtResult
; /* a recent value of LogwrtResult */
285 XLogRecPtr PrevRecord
; /* start of previously-inserted record */
286 int curridx
; /* current block index in cache */
287 XLogPageHeader currpage
; /* points to header of block in cache */
288 char *currpos
; /* current insertion point in cache */
289 XLogRecPtr RedoRecPtr
; /* current redo point for insertions */
290 bool forcePageWrites
; /* forcing full-page writes for PITR? */
294 * Shared state data for XLogWrite/XLogFlush.
296 typedef struct XLogCtlWrite
298 XLogwrtResult LogwrtResult
; /* current value of LogwrtResult */
299 int curridx
; /* cache index of next block to write */
300 pg_time_t lastSegSwitchTime
; /* time of last xlog segment switch */
304 * Total shared-memory state for XLOG.
306 typedef struct XLogCtlData
308 /* Protected by WALInsertLock: */
309 XLogCtlInsert Insert
;
311 /* Protected by info_lck: */
312 XLogwrtRqst LogwrtRqst
;
313 XLogwrtResult LogwrtResult
;
314 uint32 ckptXidEpoch
; /* nextXID & epoch of latest checkpoint */
315 TransactionId ckptXid
;
316 XLogRecPtr asyncCommitLSN
; /* LSN of newest async commit */
318 /* Protected by WALWriteLock: */
322 * These values do not change after startup, although the pointed-to pages
323 * and xlblocks values certainly do. Permission to read/write the pages
324 * and xlblocks values depends on WALInsertLock and WALWriteLock.
326 char *pages
; /* buffers for unwritten XLOG pages */
327 XLogRecPtr
*xlblocks
; /* 1st byte ptr-s + XLOG_BLCKSZ */
328 int XLogCacheBlck
; /* highest allocated xlog buffer index */
329 TimeLineID ThisTimeLineID
;
332 * SharedRecoveryInProgress indicates if we're still in crash or archive
333 * recovery. It's checked by RecoveryInProgress().
335 bool SharedRecoveryInProgress
;
338 * During recovery, we keep a copy of the latest checkpoint record
339 * here. Used by the background writer when it wants to create
342 * Protected by info_lck.
344 XLogRecPtr lastCheckPointRecPtr
;
345 CheckPoint lastCheckPoint
;
347 /* end+1 of the last record replayed (or being replayed) */
348 XLogRecPtr replayEndRecPtr
;
350 slock_t info_lck
; /* locks shared variables shown above */
353 static XLogCtlData
*XLogCtl
= NULL
;
356 * We maintain an image of pg_control in shared memory.
358 static ControlFileData
*ControlFile
= NULL
;
361 * Macros for managing XLogInsert state. In most cases, the calling routine
362 * has local copies of XLogCtl->Insert and/or XLogCtl->Insert->curridx,
363 * so these are passed as parameters instead of being fetched via XLogCtl.
366 /* Free space remaining in the current xlog page buffer */
367 #define INSERT_FREESPACE(Insert) \
368 (XLOG_BLCKSZ - ((Insert)->currpos - (char *) (Insert)->currpage))
370 /* Construct XLogRecPtr value for current insertion point */
371 #define INSERT_RECPTR(recptr,Insert,curridx) \
373 (recptr).xlogid = XLogCtl->xlblocks[curridx].xlogid, \
375 XLogCtl->xlblocks[curridx].xrecoff - INSERT_FREESPACE(Insert) \
378 #define PrevBufIdx(idx) \
379 (((idx) == 0) ? XLogCtl->XLogCacheBlck : ((idx) - 1))
381 #define NextBufIdx(idx) \
382 (((idx) == XLogCtl->XLogCacheBlck) ? 0 : ((idx) + 1))
385 * Private, possibly out-of-date copy of shared LogwrtResult.
386 * See discussion above.
388 static XLogwrtResult LogwrtResult
= {{0, 0}, {0, 0}};
391 * openLogFile is -1 or a kernel FD for an open log file segment.
392 * When it's open, openLogOff is the current seek offset in the file.
393 * openLogId/openLogSeg identify the segment. These variables are only
394 * used to write the XLOG, and so will normally refer to the active segment.
396 static int openLogFile
= -1;
397 static uint32 openLogId
= 0;
398 static uint32 openLogSeg
= 0;
399 static uint32 openLogOff
= 0;
402 * These variables are used similarly to the ones above, but for reading
403 * the XLOG. Note, however, that readOff generally represents the offset
404 * of the page just read, not the seek position of the FD itself, which
405 * will be just past that page.
407 static int readFile
= -1;
408 static uint32 readId
= 0;
409 static uint32 readSeg
= 0;
410 static uint32 readOff
= 0;
412 /* Buffer for currently read page (XLOG_BLCKSZ bytes) */
413 static char *readBuf
= NULL
;
415 /* Buffer for current ReadRecord result (expandable) */
416 static char *readRecordBuf
= NULL
;
417 static uint32 readRecordBufSize
= 0;
419 /* State information for XLOG reading */
420 static XLogRecPtr ReadRecPtr
; /* start of last record read */
421 static XLogRecPtr EndRecPtr
; /* end+1 of last record read */
422 static XLogRecord
*nextRecord
= NULL
;
423 static TimeLineID lastPageTLI
= 0;
424 static XLogRecPtr minRecoveryPoint
; /* local copy of ControlFile->minRecoveryPoint */
425 static bool updateMinRecoveryPoint
= true;
427 static bool InRedo
= false;
430 * Flag set by interrupt handlers for later service in the redo loop.
432 static volatile sig_atomic_t got_SIGHUP
= false;
433 static volatile sig_atomic_t shutdown_requested
= false;
435 * Flag set when executing a restore command, to tell SIGTERM signal handler
436 * that it's safe to just proc_exit.
438 static volatile sig_atomic_t in_restore_command
= false;
441 static void XLogArchiveNotify(const char *xlog
);
442 static void XLogArchiveNotifySeg(uint32 log
, uint32 seg
);
443 static bool XLogArchiveCheckDone(const char *xlog
);
444 static bool XLogArchiveIsBusy(const char *xlog
);
445 static void XLogArchiveCleanup(const char *xlog
);
446 static void readRecoveryCommandFile(void);
447 static void exitArchiveRecovery(TimeLineID endTLI
,
448 uint32 endLogId
, uint32 endLogSeg
);
449 static bool recoveryStopsHere(XLogRecord
*record
, bool *includeThis
);
450 static void CheckPointGuts(XLogRecPtr checkPointRedo
, int flags
);
452 static bool XLogCheckBuffer(XLogRecData
*rdata
, bool doPageWrites
,
453 XLogRecPtr
*lsn
, BkpBlock
*bkpb
);
454 static bool AdvanceXLInsertBuffer(bool new_segment
);
455 static void XLogWrite(XLogwrtRqst WriteRqst
, bool flexible
, bool xlog_switch
);
456 static int XLogFileInit(uint32 log
, uint32 seg
,
457 bool *use_existent
, bool use_lock
);
458 static bool InstallXLogFileSegment(uint32
*log
, uint32
*seg
, char *tmppath
,
459 bool find_free
, int *max_advance
,
461 static int XLogFileOpen(uint32 log
, uint32 seg
);
462 static int XLogFileRead(uint32 log
, uint32 seg
, int emode
);
463 static void XLogFileClose(void);
464 static bool RestoreArchivedFile(char *path
, const char *xlogfname
,
465 const char *recovername
, off_t expectedSize
);
466 static void PreallocXlogFiles(XLogRecPtr endptr
);
467 static void RemoveOldXlogFiles(uint32 log
, uint32 seg
, XLogRecPtr endptr
);
468 static void ValidateXLOGDirectoryStructure(void);
469 static void CleanupBackupHistory(void);
470 static void UpdateMinRecoveryPoint(XLogRecPtr lsn
, bool force
);
471 static XLogRecord
*ReadRecord(XLogRecPtr
*RecPtr
, int emode
);
472 static bool ValidXLOGHeader(XLogPageHeader hdr
, int emode
);
473 static XLogRecord
*ReadCheckpointRecord(XLogRecPtr RecPtr
, int whichChkpt
);
474 static List
*readTimeLineHistory(TimeLineID targetTLI
);
475 static bool existsTimeLineHistory(TimeLineID probeTLI
);
476 static TimeLineID
findNewestTimeLine(TimeLineID startTLI
);
477 static void writeTimeLineHistory(TimeLineID newTLI
, TimeLineID parentTLI
,
479 uint32 endLogId
, uint32 endLogSeg
);
480 static void WriteControlFile(void);
481 static void ReadControlFile(void);
482 static char *str_time(pg_time_t tnow
);
484 static void xlog_outrec(StringInfo buf
, XLogRecord
*record
);
486 static void issue_xlog_fsync(void);
487 static void pg_start_backup_callback(int code
, Datum arg
);
488 static bool read_backup_label(XLogRecPtr
*checkPointLoc
,
489 XLogRecPtr
*minRecoveryLoc
);
490 static void rm_redo_error_callback(void *arg
);
491 static int get_sync_bit(int method
);
495 * Insert an XLOG record having the specified RMID and info bytes,
496 * with the body of the record being the data chunk(s) described by
497 * the rdata chain (see xlog.h for notes about rdata).
499 * Returns XLOG pointer to end of record (beginning of next record).
500 * This can be used as LSN for data pages affected by the logged action.
501 * (LSN is the XLOG point up to which the XLOG must be flushed to disk
502 * before the data page can be written out. This implements the basic
503 * WAL rule "write the log before the data".)
505 * NB: this routine feels free to scribble on the XLogRecData structs,
506 * though not on the data they reference. This is OK since the XLogRecData
507 * structs are always just temporaries in the calling code.
510 XLogInsert(RmgrId rmid
, uint8 info
, XLogRecData
*rdata
)
512 XLogCtlInsert
*Insert
= &XLogCtl
->Insert
;
514 XLogContRecord
*contrecord
;
516 XLogRecPtr WriteRqst
;
520 Buffer dtbuf
[XLR_MAX_BKP_BLOCKS
];
521 bool dtbuf_bkp
[XLR_MAX_BKP_BLOCKS
];
522 BkpBlock dtbuf_xlg
[XLR_MAX_BKP_BLOCKS
];
523 XLogRecPtr dtbuf_lsn
[XLR_MAX_BKP_BLOCKS
];
524 XLogRecData dtbuf_rdt1
[XLR_MAX_BKP_BLOCKS
];
525 XLogRecData dtbuf_rdt2
[XLR_MAX_BKP_BLOCKS
];
526 XLogRecData dtbuf_rdt3
[XLR_MAX_BKP_BLOCKS
];
533 bool isLogSwitch
= (rmid
== RM_XLOG_ID
&& info
== XLOG_SWITCH
);
535 /* cross-check on whether we should be here or not */
536 if (RecoveryInProgress())
537 elog(FATAL
, "cannot make new WAL entries during recovery");
539 /* info's high bits are reserved for use by me */
540 if (info
& XLR_INFO_MASK
)
541 elog(PANIC
, "invalid xlog info mask %02X", info
);
543 TRACE_POSTGRESQL_XLOG_INSERT(rmid
, info
);
546 * In bootstrap mode, we don't actually log anything but XLOG resources;
547 * return a phony record pointer.
549 if (IsBootstrapProcessingMode() && rmid
!= RM_XLOG_ID
)
552 RecPtr
.xrecoff
= SizeOfXLogLongPHD
; /* start of 1st chkpt record */
557 * Here we scan the rdata chain, determine which buffers must be backed
558 * up, and compute the CRC values for the data. Note that the record
559 * header isn't added into the CRC initially since we don't know the final
560 * length or info bits quite yet. Thus, the CRC will represent the CRC of
561 * the whole record in the order "rdata, then backup blocks, then record
564 * We may have to loop back to here if a race condition is detected below.
565 * We could prevent the race by doing all this work while holding the
566 * insert lock, but it seems better to avoid doing CRC calculations while
567 * holding the lock. This means we have to be careful about modifying the
568 * rdata chain until we know we aren't going to loop back again. The only
569 * change we allow ourselves to make earlier is to set rdt->data = NULL in
570 * chain items we have decided we will have to back up the whole buffer
571 * for. This is OK because we will certainly decide the same thing again
572 * for those items if we do it over; doing it here saves an extra pass
573 * over the chain later.
576 for (i
= 0; i
< XLR_MAX_BKP_BLOCKS
; i
++)
578 dtbuf
[i
] = InvalidBuffer
;
579 dtbuf_bkp
[i
] = false;
583 * Decide if we need to do full-page writes in this XLOG record: true if
584 * full_page_writes is on or we have a PITR request for it. Since we
585 * don't yet have the insert lock, forcePageWrites could change under us,
586 * but we'll recheck it once we have the lock.
588 doPageWrites
= fullPageWrites
|| Insert
->forcePageWrites
;
590 INIT_CRC32(rdata_crc
);
594 if (rdt
->buffer
== InvalidBuffer
)
596 /* Simple data, just include it */
598 COMP_CRC32(rdata_crc
, rdt
->data
, rdt
->len
);
602 /* Find info for buffer */
603 for (i
= 0; i
< XLR_MAX_BKP_BLOCKS
; i
++)
605 if (rdt
->buffer
== dtbuf
[i
])
607 /* Buffer already referenced by earlier chain item */
613 COMP_CRC32(rdata_crc
, rdt
->data
, rdt
->len
);
617 if (dtbuf
[i
] == InvalidBuffer
)
619 /* OK, put it in this slot */
620 dtbuf
[i
] = rdt
->buffer
;
621 if (XLogCheckBuffer(rdt
, doPageWrites
,
622 &(dtbuf_lsn
[i
]), &(dtbuf_xlg
[i
])))
630 COMP_CRC32(rdata_crc
, rdt
->data
, rdt
->len
);
635 if (i
>= XLR_MAX_BKP_BLOCKS
)
636 elog(PANIC
, "can backup at most %d blocks per xlog record",
639 /* Break out of loop when rdt points to last chain item */
640 if (rdt
->next
== NULL
)
646 * Now add the backup block headers and data into the CRC
648 for (i
= 0; i
< XLR_MAX_BKP_BLOCKS
; i
++)
652 BkpBlock
*bkpb
= &(dtbuf_xlg
[i
]);
655 COMP_CRC32(rdata_crc
,
658 page
= (char *) BufferGetBlock(dtbuf
[i
]);
659 if (bkpb
->hole_length
== 0)
661 COMP_CRC32(rdata_crc
,
667 /* must skip the hole */
668 COMP_CRC32(rdata_crc
,
671 COMP_CRC32(rdata_crc
,
672 page
+ (bkpb
->hole_offset
+ bkpb
->hole_length
),
673 BLCKSZ
- (bkpb
->hole_offset
+ bkpb
->hole_length
));
679 * NOTE: We disallow len == 0 because it provides a useful bit of extra
680 * error checking in ReadRecord. This means that all callers of
681 * XLogInsert must supply at least some not-in-a-buffer data. However, we
682 * make an exception for XLOG SWITCH records because we don't want them to
683 * ever cross a segment boundary.
685 if (len
== 0 && !isLogSwitch
)
686 elog(PANIC
, "invalid xlog record length %u", len
);
688 START_CRIT_SECTION();
690 /* Now wait to get insert lock */
691 LWLockAcquire(WALInsertLock
, LW_EXCLUSIVE
);
694 * Check to see if my RedoRecPtr is out of date. If so, may have to go
695 * back and recompute everything. This can only happen just after a
696 * checkpoint, so it's better to be slow in this case and fast otherwise.
698 * If we aren't doing full-page writes then RedoRecPtr doesn't actually
699 * affect the contents of the XLOG record, so we'll update our local copy
700 * but not force a recomputation.
702 if (!XLByteEQ(RedoRecPtr
, Insert
->RedoRecPtr
))
704 Assert(XLByteLT(RedoRecPtr
, Insert
->RedoRecPtr
));
705 RedoRecPtr
= Insert
->RedoRecPtr
;
709 for (i
= 0; i
< XLR_MAX_BKP_BLOCKS
; i
++)
711 if (dtbuf
[i
] == InvalidBuffer
)
713 if (dtbuf_bkp
[i
] == false &&
714 XLByteLE(dtbuf_lsn
[i
], RedoRecPtr
))
717 * Oops, this buffer now needs to be backed up, but we
718 * didn't think so above. Start over.
720 LWLockRelease(WALInsertLock
);
729 * Also check to see if forcePageWrites was just turned on; if we weren't
730 * already doing full-page writes then go back and recompute. (If it was
731 * just turned off, we could recompute the record without full pages, but
732 * we choose not to bother.)
734 if (Insert
->forcePageWrites
&& !doPageWrites
)
736 /* Oops, must redo it with full-page data */
737 LWLockRelease(WALInsertLock
);
743 * Make additional rdata chain entries for the backup blocks, so that we
744 * don't need to special-case them in the write loop. Note that we have
745 * now irrevocably changed the input rdata chain. At the exit of this
746 * loop, write_len includes the backup block data.
748 * Also set the appropriate info bits to show which buffers were backed
749 * up. The i'th XLR_SET_BKP_BLOCK bit corresponds to the i'th distinct
750 * buffer value (ignoring InvalidBuffer) appearing in the rdata chain.
753 for (i
= 0; i
< XLR_MAX_BKP_BLOCKS
; i
++)
761 info
|= XLR_SET_BKP_BLOCK(i
);
763 bkpb
= &(dtbuf_xlg
[i
]);
764 page
= (char *) BufferGetBlock(dtbuf
[i
]);
766 rdt
->next
= &(dtbuf_rdt1
[i
]);
769 rdt
->data
= (char *) bkpb
;
770 rdt
->len
= sizeof(BkpBlock
);
771 write_len
+= sizeof(BkpBlock
);
773 rdt
->next
= &(dtbuf_rdt2
[i
]);
776 if (bkpb
->hole_length
== 0)
785 /* must skip the hole */
787 rdt
->len
= bkpb
->hole_offset
;
788 write_len
+= bkpb
->hole_offset
;
790 rdt
->next
= &(dtbuf_rdt3
[i
]);
793 rdt
->data
= page
+ (bkpb
->hole_offset
+ bkpb
->hole_length
);
794 rdt
->len
= BLCKSZ
- (bkpb
->hole_offset
+ bkpb
->hole_length
);
795 write_len
+= rdt
->len
;
801 * If we backed up any full blocks and online backup is not in progress,
802 * mark the backup blocks as removable. This allows the WAL archiver to
803 * know whether it is safe to compress archived WAL data by transforming
804 * full-block records into the non-full-block format.
806 * Note: we could just set the flag whenever !forcePageWrites, but
807 * defining it like this leaves the info bit free for some potential other
808 * use in records without any backup blocks.
810 if ((info
& XLR_BKP_BLOCK_MASK
) && !Insert
->forcePageWrites
)
811 info
|= XLR_BKP_REMOVABLE
;
814 * If there isn't enough space on the current XLOG page for a record
815 * header, advance to the next page (leaving the unused space as zeroes).
818 freespace
= INSERT_FREESPACE(Insert
);
819 if (freespace
< SizeOfXLogRecord
)
821 updrqst
= AdvanceXLInsertBuffer(false);
822 freespace
= INSERT_FREESPACE(Insert
);
825 /* Compute record's XLOG location */
826 curridx
= Insert
->curridx
;
827 INSERT_RECPTR(RecPtr
, Insert
, curridx
);
830 * If the record is an XLOG_SWITCH, and we are exactly at the start of a
831 * segment, we need not insert it (and don't want to because we'd like
832 * consecutive switch requests to be no-ops). Instead, make sure
833 * everything is written and flushed through the end of the prior segment,
834 * and return the prior segment's end address.
837 (RecPtr
.xrecoff
% XLogSegSize
) == SizeOfXLogLongPHD
)
839 /* We can release insert lock immediately */
840 LWLockRelease(WALInsertLock
);
842 RecPtr
.xrecoff
-= SizeOfXLogLongPHD
;
843 if (RecPtr
.xrecoff
== 0)
845 /* crossing a logid boundary */
847 RecPtr
.xrecoff
= XLogFileSize
;
850 LWLockAcquire(WALWriteLock
, LW_EXCLUSIVE
);
851 LogwrtResult
= XLogCtl
->Write
.LogwrtResult
;
852 if (!XLByteLE(RecPtr
, LogwrtResult
.Flush
))
854 XLogwrtRqst FlushRqst
;
856 FlushRqst
.Write
= RecPtr
;
857 FlushRqst
.Flush
= RecPtr
;
858 XLogWrite(FlushRqst
, false, false);
860 LWLockRelease(WALWriteLock
);
867 /* Insert record header */
869 record
= (XLogRecord
*) Insert
->currpos
;
870 record
->xl_prev
= Insert
->PrevRecord
;
871 record
->xl_xid
= GetCurrentTransactionIdIfAny();
872 record
->xl_tot_len
= SizeOfXLogRecord
+ write_len
;
873 record
->xl_len
= len
; /* doesn't include backup blocks */
874 record
->xl_info
= info
;
875 record
->xl_rmid
= rmid
;
877 /* Now we can finish computing the record's CRC */
878 COMP_CRC32(rdata_crc
, (char *) record
+ sizeof(pg_crc32
),
879 SizeOfXLogRecord
- sizeof(pg_crc32
));
880 FIN_CRC32(rdata_crc
);
881 record
->xl_crc
= rdata_crc
;
888 initStringInfo(&buf
);
889 appendStringInfo(&buf
, "INSERT @ %X/%X: ",
890 RecPtr
.xlogid
, RecPtr
.xrecoff
);
891 xlog_outrec(&buf
, record
);
892 if (rdata
->data
!= NULL
)
894 appendStringInfo(&buf
, " - ");
895 RmgrTable
[record
->xl_rmid
].rm_desc(&buf
, record
->xl_info
, rdata
->data
);
897 elog(LOG
, "%s", buf
.data
);
902 /* Record begin of record in appropriate places */
903 ProcLastRecPtr
= RecPtr
;
904 Insert
->PrevRecord
= RecPtr
;
906 Insert
->currpos
+= SizeOfXLogRecord
;
907 freespace
-= SizeOfXLogRecord
;
910 * Append the data, including backup blocks if any
914 while (rdata
->data
== NULL
)
919 if (rdata
->len
> freespace
)
921 memcpy(Insert
->currpos
, rdata
->data
, freespace
);
922 rdata
->data
+= freespace
;
923 rdata
->len
-= freespace
;
924 write_len
-= freespace
;
928 memcpy(Insert
->currpos
, rdata
->data
, rdata
->len
);
929 freespace
-= rdata
->len
;
930 write_len
-= rdata
->len
;
931 Insert
->currpos
+= rdata
->len
;
937 /* Use next buffer */
938 updrqst
= AdvanceXLInsertBuffer(false);
939 curridx
= Insert
->curridx
;
940 /* Insert cont-record header */
941 Insert
->currpage
->xlp_info
|= XLP_FIRST_IS_CONTRECORD
;
942 contrecord
= (XLogContRecord
*) Insert
->currpos
;
943 contrecord
->xl_rem_len
= write_len
;
944 Insert
->currpos
+= SizeOfXLogContRecord
;
945 freespace
= INSERT_FREESPACE(Insert
);
948 /* Ensure next record will be properly aligned */
949 Insert
->currpos
= (char *) Insert
->currpage
+
950 MAXALIGN(Insert
->currpos
- (char *) Insert
->currpage
);
951 freespace
= INSERT_FREESPACE(Insert
);
954 * The recptr I return is the beginning of the *next* record. This will be
955 * stored as LSN for changed data pages...
957 INSERT_RECPTR(RecPtr
, Insert
, curridx
);
960 * If the record is an XLOG_SWITCH, we must now write and flush all the
961 * existing data, and then forcibly advance to the start of the next
962 * segment. It's not good to do this I/O while holding the insert lock,
963 * but there seems too much risk of confusion if we try to release the
964 * lock sooner. Fortunately xlog switch needn't be a high-performance
965 * operation anyway...
969 XLogCtlWrite
*Write
= &XLogCtl
->Write
;
970 XLogwrtRqst FlushRqst
;
971 XLogRecPtr OldSegEnd
;
973 TRACE_POSTGRESQL_XLOG_SWITCH();
975 LWLockAcquire(WALWriteLock
, LW_EXCLUSIVE
);
978 * Flush through the end of the page containing XLOG_SWITCH, and
979 * perform end-of-segment actions (eg, notifying archiver).
981 WriteRqst
= XLogCtl
->xlblocks
[curridx
];
982 FlushRqst
.Write
= WriteRqst
;
983 FlushRqst
.Flush
= WriteRqst
;
984 XLogWrite(FlushRqst
, false, true);
986 /* Set up the next buffer as first page of next segment */
987 /* Note: AdvanceXLInsertBuffer cannot need to do I/O here */
988 (void) AdvanceXLInsertBuffer(true);
990 /* There should be no unwritten data */
991 curridx
= Insert
->curridx
;
992 Assert(curridx
== Write
->curridx
);
994 /* Compute end address of old segment */
995 OldSegEnd
= XLogCtl
->xlblocks
[curridx
];
996 OldSegEnd
.xrecoff
-= XLOG_BLCKSZ
;
997 if (OldSegEnd
.xrecoff
== 0)
999 /* crossing a logid boundary */
1000 OldSegEnd
.xlogid
-= 1;
1001 OldSegEnd
.xrecoff
= XLogFileSize
;
1004 /* Make it look like we've written and synced all of old segment */
1005 LogwrtResult
.Write
= OldSegEnd
;
1006 LogwrtResult
.Flush
= OldSegEnd
;
1009 * Update shared-memory status --- this code should match XLogWrite
1012 /* use volatile pointer to prevent code rearrangement */
1013 volatile XLogCtlData
*xlogctl
= XLogCtl
;
1015 SpinLockAcquire(&xlogctl
->info_lck
);
1016 xlogctl
->LogwrtResult
= LogwrtResult
;
1017 if (XLByteLT(xlogctl
->LogwrtRqst
.Write
, LogwrtResult
.Write
))
1018 xlogctl
->LogwrtRqst
.Write
= LogwrtResult
.Write
;
1019 if (XLByteLT(xlogctl
->LogwrtRqst
.Flush
, LogwrtResult
.Flush
))
1020 xlogctl
->LogwrtRqst
.Flush
= LogwrtResult
.Flush
;
1021 SpinLockRelease(&xlogctl
->info_lck
);
1024 Write
->LogwrtResult
= LogwrtResult
;
1026 LWLockRelease(WALWriteLock
);
1028 updrqst
= false; /* done already */
1032 /* normal case, ie not xlog switch */
1034 /* Need to update shared LogwrtRqst if some block was filled up */
1035 if (freespace
< SizeOfXLogRecord
)
1037 /* curridx is filled and available for writing out */
1042 /* if updrqst already set, write through end of previous buf */
1043 curridx
= PrevBufIdx(curridx
);
1045 WriteRqst
= XLogCtl
->xlblocks
[curridx
];
1048 LWLockRelease(WALInsertLock
);
1052 /* use volatile pointer to prevent code rearrangement */
1053 volatile XLogCtlData
*xlogctl
= XLogCtl
;
1055 SpinLockAcquire(&xlogctl
->info_lck
);
1056 /* advance global request to include new block(s) */
1057 if (XLByteLT(xlogctl
->LogwrtRqst
.Write
, WriteRqst
))
1058 xlogctl
->LogwrtRqst
.Write
= WriteRqst
;
1059 /* update local result copy while I have the chance */
1060 LogwrtResult
= xlogctl
->LogwrtResult
;
1061 SpinLockRelease(&xlogctl
->info_lck
);
1064 XactLastRecEnd
= RecPtr
;
1072 * Determine whether the buffer referenced by an XLogRecData item has to
1073 * be backed up, and if so fill a BkpBlock struct for it. In any case
1074 * save the buffer's LSN at *lsn.
1077 XLogCheckBuffer(XLogRecData
*rdata
, bool doPageWrites
,
1078 XLogRecPtr
*lsn
, BkpBlock
*bkpb
)
1082 page
= BufferGetPage(rdata
->buffer
);
1085 * XXX We assume page LSN is first data on *every* page that can be passed
1086 * to XLogInsert, whether it otherwise has the standard page layout or
1089 *lsn
= PageGetLSN(page
);
1092 XLByteLE(PageGetLSN(page
), RedoRecPtr
))
1095 * The page needs to be backed up, so set up *bkpb
1097 BufferGetTag(rdata
->buffer
, &bkpb
->node
, &bkpb
->fork
, &bkpb
->block
);
1099 if (rdata
->buffer_std
)
1101 /* Assume we can omit data between pd_lower and pd_upper */
1102 uint16 lower
= ((PageHeader
) page
)->pd_lower
;
1103 uint16 upper
= ((PageHeader
) page
)->pd_upper
;
1105 if (lower
>= SizeOfPageHeaderData
&&
1109 bkpb
->hole_offset
= lower
;
1110 bkpb
->hole_length
= upper
- lower
;
1114 /* No "hole" to compress out */
1115 bkpb
->hole_offset
= 0;
1116 bkpb
->hole_length
= 0;
1121 /* Not a standard page header, don't try to eliminate "hole" */
1122 bkpb
->hole_offset
= 0;
1123 bkpb
->hole_length
= 0;
1126 return true; /* buffer requires backup */
1129 return false; /* buffer does not need to be backed up */
1135 * Create an archive notification file
1137 * The name of the notification file is the message that will be picked up
1138 * by the archiver, e.g. we write 0000000100000001000000C6.ready
1139 * and the archiver then knows to archive XLOGDIR/0000000100000001000000C6,
1140 * then when complete, rename it to 0000000100000001000000C6.done
1143 XLogArchiveNotify(const char *xlog
)
1145 char archiveStatusPath
[MAXPGPATH
];
1148 /* insert an otherwise empty file called <XLOG>.ready */
1149 StatusFilePath(archiveStatusPath
, xlog
, ".ready");
1150 fd
= AllocateFile(archiveStatusPath
, "w");
1154 (errcode_for_file_access(),
1155 errmsg("could not create archive status file \"%s\": %m",
1156 archiveStatusPath
)));
1162 (errcode_for_file_access(),
1163 errmsg("could not write archive status file \"%s\": %m",
1164 archiveStatusPath
)));
1168 /* Notify archiver that it's got something to do */
1169 if (IsUnderPostmaster
)
1170 SendPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER
);
1174 * Convenience routine to notify using log/seg representation of filename
1177 XLogArchiveNotifySeg(uint32 log
, uint32 seg
)
1179 char xlog
[MAXFNAMELEN
];
1181 XLogFileName(xlog
, ThisTimeLineID
, log
, seg
);
1182 XLogArchiveNotify(xlog
);
1186 * XLogArchiveCheckDone
1188 * This is called when we are ready to delete or recycle an old XLOG segment
1189 * file or backup history file. If it is okay to delete it then return true.
1190 * If it is not time to delete it, make sure a .ready file exists, and return
1193 * If <XLOG>.done exists, then return true; else if <XLOG>.ready exists,
1194 * then return false; else create <XLOG>.ready and return false.
1196 * The reason we do things this way is so that if the original attempt to
1197 * create <XLOG>.ready fails, we'll retry during subsequent checkpoints.
1200 XLogArchiveCheckDone(const char *xlog
)
1202 char archiveStatusPath
[MAXPGPATH
];
1203 struct stat stat_buf
;
1205 /* Always deletable if archiving is off */
1206 if (!XLogArchivingActive())
1209 /* First check for .done --- this means archiver is done with it */
1210 StatusFilePath(archiveStatusPath
, xlog
, ".done");
1211 if (stat(archiveStatusPath
, &stat_buf
) == 0)
1214 /* check for .ready --- this means archiver is still busy with it */
1215 StatusFilePath(archiveStatusPath
, xlog
, ".ready");
1216 if (stat(archiveStatusPath
, &stat_buf
) == 0)
1219 /* Race condition --- maybe archiver just finished, so recheck */
1220 StatusFilePath(archiveStatusPath
, xlog
, ".done");
1221 if (stat(archiveStatusPath
, &stat_buf
) == 0)
1224 /* Retry creation of the .ready file */
1225 XLogArchiveNotify(xlog
);
1232 * Check to see if an XLOG segment file is still unarchived.
1233 * This is almost but not quite the inverse of XLogArchiveCheckDone: in
1234 * the first place we aren't chartered to recreate the .ready file, and
1235 * in the second place we should consider that if the file is already gone
1236 * then it's not busy. (This check is needed to handle the race condition
1237 * that a checkpoint already deleted the no-longer-needed file.)
1240 XLogArchiveIsBusy(const char *xlog
)
1242 char archiveStatusPath
[MAXPGPATH
];
1243 struct stat stat_buf
;
1245 /* First check for .done --- this means archiver is done with it */
1246 StatusFilePath(archiveStatusPath
, xlog
, ".done");
1247 if (stat(archiveStatusPath
, &stat_buf
) == 0)
1250 /* check for .ready --- this means archiver is still busy with it */
1251 StatusFilePath(archiveStatusPath
, xlog
, ".ready");
1252 if (stat(archiveStatusPath
, &stat_buf
) == 0)
1255 /* Race condition --- maybe archiver just finished, so recheck */
1256 StatusFilePath(archiveStatusPath
, xlog
, ".done");
1257 if (stat(archiveStatusPath
, &stat_buf
) == 0)
1261 * Check to see if the WAL file has been removed by checkpoint,
1262 * which implies it has already been archived, and explains why we
1263 * can't see a status file for it.
1265 snprintf(archiveStatusPath
, MAXPGPATH
, XLOGDIR
"/%s", xlog
);
1266 if (stat(archiveStatusPath
, &stat_buf
) != 0 &&
1274 * XLogArchiveCleanup
1276 * Cleanup archive notification file(s) for a particular xlog segment
1279 XLogArchiveCleanup(const char *xlog
)
1281 char archiveStatusPath
[MAXPGPATH
];
1283 /* Remove the .done file */
1284 StatusFilePath(archiveStatusPath
, xlog
, ".done");
1285 unlink(archiveStatusPath
);
1286 /* should we complain about failure? */
1288 /* Remove the .ready file if present --- normally it shouldn't be */
1289 StatusFilePath(archiveStatusPath
, xlog
, ".ready");
1290 unlink(archiveStatusPath
);
1291 /* should we complain about failure? */
1295 * Advance the Insert state to the next buffer page, writing out the next
1296 * buffer if it still contains unwritten data.
1298 * If new_segment is TRUE then we set up the next buffer page as the first
1299 * page of the next xlog segment file, possibly but not usually the next
1300 * consecutive file page.
1302 * The global LogwrtRqst.Write pointer needs to be advanced to include the
1303 * just-filled page. If we can do this for free (without an extra lock),
1304 * we do so here. Otherwise the caller must do it. We return TRUE if the
1305 * request update still needs to be done, FALSE if we did it internally.
1307 * Must be called with WALInsertLock held.
1310 AdvanceXLInsertBuffer(bool new_segment
)
1312 XLogCtlInsert
*Insert
= &XLogCtl
->Insert
;
1313 XLogCtlWrite
*Write
= &XLogCtl
->Write
;
1314 int nextidx
= NextBufIdx(Insert
->curridx
);
1315 bool update_needed
= true;
1316 XLogRecPtr OldPageRqstPtr
;
1317 XLogwrtRqst WriteRqst
;
1318 XLogRecPtr NewPageEndPtr
;
1319 XLogPageHeader NewPage
;
1321 /* Use Insert->LogwrtResult copy if it's more fresh */
1322 if (XLByteLT(LogwrtResult
.Write
, Insert
->LogwrtResult
.Write
))
1323 LogwrtResult
= Insert
->LogwrtResult
;
1326 * Get ending-offset of the buffer page we need to replace (this may be
1327 * zero if the buffer hasn't been used yet). Fall through if it's already
1330 OldPageRqstPtr
= XLogCtl
->xlblocks
[nextidx
];
1331 if (!XLByteLE(OldPageRqstPtr
, LogwrtResult
.Write
))
1333 /* nope, got work to do... */
1334 XLogRecPtr FinishedPageRqstPtr
;
1336 FinishedPageRqstPtr
= XLogCtl
->xlblocks
[Insert
->curridx
];
1338 /* Before waiting, get info_lck and update LogwrtResult */
1340 /* use volatile pointer to prevent code rearrangement */
1341 volatile XLogCtlData
*xlogctl
= XLogCtl
;
1343 SpinLockAcquire(&xlogctl
->info_lck
);
1344 if (XLByteLT(xlogctl
->LogwrtRqst
.Write
, FinishedPageRqstPtr
))
1345 xlogctl
->LogwrtRqst
.Write
= FinishedPageRqstPtr
;
1346 LogwrtResult
= xlogctl
->LogwrtResult
;
1347 SpinLockRelease(&xlogctl
->info_lck
);
1350 update_needed
= false; /* Did the shared-request update */
1352 if (XLByteLE(OldPageRqstPtr
, LogwrtResult
.Write
))
1354 /* OK, someone wrote it already */
1355 Insert
->LogwrtResult
= LogwrtResult
;
1359 /* Must acquire write lock */
1360 LWLockAcquire(WALWriteLock
, LW_EXCLUSIVE
);
1361 LogwrtResult
= Write
->LogwrtResult
;
1362 if (XLByteLE(OldPageRqstPtr
, LogwrtResult
.Write
))
1364 /* OK, someone wrote it already */
1365 LWLockRelease(WALWriteLock
);
1366 Insert
->LogwrtResult
= LogwrtResult
;
1371 * Have to write buffers while holding insert lock. This is
1372 * not good, so only write as much as we absolutely must.
1374 TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_START();
1375 WriteRqst
.Write
= OldPageRqstPtr
;
1376 WriteRqst
.Flush
.xlogid
= 0;
1377 WriteRqst
.Flush
.xrecoff
= 0;
1378 XLogWrite(WriteRqst
, false, false);
1379 LWLockRelease(WALWriteLock
);
1380 Insert
->LogwrtResult
= LogwrtResult
;
1381 TRACE_POSTGRESQL_WAL_BUFFER_WRITE_DIRTY_DONE();
1387 * Now the next buffer slot is free and we can set it up to be the next
1390 NewPageEndPtr
= XLogCtl
->xlblocks
[Insert
->curridx
];
1394 /* force it to a segment start point */
1395 NewPageEndPtr
.xrecoff
+= XLogSegSize
- 1;
1396 NewPageEndPtr
.xrecoff
-= NewPageEndPtr
.xrecoff
% XLogSegSize
;
1399 if (NewPageEndPtr
.xrecoff
>= XLogFileSize
)
1401 /* crossing a logid boundary */
1402 NewPageEndPtr
.xlogid
+= 1;
1403 NewPageEndPtr
.xrecoff
= XLOG_BLCKSZ
;
1406 NewPageEndPtr
.xrecoff
+= XLOG_BLCKSZ
;
1407 XLogCtl
->xlblocks
[nextidx
] = NewPageEndPtr
;
1408 NewPage
= (XLogPageHeader
) (XLogCtl
->pages
+ nextidx
* (Size
) XLOG_BLCKSZ
);
1410 Insert
->curridx
= nextidx
;
1411 Insert
->currpage
= NewPage
;
1413 Insert
->currpos
= ((char *) NewPage
) +SizeOfXLogShortPHD
;
1416 * Be sure to re-zero the buffer so that bytes beyond what we've written
1417 * will look like zeroes and not valid XLOG records...
1419 MemSet((char *) NewPage
, 0, XLOG_BLCKSZ
);
1422 * Fill the new page's header
1424 NewPage
->xlp_magic
= XLOG_PAGE_MAGIC
;
1426 /* NewPage->xlp_info = 0; */ /* done by memset */
1427 NewPage
->xlp_tli
= ThisTimeLineID
;
1428 NewPage
->xlp_pageaddr
.xlogid
= NewPageEndPtr
.xlogid
;
1429 NewPage
->xlp_pageaddr
.xrecoff
= NewPageEndPtr
.xrecoff
- XLOG_BLCKSZ
;
1432 * If first page of an XLOG segment file, make it a long header.
1434 if ((NewPage
->xlp_pageaddr
.xrecoff
% XLogSegSize
) == 0)
1436 XLogLongPageHeader NewLongPage
= (XLogLongPageHeader
) NewPage
;
1438 NewLongPage
->xlp_sysid
= ControlFile
->system_identifier
;
1439 NewLongPage
->xlp_seg_size
= XLogSegSize
;
1440 NewLongPage
->xlp_xlog_blcksz
= XLOG_BLCKSZ
;
1441 NewPage
->xlp_info
|= XLP_LONG_HEADER
;
1443 Insert
->currpos
= ((char *) NewPage
) +SizeOfXLogLongPHD
;
1446 return update_needed
;
1450 * Check whether we've consumed enough xlog space that a checkpoint is needed.
1452 * Caller must have just finished filling the open log file (so that
1453 * openLogId/openLogSeg are valid). We measure the distance from RedoRecPtr
1454 * to the open log file and see if that exceeds CheckPointSegments.
1456 * Note: it is caller's responsibility that RedoRecPtr is up-to-date.
1459 XLogCheckpointNeeded(void)
1462 * A straight computation of segment number could overflow 32 bits. Rather
1463 * than assuming we have working 64-bit arithmetic, we compare the
1464 * highest-order bits separately, and force a checkpoint immediately when
1469 uint32 old_highbits
,
1472 old_segno
= (RedoRecPtr
.xlogid
% XLogSegSize
) * XLogSegsPerFile
+
1473 (RedoRecPtr
.xrecoff
/ XLogSegSize
);
1474 old_highbits
= RedoRecPtr
.xlogid
/ XLogSegSize
;
1475 new_segno
= (openLogId
% XLogSegSize
) * XLogSegsPerFile
+ openLogSeg
;
1476 new_highbits
= openLogId
/ XLogSegSize
;
1477 if (new_highbits
!= old_highbits
||
1478 new_segno
>= old_segno
+ (uint32
) (CheckPointSegments
- 1))
1484 * Write and/or fsync the log at least as far as WriteRqst indicates.
1486 * If flexible == TRUE, we don't have to write as far as WriteRqst, but
1487 * may stop at any convenient boundary (such as a cache or logfile boundary).
1488 * This option allows us to avoid uselessly issuing multiple writes when a
1489 * single one would do.
1491 * If xlog_switch == TRUE, we are intending an xlog segment switch, so
1492 * perform end-of-segment actions after writing the last page, even if
1493 * it's not physically the end of its segment. (NB: this will work properly
1494 * only if caller specifies WriteRqst == page-end and flexible == false,
1495 * and there is some data to write.)
1497 * Must be called with WALWriteLock held.
1500 XLogWrite(XLogwrtRqst WriteRqst
, bool flexible
, bool xlog_switch
)
1502 XLogCtlWrite
*Write
= &XLogCtl
->Write
;
1504 bool last_iteration
;
1512 /* We should always be inside a critical section here */
1513 Assert(CritSectionCount
> 0);
1516 * Update local LogwrtResult (caller probably did this already, but...)
1518 LogwrtResult
= Write
->LogwrtResult
;
1521 * Since successive pages in the xlog cache are consecutively allocated,
1522 * we can usually gather multiple pages together and issue just one
1523 * write() call. npages is the number of pages we have determined can be
1524 * written together; startidx is the cache block index of the first one,
1525 * and startoffset is the file offset at which it should go. The latter
1526 * two variables are only valid when npages > 0, but we must initialize
1527 * all of them to keep the compiler quiet.
1534 * Within the loop, curridx is the cache block index of the page to
1535 * consider writing. We advance Write->curridx only after successfully
1536 * writing pages. (Right now, this refinement is useless since we are
1537 * going to PANIC if any error occurs anyway; but someday it may come in
1540 curridx
= Write
->curridx
;
1542 while (XLByteLT(LogwrtResult
.Write
, WriteRqst
.Write
))
1545 * Make sure we're not ahead of the insert process. This could happen
1546 * if we're passed a bogus WriteRqst.Write that is past the end of the
1547 * last page that's been initialized by AdvanceXLInsertBuffer.
1549 if (!XLByteLT(LogwrtResult
.Write
, XLogCtl
->xlblocks
[curridx
]))
1550 elog(PANIC
, "xlog write request %X/%X is past end of log %X/%X",
1551 LogwrtResult
.Write
.xlogid
, LogwrtResult
.Write
.xrecoff
,
1552 XLogCtl
->xlblocks
[curridx
].xlogid
,
1553 XLogCtl
->xlblocks
[curridx
].xrecoff
);
1555 /* Advance LogwrtResult.Write to end of current buffer page */
1556 LogwrtResult
.Write
= XLogCtl
->xlblocks
[curridx
];
1557 ispartialpage
= XLByteLT(WriteRqst
.Write
, LogwrtResult
.Write
);
1559 if (!XLByteInPrevSeg(LogwrtResult
.Write
, openLogId
, openLogSeg
))
1562 * Switch to new logfile segment. We cannot have any pending
1563 * pages here (since we dump what we have at segment end).
1565 Assert(npages
== 0);
1566 if (openLogFile
>= 0)
1568 XLByteToPrevSeg(LogwrtResult
.Write
, openLogId
, openLogSeg
);
1570 /* create/use new log file */
1571 use_existent
= true;
1572 openLogFile
= XLogFileInit(openLogId
, openLogSeg
,
1573 &use_existent
, true);
1577 /* Make sure we have the current logfile open */
1578 if (openLogFile
< 0)
1580 XLByteToPrevSeg(LogwrtResult
.Write
, openLogId
, openLogSeg
);
1581 openLogFile
= XLogFileOpen(openLogId
, openLogSeg
);
1585 /* Add current page to the set of pending pages-to-dump */
1588 /* first of group */
1590 startoffset
= (LogwrtResult
.Write
.xrecoff
- XLOG_BLCKSZ
) % XLogSegSize
;
1595 * Dump the set if this will be the last loop iteration, or if we are
1596 * at the last page of the cache area (since the next page won't be
1597 * contiguous in memory), or if we are at the end of the logfile
1600 last_iteration
= !XLByteLT(LogwrtResult
.Write
, WriteRqst
.Write
);
1602 finishing_seg
= !ispartialpage
&&
1603 (startoffset
+ npages
* XLOG_BLCKSZ
) >= XLogSegSize
;
1605 if (last_iteration
||
1606 curridx
== XLogCtl
->XLogCacheBlck
||
1612 /* Need to seek in the file? */
1613 if (openLogOff
!= startoffset
)
1615 if (lseek(openLogFile
, (off_t
) startoffset
, SEEK_SET
) < 0)
1617 (errcode_for_file_access(),
1618 errmsg("could not seek in log file %u, "
1619 "segment %u to offset %u: %m",
1620 openLogId
, openLogSeg
, startoffset
)));
1621 openLogOff
= startoffset
;
1624 /* OK to write the page(s) */
1625 from
= XLogCtl
->pages
+ startidx
* (Size
) XLOG_BLCKSZ
;
1626 nbytes
= npages
* (Size
) XLOG_BLCKSZ
;
1628 if (write(openLogFile
, from
, nbytes
) != nbytes
)
1630 /* if write didn't set errno, assume no disk space */
1634 (errcode_for_file_access(),
1635 errmsg("could not write to log file %u, segment %u "
1636 "at offset %u, length %lu: %m",
1637 openLogId
, openLogSeg
,
1638 openLogOff
, (unsigned long) nbytes
)));
1641 /* Update state for write */
1642 openLogOff
+= nbytes
;
1643 Write
->curridx
= ispartialpage
? curridx
: NextBufIdx(curridx
);
1647 * If we just wrote the whole last page of a logfile segment,
1648 * fsync the segment immediately. This avoids having to go back
1649 * and re-open prior segments when an fsync request comes along
1650 * later. Doing it here ensures that one and only one backend will
1651 * perform this fsync.
1653 * We also do this if this is the last page written for an xlog
1656 * This is also the right place to notify the Archiver that the
1657 * segment is ready to copy to archival storage, and to update the
1658 * timer for archive_timeout, and to signal for a checkpoint if
1659 * too many logfile segments have been used since the last
1662 if (finishing_seg
|| (xlog_switch
&& last_iteration
))
1665 LogwrtResult
.Flush
= LogwrtResult
.Write
; /* end of page */
1667 if (XLogArchivingActive())
1668 XLogArchiveNotifySeg(openLogId
, openLogSeg
);
1670 Write
->lastSegSwitchTime
= (pg_time_t
) time(NULL
);
1673 * Signal bgwriter to start a checkpoint if we've consumed too
1674 * much xlog since the last one. For speed, we first check
1675 * using the local copy of RedoRecPtr, which might be out of
1676 * date; if it looks like a checkpoint is needed, forcibly
1677 * update RedoRecPtr and recheck.
1679 if (IsUnderPostmaster
&&
1680 XLogCheckpointNeeded())
1682 (void) GetRedoRecPtr();
1683 if (XLogCheckpointNeeded())
1684 RequestCheckpoint(CHECKPOINT_CAUSE_XLOG
);
1691 /* Only asked to write a partial page */
1692 LogwrtResult
.Write
= WriteRqst
.Write
;
1695 curridx
= NextBufIdx(curridx
);
1697 /* If flexible, break out of loop as soon as we wrote something */
1698 if (flexible
&& npages
== 0)
1702 Assert(npages
== 0);
1703 Assert(curridx
== Write
->curridx
);
1706 * If asked to flush, do so
1708 if (XLByteLT(LogwrtResult
.Flush
, WriteRqst
.Flush
) &&
1709 XLByteLT(LogwrtResult
.Flush
, LogwrtResult
.Write
))
1712 * Could get here without iterating above loop, in which case we might
1713 * have no open file or the wrong one. However, we do not need to
1714 * fsync more than one file.
1716 if (sync_method
!= SYNC_METHOD_OPEN
&&
1717 sync_method
!= SYNC_METHOD_OPEN_DSYNC
)
1719 if (openLogFile
>= 0 &&
1720 !XLByteInPrevSeg(LogwrtResult
.Write
, openLogId
, openLogSeg
))
1722 if (openLogFile
< 0)
1724 XLByteToPrevSeg(LogwrtResult
.Write
, openLogId
, openLogSeg
);
1725 openLogFile
= XLogFileOpen(openLogId
, openLogSeg
);
1730 LogwrtResult
.Flush
= LogwrtResult
.Write
;
1734 * Update shared-memory status
1736 * We make sure that the shared 'request' values do not fall behind the
1737 * 'result' values. This is not absolutely essential, but it saves some
1738 * code in a couple of places.
1741 /* use volatile pointer to prevent code rearrangement */
1742 volatile XLogCtlData
*xlogctl
= XLogCtl
;
1744 SpinLockAcquire(&xlogctl
->info_lck
);
1745 xlogctl
->LogwrtResult
= LogwrtResult
;
1746 if (XLByteLT(xlogctl
->LogwrtRqst
.Write
, LogwrtResult
.Write
))
1747 xlogctl
->LogwrtRqst
.Write
= LogwrtResult
.Write
;
1748 if (XLByteLT(xlogctl
->LogwrtRqst
.Flush
, LogwrtResult
.Flush
))
1749 xlogctl
->LogwrtRqst
.Flush
= LogwrtResult
.Flush
;
1750 SpinLockRelease(&xlogctl
->info_lck
);
1753 Write
->LogwrtResult
= LogwrtResult
;
1757 * Record the LSN for an asynchronous transaction commit.
1758 * (This should not be called for aborts, nor for synchronous commits.)
1761 XLogSetAsyncCommitLSN(XLogRecPtr asyncCommitLSN
)
1763 /* use volatile pointer to prevent code rearrangement */
1764 volatile XLogCtlData
*xlogctl
= XLogCtl
;
1766 SpinLockAcquire(&xlogctl
->info_lck
);
1767 if (XLByteLT(xlogctl
->asyncCommitLSN
, asyncCommitLSN
))
1768 xlogctl
->asyncCommitLSN
= asyncCommitLSN
;
1769 SpinLockRelease(&xlogctl
->info_lck
);
1773 * Advance minRecoveryPoint in control file.
1775 * If we crash during recovery, we must reach this point again before the
1776 * database is consistent.
1778 * If 'force' is true, 'lsn' argument is ignored. Otherwise, minRecoveryPoint
1779 * is is only updated if it's not already greater than or equal to 'lsn'.
1782 UpdateMinRecoveryPoint(XLogRecPtr lsn
, bool force
)
1784 /* Quick check using our local copy of the variable */
1785 if (!updateMinRecoveryPoint
|| (!force
&& XLByteLE(lsn
, minRecoveryPoint
)))
1788 LWLockAcquire(ControlFileLock
, LW_EXCLUSIVE
);
1790 /* update local copy */
1791 minRecoveryPoint
= ControlFile
->minRecoveryPoint
;
1794 * An invalid minRecoveryPoint means that we need to recover all the WAL,
1795 * ie. crash recovery. Don't update the control file in that case.
1797 if (minRecoveryPoint
.xlogid
== 0 && minRecoveryPoint
.xrecoff
== 0)
1798 updateMinRecoveryPoint
= false;
1799 else if (force
|| XLByteLT(minRecoveryPoint
, lsn
))
1801 /* use volatile pointer to prevent code rearrangement */
1802 volatile XLogCtlData
*xlogctl
= XLogCtl
;
1803 XLogRecPtr newMinRecoveryPoint
;
1806 * To avoid having to update the control file too often, we update it
1807 * all the way to the last record being replayed, even though 'lsn'
1808 * would suffice for correctness.
1810 SpinLockAcquire(&xlogctl
->info_lck
);
1811 newMinRecoveryPoint
= xlogctl
->replayEndRecPtr
;
1812 SpinLockRelease(&xlogctl
->info_lck
);
1814 /* update control file */
1815 if (XLByteLT(ControlFile
->minRecoveryPoint
, newMinRecoveryPoint
))
1817 ControlFile
->minRecoveryPoint
= newMinRecoveryPoint
;
1818 UpdateControlFile();
1819 minRecoveryPoint
= newMinRecoveryPoint
;
1822 (errmsg("updated min recovery point to %X/%X",
1823 minRecoveryPoint
.xlogid
, minRecoveryPoint
.xrecoff
)));
1826 LWLockRelease(ControlFileLock
);
1830 * Ensure that all XLOG data through the given position is flushed to disk.
1832 * NOTE: this differs from XLogWrite mainly in that the WALWriteLock is not
1833 * already held, and we try to avoid acquiring it if possible.
1836 XLogFlush(XLogRecPtr record
)
1838 XLogRecPtr WriteRqstPtr
;
1839 XLogwrtRqst WriteRqst
;
1842 * During REDO, we don't try to flush the WAL, but update minRecoveryPoint
1845 if (RecoveryInProgress())
1847 UpdateMinRecoveryPoint(record
, false);
1851 /* Quick exit if already known flushed */
1852 if (XLByteLE(record
, LogwrtResult
.Flush
))
1857 elog(LOG
, "xlog flush request %X/%X; write %X/%X; flush %X/%X",
1858 record
.xlogid
, record
.xrecoff
,
1859 LogwrtResult
.Write
.xlogid
, LogwrtResult
.Write
.xrecoff
,
1860 LogwrtResult
.Flush
.xlogid
, LogwrtResult
.Flush
.xrecoff
);
1863 START_CRIT_SECTION();
1866 * Since fsync is usually a horribly expensive operation, we try to
1867 * piggyback as much data as we can on each fsync: if we see any more data
1868 * entered into the xlog buffer, we'll write and fsync that too, so that
1869 * the final value of LogwrtResult.Flush is as large as possible. This
1870 * gives us some chance of avoiding another fsync immediately after.
1873 /* initialize to given target; may increase below */
1874 WriteRqstPtr
= record
;
1876 /* read LogwrtResult and update local state */
1878 /* use volatile pointer to prevent code rearrangement */
1879 volatile XLogCtlData
*xlogctl
= XLogCtl
;
1881 SpinLockAcquire(&xlogctl
->info_lck
);
1882 if (XLByteLT(WriteRqstPtr
, xlogctl
->LogwrtRqst
.Write
))
1883 WriteRqstPtr
= xlogctl
->LogwrtRqst
.Write
;
1884 LogwrtResult
= xlogctl
->LogwrtResult
;
1885 SpinLockRelease(&xlogctl
->info_lck
);
1889 if (!XLByteLE(record
, LogwrtResult
.Flush
))
1891 /* now wait for the write lock */
1892 LWLockAcquire(WALWriteLock
, LW_EXCLUSIVE
);
1893 LogwrtResult
= XLogCtl
->Write
.LogwrtResult
;
1894 if (!XLByteLE(record
, LogwrtResult
.Flush
))
1896 /* try to write/flush later additions to XLOG as well */
1897 if (LWLockConditionalAcquire(WALInsertLock
, LW_EXCLUSIVE
))
1899 XLogCtlInsert
*Insert
= &XLogCtl
->Insert
;
1900 uint32 freespace
= INSERT_FREESPACE(Insert
);
1902 if (freespace
< SizeOfXLogRecord
) /* buffer is full */
1903 WriteRqstPtr
= XLogCtl
->xlblocks
[Insert
->curridx
];
1906 WriteRqstPtr
= XLogCtl
->xlblocks
[Insert
->curridx
];
1907 WriteRqstPtr
.xrecoff
-= freespace
;
1909 LWLockRelease(WALInsertLock
);
1910 WriteRqst
.Write
= WriteRqstPtr
;
1911 WriteRqst
.Flush
= WriteRqstPtr
;
1915 WriteRqst
.Write
= WriteRqstPtr
;
1916 WriteRqst
.Flush
= record
;
1918 XLogWrite(WriteRqst
, false, false);
1920 LWLockRelease(WALWriteLock
);
1926 * If we still haven't flushed to the request point then we have a
1927 * problem; most likely, the requested flush point is past end of XLOG.
1928 * This has been seen to occur when a disk page has a corrupted LSN.
1930 * Formerly we treated this as a PANIC condition, but that hurts the
1931 * system's robustness rather than helping it: we do not want to take down
1932 * the whole system due to corruption on one data page. In particular, if
1933 * the bad page is encountered again during recovery then we would be
1934 * unable to restart the database at all! (This scenario has actually
1935 * happened in the field several times with 7.1 releases. Note that we
1936 * cannot get here while RecoveryInProgress(), but if the bad page is
1937 * brought in and marked dirty during recovery then if a checkpoint were
1938 * performed at the end of recovery it will try to flush it.
1940 * The current approach is to ERROR under normal conditions, but only
1941 * WARNING during recovery, so that the system can be brought up even if
1942 * there's a corrupt LSN. Note that for calls from xact.c, the ERROR will
1943 * be promoted to PANIC since xact.c calls this routine inside a critical
1944 * section. However, calls from bufmgr.c are not within critical sections
1945 * and so we will not force a restart for a bad LSN on a data page.
1947 if (XLByteLT(LogwrtResult
.Flush
, record
))
1948 elog(InRecovery
? WARNING
: ERROR
,
1949 "xlog flush request %X/%X is not satisfied --- flushed only to %X/%X",
1950 record
.xlogid
, record
.xrecoff
,
1951 LogwrtResult
.Flush
.xlogid
, LogwrtResult
.Flush
.xrecoff
);
1955 * Flush xlog, but without specifying exactly where to flush to.
1957 * We normally flush only completed blocks; but if there is nothing to do on
1958 * that basis, we check for unflushed async commits in the current incomplete
1959 * block, and flush through the latest one of those. Thus, if async commits
1960 * are not being used, we will flush complete blocks only. We can guarantee
1961 * that async commits reach disk after at most three cycles; normally only
1962 * one or two. (We allow XLogWrite to write "flexibly", meaning it can stop
1963 * at the end of the buffer ring; this makes a difference only with very high
1964 * load or long wal_writer_delay, but imposes one extra cycle for the worst
1965 * case for async commits.)
1967 * This routine is invoked periodically by the background walwriter process.
1970 XLogBackgroundFlush(void)
1972 XLogRecPtr WriteRqstPtr
;
1973 bool flexible
= true;
1975 /* XLOG doesn't need flushing during recovery */
1976 if (RecoveryInProgress())
1979 /* read LogwrtResult and update local state */
1981 /* use volatile pointer to prevent code rearrangement */
1982 volatile XLogCtlData
*xlogctl
= XLogCtl
;
1984 SpinLockAcquire(&xlogctl
->info_lck
);
1985 LogwrtResult
= xlogctl
->LogwrtResult
;
1986 WriteRqstPtr
= xlogctl
->LogwrtRqst
.Write
;
1987 SpinLockRelease(&xlogctl
->info_lck
);
1990 /* back off to last completed page boundary */
1991 WriteRqstPtr
.xrecoff
-= WriteRqstPtr
.xrecoff
% XLOG_BLCKSZ
;
1993 /* if we have already flushed that far, consider async commit records */
1994 if (XLByteLE(WriteRqstPtr
, LogwrtResult
.Flush
))
1996 /* use volatile pointer to prevent code rearrangement */
1997 volatile XLogCtlData
*xlogctl
= XLogCtl
;
1999 SpinLockAcquire(&xlogctl
->info_lck
);
2000 WriteRqstPtr
= xlogctl
->asyncCommitLSN
;
2001 SpinLockRelease(&xlogctl
->info_lck
);
2002 flexible
= false; /* ensure it all gets written */
2005 /* Done if already known flushed */
2006 if (XLByteLE(WriteRqstPtr
, LogwrtResult
.Flush
))
2011 elog(LOG
, "xlog bg flush request %X/%X; write %X/%X; flush %X/%X",
2012 WriteRqstPtr
.xlogid
, WriteRqstPtr
.xrecoff
,
2013 LogwrtResult
.Write
.xlogid
, LogwrtResult
.Write
.xrecoff
,
2014 LogwrtResult
.Flush
.xlogid
, LogwrtResult
.Flush
.xrecoff
);
2017 START_CRIT_SECTION();
2019 /* now wait for the write lock */
2020 LWLockAcquire(WALWriteLock
, LW_EXCLUSIVE
);
2021 LogwrtResult
= XLogCtl
->Write
.LogwrtResult
;
2022 if (!XLByteLE(WriteRqstPtr
, LogwrtResult
.Flush
))
2024 XLogwrtRqst WriteRqst
;
2026 WriteRqst
.Write
= WriteRqstPtr
;
2027 WriteRqst
.Flush
= WriteRqstPtr
;
2028 XLogWrite(WriteRqst
, flexible
, false);
2030 LWLockRelease(WALWriteLock
);
2036 * Flush any previous asynchronously-committed transactions' commit records.
2038 * NOTE: it is unwise to assume that this provides any strong guarantees.
2039 * In particular, because of the inexact LSN bookkeeping used by clog.c,
2040 * we cannot assume that hint bits will be settable for these transactions.
2043 XLogAsyncCommitFlush(void)
2045 XLogRecPtr WriteRqstPtr
;
2047 /* use volatile pointer to prevent code rearrangement */
2048 volatile XLogCtlData
*xlogctl
= XLogCtl
;
2050 /* There's no asynchronously committed transactions during recovery */
2051 if (RecoveryInProgress())
2054 SpinLockAcquire(&xlogctl
->info_lck
);
2055 WriteRqstPtr
= xlogctl
->asyncCommitLSN
;
2056 SpinLockRelease(&xlogctl
->info_lck
);
2058 XLogFlush(WriteRqstPtr
);
2062 * Test whether XLOG data has been flushed up to (at least) the given position.
2064 * Returns true if a flush is still needed. (It may be that someone else
2065 * is already in process of flushing that far, however.)
2068 XLogNeedsFlush(XLogRecPtr record
)
2070 /* XLOG doesn't need flushing during recovery */
2071 if (RecoveryInProgress())
2074 /* Quick exit if already known flushed */
2075 if (XLByteLE(record
, LogwrtResult
.Flush
))
2078 /* read LogwrtResult and update local state */
2080 /* use volatile pointer to prevent code rearrangement */
2081 volatile XLogCtlData
*xlogctl
= XLogCtl
;
2083 SpinLockAcquire(&xlogctl
->info_lck
);
2084 LogwrtResult
= xlogctl
->LogwrtResult
;
2085 SpinLockRelease(&xlogctl
->info_lck
);
2089 if (XLByteLE(record
, LogwrtResult
.Flush
))
2096 * Create a new XLOG file segment, or open a pre-existing one.
2098 * log, seg: identify segment to be created/opened.
2100 * *use_existent: if TRUE, OK to use a pre-existing file (else, any
2101 * pre-existing file will be deleted). On return, TRUE if a pre-existing
2104 * use_lock: if TRUE, acquire ControlFileLock while moving file into
2105 * place. This should be TRUE except during bootstrap log creation. The
2106 * caller must *not* hold the lock at call.
2108 * Returns FD of opened file.
2110 * Note: errors here are ERROR not PANIC because we might or might not be
2111 * inside a critical section (eg, during checkpoint there is no reason to
2112 * take down the system on failure). They will promote to PANIC if we are
2113 * in a critical section.
2116 XLogFileInit(uint32 log
, uint32 seg
,
2117 bool *use_existent
, bool use_lock
)
2119 char path
[MAXPGPATH
];
2120 char tmppath
[MAXPGPATH
];
2122 uint32 installed_log
;
2123 uint32 installed_seg
;
2128 XLogFilePath(path
, ThisTimeLineID
, log
, seg
);
2131 * Try to use existent file (checkpoint maker may have created it already)
2135 fd
= BasicOpenFile(path
, O_RDWR
| PG_BINARY
| get_sync_bit(sync_method
),
2139 if (errno
!= ENOENT
)
2141 (errcode_for_file_access(),
2142 errmsg("could not open file \"%s\" (log file %u, segment %u): %m",
2150 * Initialize an empty (all zeroes) segment. NOTE: it is possible that
2151 * another process is doing the same thing. If so, we will end up
2152 * pre-creating an extra log segment. That seems OK, and better than
2153 * holding the lock throughout this lengthy process.
2155 elog(DEBUG2
, "creating and filling new WAL file");
2157 snprintf(tmppath
, MAXPGPATH
, XLOGDIR
"/xlogtemp.%d", (int) getpid());
2161 /* do not use get_sync_bit() here --- want to fsync only at end of fill */
2162 fd
= BasicOpenFile(tmppath
, O_RDWR
| O_CREAT
| O_EXCL
| PG_BINARY
,
2166 (errcode_for_file_access(),
2167 errmsg("could not create file \"%s\": %m", tmppath
)));
2170 * Zero-fill the file. We have to do this the hard way to ensure that all
2171 * the file space has really been allocated --- on platforms that allow
2172 * "holes" in files, just seeking to the end doesn't allocate intermediate
2173 * space. This way, we know that we have all the space and (after the
2174 * fsync below) that all the indirect blocks are down on disk. Therefore,
2175 * fdatasync(2) or O_DSYNC will be sufficient to sync future writes to the
2178 * Note: palloc zbuffer, instead of just using a local char array, to
2179 * ensure it is reasonably well-aligned; this may save a few cycles
2180 * transferring data to the kernel.
2182 zbuffer
= (char *) palloc0(XLOG_BLCKSZ
);
2183 for (nbytes
= 0; nbytes
< XLogSegSize
; nbytes
+= XLOG_BLCKSZ
)
2186 if ((int) write(fd
, zbuffer
, XLOG_BLCKSZ
) != (int) XLOG_BLCKSZ
)
2188 int save_errno
= errno
;
2191 * If we fail to make the file, delete it to release disk space
2194 /* if write didn't set errno, assume problem is no disk space */
2195 errno
= save_errno
? save_errno
: ENOSPC
;
2198 (errcode_for_file_access(),
2199 errmsg("could not write to file \"%s\": %m", tmppath
)));
2204 if (pg_fsync(fd
) != 0)
2206 (errcode_for_file_access(),
2207 errmsg("could not fsync file \"%s\": %m", tmppath
)));
2211 (errcode_for_file_access(),
2212 errmsg("could not close file \"%s\": %m", tmppath
)));
2215 * Now move the segment into place with its final name.
2217 * If caller didn't want to use a pre-existing file, get rid of any
2218 * pre-existing file. Otherwise, cope with possibility that someone else
2219 * has created the file while we were filling ours: if so, use ours to
2220 * pre-create a future log segment.
2222 installed_log
= log
;
2223 installed_seg
= seg
;
2224 max_advance
= XLOGfileslop
;
2225 if (!InstallXLogFileSegment(&installed_log
, &installed_seg
, tmppath
,
2226 *use_existent
, &max_advance
,
2229 /* No need for any more future segments... */
2233 elog(DEBUG2
, "done creating and filling new WAL file");
2235 /* Set flag to tell caller there was no existent file */
2236 *use_existent
= false;
2238 /* Now open original target segment (might not be file I just made) */
2239 fd
= BasicOpenFile(path
, O_RDWR
| PG_BINARY
| get_sync_bit(sync_method
),
2243 (errcode_for_file_access(),
2244 errmsg("could not open file \"%s\" (log file %u, segment %u): %m",
2251 * Create a new XLOG file segment by copying a pre-existing one.
2253 * log, seg: identify segment to be created.
2255 * srcTLI, srclog, srcseg: identify segment to be copied (could be from
2256 * a different timeline)
2258 * Currently this is only used during recovery, and so there are no locking
2259 * considerations. But we should be just as tense as XLogFileInit to avoid
2260 * emplacing a bogus file.
2263 XLogFileCopy(uint32 log
, uint32 seg
,
2264 TimeLineID srcTLI
, uint32 srclog
, uint32 srcseg
)
2266 char path
[MAXPGPATH
];
2267 char tmppath
[MAXPGPATH
];
2268 char buffer
[XLOG_BLCKSZ
];
2274 * Open the source file
2276 XLogFilePath(path
, srcTLI
, srclog
, srcseg
);
2277 srcfd
= BasicOpenFile(path
, O_RDONLY
| PG_BINARY
, 0);
2280 (errcode_for_file_access(),
2281 errmsg("could not open file \"%s\": %m", path
)));
2284 * Copy into a temp file name.
2286 snprintf(tmppath
, MAXPGPATH
, XLOGDIR
"/xlogtemp.%d", (int) getpid());
2290 /* do not use get_sync_bit() here --- want to fsync only at end of fill */
2291 fd
= BasicOpenFile(tmppath
, O_RDWR
| O_CREAT
| O_EXCL
| PG_BINARY
,
2295 (errcode_for_file_access(),
2296 errmsg("could not create file \"%s\": %m", tmppath
)));
2299 * Do the data copying.
2301 for (nbytes
= 0; nbytes
< XLogSegSize
; nbytes
+= sizeof(buffer
))
2304 if ((int) read(srcfd
, buffer
, sizeof(buffer
)) != (int) sizeof(buffer
))
2308 (errcode_for_file_access(),
2309 errmsg("could not read file \"%s\": %m", path
)));
2312 (errmsg("not enough data in file \"%s\"", path
)));
2315 if ((int) write(fd
, buffer
, sizeof(buffer
)) != (int) sizeof(buffer
))
2317 int save_errno
= errno
;
2320 * If we fail to make the file, delete it to release disk space
2323 /* if write didn't set errno, assume problem is no disk space */
2324 errno
= save_errno
? save_errno
: ENOSPC
;
2327 (errcode_for_file_access(),
2328 errmsg("could not write to file \"%s\": %m", tmppath
)));
2332 if (pg_fsync(fd
) != 0)
2334 (errcode_for_file_access(),
2335 errmsg("could not fsync file \"%s\": %m", tmppath
)));
2339 (errcode_for_file_access(),
2340 errmsg("could not close file \"%s\": %m", tmppath
)));
2345 * Now move the segment into place with its final name.
2347 if (!InstallXLogFileSegment(&log
, &seg
, tmppath
, false, NULL
, false))
2348 elog(ERROR
, "InstallXLogFileSegment should not have failed");
2352 * Install a new XLOG segment file as a current or future log segment.
2354 * This is used both to install a newly-created segment (which has a temp
2355 * filename while it's being created) and to recycle an old segment.
2357 * *log, *seg: identify segment to install as (or first possible target).
2358 * When find_free is TRUE, these are modified on return to indicate the
2359 * actual installation location or last segment searched.
2361 * tmppath: initial name of file to install. It will be renamed into place.
2363 * find_free: if TRUE, install the new segment at the first empty log/seg
2364 * number at or after the passed numbers. If FALSE, install the new segment
2365 * exactly where specified, deleting any existing segment file there.
2367 * *max_advance: maximum number of log/seg slots to advance past the starting
2368 * point. Fail if no free slot is found in this range. On return, reduced
2369 * by the number of slots skipped over. (Irrelevant, and may be NULL,
2370 * when find_free is FALSE.)
2372 * use_lock: if TRUE, acquire ControlFileLock while moving file into
2373 * place. This should be TRUE except during bootstrap log creation. The
2374 * caller must *not* hold the lock at call.
2376 * Returns TRUE if file installed, FALSE if not installed because of
2377 * exceeding max_advance limit. On Windows, we also return FALSE if we
2378 * can't rename the file into place because someone's got it open.
2379 * (Any other kind of failure causes ereport().)
2382 InstallXLogFileSegment(uint32
*log
, uint32
*seg
, char *tmppath
,
2383 bool find_free
, int *max_advance
,
2386 char path
[MAXPGPATH
];
2387 struct stat stat_buf
;
2389 XLogFilePath(path
, ThisTimeLineID
, *log
, *seg
);
2392 * We want to be sure that only one process does this at a time.
2395 LWLockAcquire(ControlFileLock
, LW_EXCLUSIVE
);
2399 /* Force installation: get rid of any pre-existing segment file */
2404 /* Find a free slot to put it in */
2405 while (stat(path
, &stat_buf
) == 0)
2407 if (*max_advance
<= 0)
2409 /* Failed to find a free slot within specified range */
2411 LWLockRelease(ControlFileLock
);
2414 NextLogSeg(*log
, *seg
);
2416 XLogFilePath(path
, ThisTimeLineID
, *log
, *seg
);
2421 * Prefer link() to rename() here just to be really sure that we don't
2422 * overwrite an existing logfile. However, there shouldn't be one, so
2423 * rename() is an acceptable substitute except for the truly paranoid.
2425 #if HAVE_WORKING_LINK
2426 if (link(tmppath
, path
) < 0)
2428 (errcode_for_file_access(),
2429 errmsg("could not link file \"%s\" to \"%s\" (initialization of log file %u, segment %u): %m",
2430 tmppath
, path
, *log
, *seg
)));
2433 if (rename(tmppath
, path
) < 0)
2436 #if !defined(__CYGWIN__)
2437 if (GetLastError() == ERROR_ACCESS_DENIED
)
2439 if (errno
== EACCES
)
2443 LWLockRelease(ControlFileLock
);
2449 (errcode_for_file_access(),
2450 errmsg("could not rename file \"%s\" to \"%s\" (initialization of log file %u, segment %u): %m",
2451 tmppath
, path
, *log
, *seg
)));
2456 LWLockRelease(ControlFileLock
);
2462 * Open a pre-existing logfile segment for writing.
2465 XLogFileOpen(uint32 log
, uint32 seg
)
2467 char path
[MAXPGPATH
];
2470 XLogFilePath(path
, ThisTimeLineID
, log
, seg
);
2472 fd
= BasicOpenFile(path
, O_RDWR
| PG_BINARY
| get_sync_bit(sync_method
),
2476 (errcode_for_file_access(),
2477 errmsg("could not open file \"%s\" (log file %u, segment %u): %m",
2484 * Open a logfile segment for reading (during recovery).
2487 XLogFileRead(uint32 log
, uint32 seg
, int emode
)
2489 char path
[MAXPGPATH
];
2490 char xlogfname
[MAXFNAMELEN
];
2491 char activitymsg
[MAXFNAMELEN
+ 16];
2496 * Loop looking for a suitable timeline ID: we might need to read any of
2497 * the timelines listed in expectedTLIs.
2499 * We expect curFileTLI on entry to be the TLI of the preceding file in
2500 * sequence, or 0 if there was no predecessor. We do not allow curFileTLI
2501 * to go backwards; this prevents us from picking up the wrong file when a
2502 * parent timeline extends to higher segment numbers than the child we
2505 foreach(cell
, expectedTLIs
)
2507 TimeLineID tli
= (TimeLineID
) lfirst_int(cell
);
2509 if (tli
< curFileTLI
)
2510 break; /* don't bother looking at too-old TLIs */
2512 XLogFileName(xlogfname
, tli
, log
, seg
);
2514 if (InArchiveRecovery
)
2516 /* Report recovery progress in PS display */
2517 snprintf(activitymsg
, sizeof(activitymsg
), "waiting for %s",
2519 set_ps_display(activitymsg
, false);
2521 restoredFromArchive
= RestoreArchivedFile(path
, xlogfname
,
2526 XLogFilePath(path
, tli
, log
, seg
);
2528 fd
= BasicOpenFile(path
, O_RDONLY
| PG_BINARY
, 0);
2534 /* Report recovery progress in PS display */
2535 snprintf(activitymsg
, sizeof(activitymsg
), "recovering %s",
2537 set_ps_display(activitymsg
, false);
2541 if (errno
!= ENOENT
) /* unexpected failure? */
2543 (errcode_for_file_access(),
2544 errmsg("could not open file \"%s\" (log file %u, segment %u): %m",
2548 /* Couldn't find it. For simplicity, complain about front timeline */
2549 XLogFilePath(path
, recoveryTargetTLI
, log
, seg
);
2552 (errcode_for_file_access(),
2553 errmsg("could not open file \"%s\" (log file %u, segment %u): %m",
2559 * Close the current logfile segment for writing.
2564 Assert(openLogFile
>= 0);
2567 * WAL segment files will not be re-read in normal operation, so we advise
2568 * the OS to release any cached pages. But do not do so if WAL archiving
2569 * is active, because archiver process could use the cache to read the WAL
2570 * segment. Also, don't bother with it if we are using O_DIRECT, since
2571 * the kernel is presumably not caching in that case.
2573 #if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
2574 if (!XLogArchivingActive() &&
2575 (get_sync_bit(sync_method
) & PG_O_DIRECT
) == 0)
2576 (void) posix_fadvise(openLogFile
, 0, 0, POSIX_FADV_DONTNEED
);
2579 if (close(openLogFile
))
2581 (errcode_for_file_access(),
2582 errmsg("could not close log file %u, segment %u: %m",
2583 openLogId
, openLogSeg
)));
2588 * Attempt to retrieve the specified file from off-line archival storage.
2589 * If successful, fill "path" with its complete path (note that this will be
2590 * a temp file name that doesn't follow the normal naming convention), and
2593 * If not successful, fill "path" with the name of the normal on-line file
2594 * (which may or may not actually exist, but we'll try to use it), and return
2597 * For fixed-size files, the caller may pass the expected size as an
2598 * additional crosscheck on successful recovery. If the file size is not
2599 * known, set expectedSize = 0.
2602 RestoreArchivedFile(char *path
, const char *xlogfname
,
2603 const char *recovername
, off_t expectedSize
)
2605 char xlogpath
[MAXPGPATH
];
2606 char xlogRestoreCmd
[MAXPGPATH
];
2607 char lastRestartPointFname
[MAXPGPATH
];
2613 struct stat stat_buf
;
2618 * When doing archive recovery, we always prefer an archived log file even
2619 * if a file of the same name exists in XLOGDIR. The reason is that the
2620 * file in XLOGDIR could be an old, un-filled or partly-filled version
2621 * that was copied and restored as part of backing up $PGDATA.
2623 * We could try to optimize this slightly by checking the local copy
2624 * lastchange timestamp against the archived copy, but we have no API to
2625 * do this, nor can we guarantee that the lastchange timestamp was
2626 * preserved correctly when we copied to archive. Our aim is robustness,
2627 * so we elect not to do this.
2629 * If we cannot obtain the log file from the archive, however, we will try
2630 * to use the XLOGDIR file if it exists. This is so that we can make use
2631 * of log segments that weren't yet transferred to the archive.
2633 * Notice that we don't actually overwrite any files when we copy back
2634 * from archive because the recoveryRestoreCommand may inadvertently
2635 * restore inappropriate xlogs, or they may be corrupt, so we may wish to
2636 * fallback to the segments remaining in current XLOGDIR later. The
2637 * copy-from-archive filename is always the same, ensuring that we don't
2638 * run out of disk space on long recoveries.
2640 snprintf(xlogpath
, MAXPGPATH
, XLOGDIR
"/%s", recovername
);
2643 * Make sure there is no existing file named recovername.
2645 if (stat(xlogpath
, &stat_buf
) != 0)
2647 if (errno
!= ENOENT
)
2649 (errcode_for_file_access(),
2650 errmsg("could not stat file \"%s\": %m",
2655 if (unlink(xlogpath
) != 0)
2657 (errcode_for_file_access(),
2658 errmsg("could not remove file \"%s\": %m",
2663 * Calculate the archive file cutoff point for use during log shipping
2664 * replication. All files earlier than this point can be deleted
2665 * from the archive, though there is no requirement to do so.
2667 * We initialise this with the filename of an InvalidXLogRecPtr, which
2668 * will prevent the deletion of any WAL files from the archive
2669 * because of the alphabetic sorting property of WAL filenames.
2671 * Once we have successfully located the redo pointer of the checkpoint
2672 * from which we start recovery we never request a file prior to the redo
2673 * pointer of the last restartpoint. When redo begins we know that we
2674 * have successfully located it, so there is no need for additional
2675 * status flags to signify the point when we can begin deleting WAL files
2680 XLByteToSeg(ControlFile
->checkPointCopy
.redo
,
2681 restartLog
, restartSeg
);
2682 XLogFileName(lastRestartPointFname
,
2683 ControlFile
->checkPointCopy
.ThisTimeLineID
,
2684 restartLog
, restartSeg
);
2685 /* we shouldn't need anything earlier than last restart point */
2686 Assert(strcmp(lastRestartPointFname
, xlogfname
) <= 0);
2689 XLogFileName(lastRestartPointFname
, 0, 0, 0);
2692 * construct the command to be executed
2694 dp
= xlogRestoreCmd
;
2695 endp
= xlogRestoreCmd
+ MAXPGPATH
- 1;
2698 for (sp
= recoveryRestoreCommand
; *sp
; sp
++)
2705 /* %p: relative path of target file */
2707 StrNCpy(dp
, xlogpath
, endp
- dp
);
2708 make_native_path(dp
);
2712 /* %f: filename of desired file */
2714 StrNCpy(dp
, xlogfname
, endp
- dp
);
2718 /* %r: filename of last restartpoint */
2720 StrNCpy(dp
, lastRestartPointFname
, endp
- dp
);
2724 /* convert %% to a single % */
2730 /* otherwise treat the % as not special */
2745 (errmsg_internal("executing restore command \"%s\"",
2749 * Set in_restore_command to tell the signal handler that we should exit
2750 * right away on SIGTERM. We know that we're in a safe point to do that.
2751 * Check if we had already received the signal, so that we don't miss a
2752 * shutdown request received just before this.
2754 in_restore_command
= true;
2755 if (shutdown_requested
)
2759 * Copy xlog from archival storage to XLOGDIR
2761 rc
= system(xlogRestoreCmd
);
2763 in_restore_command
= false;
2768 * command apparently succeeded, but let's make sure the file is
2769 * really there now and has the correct size.
2771 * XXX I made wrong-size a fatal error to ensure the DBA would notice
2772 * it, but is that too strong? We could try to plow ahead with a
2773 * local copy of the file ... but the problem is that there probably
2774 * isn't one, and we'd incorrectly conclude we've reached the end of
2775 * WAL and we're done recovering ...
2777 if (stat(xlogpath
, &stat_buf
) == 0)
2779 if (expectedSize
> 0 && stat_buf
.st_size
!= expectedSize
)
2781 (errmsg("archive file \"%s\" has wrong size: %lu instead of %lu",
2783 (unsigned long) stat_buf
.st_size
,
2784 (unsigned long) expectedSize
)));
2788 (errmsg("restored log file \"%s\" from archive",
2790 strcpy(path
, xlogpath
);
2797 if (errno
!= ENOENT
)
2799 (errcode_for_file_access(),
2800 errmsg("could not stat file \"%s\": %m",
2806 * Remember, we rollforward UNTIL the restore fails so failure here is
2807 * just part of the process... that makes it difficult to determine
2808 * whether the restore failed because there isn't an archive to restore,
2809 * or because the administrator has specified the restore program
2810 * incorrectly. We have to assume the former.
2812 * However, if the failure was due to any sort of signal, it's best to
2813 * punt and abort recovery. (If we "return false" here, upper levels will
2814 * assume that recovery is complete and start up the database!) It's
2815 * essential to abort on child SIGINT and SIGQUIT, because per spec
2816 * system() ignores SIGINT and SIGQUIT while waiting; if we see one of
2817 * those it's a good bet we should have gotten it too.
2819 * On SIGTERM, assume we have received a fast shutdown request, and exit
2820 * cleanly. It's pure chance whether we receive the SIGTERM first, or the
2821 * child process. If we receive it first, the signal handler will call
2822 * proc_exit, otherwise we do it here. If we or the child process
2823 * received SIGTERM for any other reason than a fast shutdown request,
2824 * postmaster will perform an immediate shutdown when it sees us exiting
2827 * Per the Single Unix Spec, shells report exit status > 128 when a called
2828 * command died on a signal. Also, 126 and 127 are used to report
2829 * problems such as an unfindable command; treat those as fatal errors
2832 if (WTERMSIG(rc
) == SIGTERM
)
2835 signaled
= WIFSIGNALED(rc
) || WEXITSTATUS(rc
) > 125;
2837 ereport(signaled
? FATAL
: DEBUG2
,
2838 (errmsg("could not restore file \"%s\" from archive: return code %d",
2842 * if an archived file is not available, there might still be a version of
2843 * this file in XLOGDIR, so return that as the filename to open.
2845 * In many recovery scenarios we expect this to fail also, but if so that
2846 * just means we've reached the end of WAL.
2848 snprintf(path
, MAXPGPATH
, XLOGDIR
"/%s", xlogfname
);
2853 * Preallocate log files beyond the specified log endpoint.
2855 * XXX this is currently extremely conservative, since it forces only one
2856 * future log segment to exist, and even that only if we are 75% done with
2857 * the current one. This is only appropriate for very low-WAL-volume systems.
2858 * High-volume systems will be OK once they've built up a sufficient set of
2859 * recycled log segments, but the startup transient is likely to include
2860 * a lot of segment creations by foreground processes, which is not so good.
2863 PreallocXlogFiles(XLogRecPtr endptr
)
2870 XLByteToPrevSeg(endptr
, _logId
, _logSeg
);
2871 if ((endptr
.xrecoff
- 1) % XLogSegSize
>=
2872 (uint32
) (0.75 * XLogSegSize
))
2874 NextLogSeg(_logId
, _logSeg
);
2875 use_existent
= true;
2876 lf
= XLogFileInit(_logId
, _logSeg
, &use_existent
, true);
2879 CheckpointStats
.ckpt_segs_added
++;
2884 * Recycle or remove all log files older or equal to passed log/seg#
2886 * endptr is current (or recent) end of xlog; this is used to determine
2887 * whether we want to recycle rather than delete no-longer-wanted log files.
2890 RemoveOldXlogFiles(uint32 log
, uint32 seg
, XLogRecPtr endptr
)
2896 struct dirent
*xlde
;
2897 char lastoff
[MAXFNAMELEN
];
2898 char path
[MAXPGPATH
];
2901 * Initialize info about where to try to recycle to. We allow recycling
2902 * segments up to XLOGfileslop segments beyond the current XLOG location.
2904 XLByteToPrevSeg(endptr
, endlogId
, endlogSeg
);
2905 max_advance
= XLOGfileslop
;
2907 xldir
= AllocateDir(XLOGDIR
);
2910 (errcode_for_file_access(),
2911 errmsg("could not open transaction log directory \"%s\": %m",
2914 XLogFileName(lastoff
, ThisTimeLineID
, log
, seg
);
2916 while ((xlde
= ReadDir(xldir
, XLOGDIR
)) != NULL
)
2919 * We ignore the timeline part of the XLOG segment identifiers in
2920 * deciding whether a segment is still needed. This ensures that we
2921 * won't prematurely remove a segment from a parent timeline. We could
2922 * probably be a little more proactive about removing segments of
2923 * non-parent timelines, but that would be a whole lot more
2926 * We use the alphanumeric sorting property of the filenames to decide
2927 * which ones are earlier than the lastoff segment.
2929 if (strlen(xlde
->d_name
) == 24 &&
2930 strspn(xlde
->d_name
, "0123456789ABCDEF") == 24 &&
2931 strcmp(xlde
->d_name
+ 8, lastoff
+ 8) <= 0)
2933 if (XLogArchiveCheckDone(xlde
->d_name
))
2935 snprintf(path
, MAXPGPATH
, XLOGDIR
"/%s", xlde
->d_name
);
2938 * Before deleting the file, see if it can be recycled as a
2939 * future log segment.
2941 if (InstallXLogFileSegment(&endlogId
, &endlogSeg
, path
,
2946 (errmsg("recycled transaction log file \"%s\"",
2948 CheckpointStats
.ckpt_segs_recycled
++;
2949 /* Needn't recheck that slot on future iterations */
2950 if (max_advance
> 0)
2952 NextLogSeg(endlogId
, endlogSeg
);
2958 /* No need for any more future segments... */
2960 (errmsg("removing transaction log file \"%s\"",
2963 CheckpointStats
.ckpt_segs_removed
++;
2966 XLogArchiveCleanup(xlde
->d_name
);
2975 * Verify whether pg_xlog and pg_xlog/archive_status exist.
2976 * If the latter does not exist, recreate it.
2978 * It is not the goal of this function to verify the contents of these
2979 * directories, but to help in cases where someone has performed a cluster
2980 * copy for PITR purposes but omitted pg_xlog from the copy.
2982 * We could also recreate pg_xlog if it doesn't exist, but a deliberate
2983 * policy decision was made not to. It is fairly common for pg_xlog to be
2984 * a symlink, and if that was the DBA's intent then automatically making a
2985 * plain directory would result in degraded performance with no notice.
2988 ValidateXLOGDirectoryStructure(void)
2990 char path
[MAXPGPATH
];
2991 struct stat stat_buf
;
2993 /* Check for pg_xlog; if it doesn't exist, error out */
2994 if (stat(XLOGDIR
, &stat_buf
) != 0 ||
2995 !S_ISDIR(stat_buf
.st_mode
))
2997 (errmsg("required WAL directory \"%s\" does not exist",
3000 /* Check for archive_status */
3001 snprintf(path
, MAXPGPATH
, XLOGDIR
"/archive_status");
3002 if (stat(path
, &stat_buf
) == 0)
3004 /* Check for weird cases where it exists but isn't a directory */
3005 if (!S_ISDIR(stat_buf
.st_mode
))
3007 (errmsg("required WAL directory \"%s\" does not exist",
3013 (errmsg("creating missing WAL directory \"%s\"", path
)));
3014 if (mkdir(path
, 0700) < 0)
3016 (errmsg("could not create missing directory \"%s\": %m",
3022 * Remove previous backup history files. This also retries creation of
3023 * .ready files for any backup history files for which XLogArchiveNotify
3027 CleanupBackupHistory(void)
3030 struct dirent
*xlde
;
3031 char path
[MAXPGPATH
];
3033 xldir
= AllocateDir(XLOGDIR
);
3036 (errcode_for_file_access(),
3037 errmsg("could not open transaction log directory \"%s\": %m",
3040 while ((xlde
= ReadDir(xldir
, XLOGDIR
)) != NULL
)
3042 if (strlen(xlde
->d_name
) > 24 &&
3043 strspn(xlde
->d_name
, "0123456789ABCDEF") == 24 &&
3044 strcmp(xlde
->d_name
+ strlen(xlde
->d_name
) - strlen(".backup"),
3047 if (XLogArchiveCheckDone(xlde
->d_name
))
3050 (errmsg("removing transaction log backup history file \"%s\"",
3052 snprintf(path
, MAXPGPATH
, XLOGDIR
"/%s", xlde
->d_name
);
3054 XLogArchiveCleanup(xlde
->d_name
);
3063 * Restore the backup blocks present in an XLOG record, if any.
3065 * We assume all of the record has been read into memory at *record.
3067 * Note: when a backup block is available in XLOG, we restore it
3068 * unconditionally, even if the page in the database appears newer.
3069 * This is to protect ourselves against database pages that were partially
3070 * or incorrectly written during a crash. We assume that the XLOG data
3071 * must be good because it has passed a CRC check, while the database
3072 * page might not be. This will force us to replay all subsequent
3073 * modifications of the page that appear in XLOG, rather than possibly
3074 * ignoring them as already applied, but that's not a huge drawback.
3076 * If 'cleanup' is true, a cleanup lock is used when restoring blocks.
3077 * Otherwise, a normal exclusive lock is used. At the moment, that's just
3078 * pro forma, because there can't be any regular backends in the system
3079 * during recovery. The 'cleanup' argument applies to all backup blocks
3080 * in the WAL record, that suffices for now.
3083 RestoreBkpBlocks(XLogRecPtr lsn
, XLogRecord
*record
, bool cleanup
)
3091 if (!(record
->xl_info
& XLR_BKP_BLOCK_MASK
))
3094 blk
= (char *) XLogRecGetData(record
) + record
->xl_len
;
3095 for (i
= 0; i
< XLR_MAX_BKP_BLOCKS
; i
++)
3097 if (!(record
->xl_info
& XLR_SET_BKP_BLOCK(i
)))
3100 memcpy(&bkpb
, blk
, sizeof(BkpBlock
));
3101 blk
+= sizeof(BkpBlock
);
3103 buffer
= XLogReadBufferExtended(bkpb
.node
, bkpb
.fork
, bkpb
.block
,
3105 Assert(BufferIsValid(buffer
));
3107 LockBufferForCleanup(buffer
);
3109 LockBuffer(buffer
, BUFFER_LOCK_EXCLUSIVE
);
3111 page
= (Page
) BufferGetPage(buffer
);
3113 if (bkpb
.hole_length
== 0)
3115 memcpy((char *) page
, blk
, BLCKSZ
);
3119 /* must zero-fill the hole */
3120 MemSet((char *) page
, 0, BLCKSZ
);
3121 memcpy((char *) page
, blk
, bkpb
.hole_offset
);
3122 memcpy((char *) page
+ (bkpb
.hole_offset
+ bkpb
.hole_length
),
3123 blk
+ bkpb
.hole_offset
,
3124 BLCKSZ
- (bkpb
.hole_offset
+ bkpb
.hole_length
));
3127 PageSetLSN(page
, lsn
);
3128 PageSetTLI(page
, ThisTimeLineID
);
3129 MarkBufferDirty(buffer
);
3130 UnlockReleaseBuffer(buffer
);
3132 blk
+= BLCKSZ
- bkpb
.hole_length
;
3137 * CRC-check an XLOG record. We do not believe the contents of an XLOG
3138 * record (other than to the minimal extent of computing the amount of
3139 * data to read in) until we've checked the CRCs.
3141 * We assume all of the record has been read into memory at *record.
3144 RecordIsValid(XLogRecord
*record
, XLogRecPtr recptr
, int emode
)
3148 uint32 len
= record
->xl_len
;
3152 /* First the rmgr data */
3154 COMP_CRC32(crc
, XLogRecGetData(record
), len
);
3156 /* Add in the backup blocks, if any */
3157 blk
= (char *) XLogRecGetData(record
) + len
;
3158 for (i
= 0; i
< XLR_MAX_BKP_BLOCKS
; i
++)
3162 if (!(record
->xl_info
& XLR_SET_BKP_BLOCK(i
)))
3165 memcpy(&bkpb
, blk
, sizeof(BkpBlock
));
3166 if (bkpb
.hole_offset
+ bkpb
.hole_length
> BLCKSZ
)
3169 (errmsg("incorrect hole size in record at %X/%X",
3170 recptr
.xlogid
, recptr
.xrecoff
)));
3173 blen
= sizeof(BkpBlock
) + BLCKSZ
- bkpb
.hole_length
;
3174 COMP_CRC32(crc
, blk
, blen
);
3178 /* Check that xl_tot_len agrees with our calculation */
3179 if (blk
!= (char *) record
+ record
->xl_tot_len
)
3182 (errmsg("incorrect total length in record at %X/%X",
3183 recptr
.xlogid
, recptr
.xrecoff
)));
3187 /* Finally include the record header */
3188 COMP_CRC32(crc
, (char *) record
+ sizeof(pg_crc32
),
3189 SizeOfXLogRecord
- sizeof(pg_crc32
));
3192 if (!EQ_CRC32(record
->xl_crc
, crc
))
3195 (errmsg("incorrect resource manager data checksum in record at %X/%X",
3196 recptr
.xlogid
, recptr
.xrecoff
)));
3204 * Attempt to read an XLOG record.
3206 * If RecPtr is not NULL, try to read a record at that position. Otherwise
3207 * try to read a record just after the last one previously read.
3209 * If no valid record is available, returns NULL, or fails if emode is PANIC.
3210 * (emode must be either PANIC or LOG.)
3212 * The record is copied into readRecordBuf, so that on successful return,
3213 * the returned record pointer always points there.
3216 ReadRecord(XLogRecPtr
*RecPtr
, int emode
)
3220 XLogRecPtr tmpRecPtr
= EndRecPtr
;
3221 bool randAccess
= false;
3224 uint32 targetPageOff
;
3225 uint32 targetRecOff
;
3226 uint32 pageHeaderSize
;
3228 if (readBuf
== NULL
)
3231 * First time through, permanently allocate readBuf. We do it this
3232 * way, rather than just making a static array, for two reasons: (1)
3233 * no need to waste the storage in most instantiations of the backend;
3234 * (2) a static char array isn't guaranteed to have any particular
3235 * alignment, whereas malloc() will provide MAXALIGN'd storage.
3237 readBuf
= (char *) malloc(XLOG_BLCKSZ
);
3238 Assert(readBuf
!= NULL
);
3243 RecPtr
= &tmpRecPtr
;
3244 /* fast case if next record is on same page */
3245 if (nextRecord
!= NULL
)
3247 record
= nextRecord
;
3250 /* align old recptr to next page */
3251 if (tmpRecPtr
.xrecoff
% XLOG_BLCKSZ
!= 0)
3252 tmpRecPtr
.xrecoff
+= (XLOG_BLCKSZ
- tmpRecPtr
.xrecoff
% XLOG_BLCKSZ
);
3253 if (tmpRecPtr
.xrecoff
>= XLogFileSize
)
3255 (tmpRecPtr
.xlogid
)++;
3256 tmpRecPtr
.xrecoff
= 0;
3258 /* We will account for page header size below */
3262 if (!XRecOffIsValid(RecPtr
->xrecoff
))
3264 (errmsg("invalid record offset at %X/%X",
3265 RecPtr
->xlogid
, RecPtr
->xrecoff
)));
3268 * Since we are going to a random position in WAL, forget any prior
3269 * state about what timeline we were in, and allow it to be any
3270 * timeline in expectedTLIs. We also set a flag to allow curFileTLI
3271 * to go backwards (but we can't reset that variable right here, since
3272 * we might not change files at all).
3274 lastPageTLI
= 0; /* see comment in ValidXLOGHeader */
3275 randAccess
= true; /* allow curFileTLI to go backwards too */
3278 if (readFile
>= 0 && !XLByteInSeg(*RecPtr
, readId
, readSeg
))
3283 XLByteToSeg(*RecPtr
, readId
, readSeg
);
3286 /* Now it's okay to reset curFileTLI if random fetch */
3290 readFile
= XLogFileRead(readId
, readSeg
, emode
);
3292 goto next_record_is_invalid
;
3295 * Whenever switching to a new WAL segment, we read the first page of
3296 * the file and validate its header, even if that's not where the
3297 * target record is. This is so that we can check the additional
3298 * identification info that is present in the first page's "long"
3302 if (read(readFile
, readBuf
, XLOG_BLCKSZ
) != XLOG_BLCKSZ
)
3305 (errcode_for_file_access(),
3306 errmsg("could not read from log file %u, segment %u, offset %u: %m",
3307 readId
, readSeg
, readOff
)));
3308 goto next_record_is_invalid
;
3310 if (!ValidXLOGHeader((XLogPageHeader
) readBuf
, emode
))
3311 goto next_record_is_invalid
;
3314 targetPageOff
= ((RecPtr
->xrecoff
% XLogSegSize
) / XLOG_BLCKSZ
) * XLOG_BLCKSZ
;
3315 if (readOff
!= targetPageOff
)
3317 readOff
= targetPageOff
;
3318 if (lseek(readFile
, (off_t
) readOff
, SEEK_SET
) < 0)
3321 (errcode_for_file_access(),
3322 errmsg("could not seek in log file %u, segment %u to offset %u: %m",
3323 readId
, readSeg
, readOff
)));
3324 goto next_record_is_invalid
;
3326 if (read(readFile
, readBuf
, XLOG_BLCKSZ
) != XLOG_BLCKSZ
)
3329 (errcode_for_file_access(),
3330 errmsg("could not read from log file %u, segment %u, offset %u: %m",
3331 readId
, readSeg
, readOff
)));
3332 goto next_record_is_invalid
;
3334 if (!ValidXLOGHeader((XLogPageHeader
) readBuf
, emode
))
3335 goto next_record_is_invalid
;
3337 pageHeaderSize
= XLogPageHeaderSize((XLogPageHeader
) readBuf
);
3338 targetRecOff
= RecPtr
->xrecoff
% XLOG_BLCKSZ
;
3339 if (targetRecOff
== 0)
3342 * Can only get here in the continuing-from-prev-page case, because
3343 * XRecOffIsValid eliminated the zero-page-offset case otherwise. Need
3344 * to skip over the new page's header.
3346 tmpRecPtr
.xrecoff
+= pageHeaderSize
;
3347 targetRecOff
= pageHeaderSize
;
3349 else if (targetRecOff
< pageHeaderSize
)
3352 (errmsg("invalid record offset at %X/%X",
3353 RecPtr
->xlogid
, RecPtr
->xrecoff
)));
3354 goto next_record_is_invalid
;
3356 if ((((XLogPageHeader
) readBuf
)->xlp_info
& XLP_FIRST_IS_CONTRECORD
) &&
3357 targetRecOff
== pageHeaderSize
)
3360 (errmsg("contrecord is requested by %X/%X",
3361 RecPtr
->xlogid
, RecPtr
->xrecoff
)));
3362 goto next_record_is_invalid
;
3364 record
= (XLogRecord
*) ((char *) readBuf
+ RecPtr
->xrecoff
% XLOG_BLCKSZ
);
3369 * xl_len == 0 is bad data for everything except XLOG SWITCH, where it is
3372 if (record
->xl_rmid
== RM_XLOG_ID
&& record
->xl_info
== XLOG_SWITCH
)
3374 if (record
->xl_len
!= 0)
3377 (errmsg("invalid xlog switch record at %X/%X",
3378 RecPtr
->xlogid
, RecPtr
->xrecoff
)));
3379 goto next_record_is_invalid
;
3382 else if (record
->xl_len
== 0)
3385 (errmsg("record with zero length at %X/%X",
3386 RecPtr
->xlogid
, RecPtr
->xrecoff
)));
3387 goto next_record_is_invalid
;
3389 if (record
->xl_tot_len
< SizeOfXLogRecord
+ record
->xl_len
||
3390 record
->xl_tot_len
> SizeOfXLogRecord
+ record
->xl_len
+
3391 XLR_MAX_BKP_BLOCKS
* (sizeof(BkpBlock
) + BLCKSZ
))
3394 (errmsg("invalid record length at %X/%X",
3395 RecPtr
->xlogid
, RecPtr
->xrecoff
)));
3396 goto next_record_is_invalid
;
3398 if (record
->xl_rmid
> RM_MAX_ID
)
3401 (errmsg("invalid resource manager ID %u at %X/%X",
3402 record
->xl_rmid
, RecPtr
->xlogid
, RecPtr
->xrecoff
)));
3403 goto next_record_is_invalid
;
3408 * We can't exactly verify the prev-link, but surely it should be less
3409 * than the record's own address.
3411 if (!XLByteLT(record
->xl_prev
, *RecPtr
))
3414 (errmsg("record with incorrect prev-link %X/%X at %X/%X",
3415 record
->xl_prev
.xlogid
, record
->xl_prev
.xrecoff
,
3416 RecPtr
->xlogid
, RecPtr
->xrecoff
)));
3417 goto next_record_is_invalid
;
3423 * Record's prev-link should exactly match our previous location. This
3424 * check guards against torn WAL pages where a stale but valid-looking
3425 * WAL record starts on a sector boundary.
3427 if (!XLByteEQ(record
->xl_prev
, ReadRecPtr
))
3430 (errmsg("record with incorrect prev-link %X/%X at %X/%X",
3431 record
->xl_prev
.xlogid
, record
->xl_prev
.xrecoff
,
3432 RecPtr
->xlogid
, RecPtr
->xrecoff
)));
3433 goto next_record_is_invalid
;
3438 * Allocate or enlarge readRecordBuf as needed. To avoid useless small
3439 * increases, round its size to a multiple of XLOG_BLCKSZ, and make sure
3440 * it's at least 4*Max(BLCKSZ, XLOG_BLCKSZ) to start with. (That is
3441 * enough for all "normal" records, but very large commit or abort records
3442 * might need more space.)
3444 total_len
= record
->xl_tot_len
;
3445 if (total_len
> readRecordBufSize
)
3447 uint32 newSize
= total_len
;
3449 newSize
+= XLOG_BLCKSZ
- (newSize
% XLOG_BLCKSZ
);
3450 newSize
= Max(newSize
, 4 * Max(BLCKSZ
, XLOG_BLCKSZ
));
3452 free(readRecordBuf
);
3453 readRecordBuf
= (char *) malloc(newSize
);
3456 readRecordBufSize
= 0;
3457 /* We treat this as a "bogus data" condition */
3459 (errmsg("record length %u at %X/%X too long",
3460 total_len
, RecPtr
->xlogid
, RecPtr
->xrecoff
)));
3461 goto next_record_is_invalid
;
3463 readRecordBufSize
= newSize
;
3466 buffer
= readRecordBuf
;
3468 len
= XLOG_BLCKSZ
- RecPtr
->xrecoff
% XLOG_BLCKSZ
;
3469 if (total_len
> len
)
3471 /* Need to reassemble record */
3472 XLogContRecord
*contrecord
;
3473 uint32 gotlen
= len
;
3475 memcpy(buffer
, record
, len
);
3476 record
= (XLogRecord
*) buffer
;
3480 readOff
+= XLOG_BLCKSZ
;
3481 if (readOff
>= XLogSegSize
)
3485 NextLogSeg(readId
, readSeg
);
3486 readFile
= XLogFileRead(readId
, readSeg
, emode
);
3488 goto next_record_is_invalid
;
3491 if (read(readFile
, readBuf
, XLOG_BLCKSZ
) != XLOG_BLCKSZ
)
3494 (errcode_for_file_access(),
3495 errmsg("could not read from log file %u, segment %u, offset %u: %m",
3496 readId
, readSeg
, readOff
)));
3497 goto next_record_is_invalid
;
3499 if (!ValidXLOGHeader((XLogPageHeader
) readBuf
, emode
))
3500 goto next_record_is_invalid
;
3501 if (!(((XLogPageHeader
) readBuf
)->xlp_info
& XLP_FIRST_IS_CONTRECORD
))
3504 (errmsg("there is no contrecord flag in log file %u, segment %u, offset %u",
3505 readId
, readSeg
, readOff
)));
3506 goto next_record_is_invalid
;
3508 pageHeaderSize
= XLogPageHeaderSize((XLogPageHeader
) readBuf
);
3509 contrecord
= (XLogContRecord
*) ((char *) readBuf
+ pageHeaderSize
);
3510 if (contrecord
->xl_rem_len
== 0 ||
3511 total_len
!= (contrecord
->xl_rem_len
+ gotlen
))
3514 (errmsg("invalid contrecord length %u in log file %u, segment %u, offset %u",
3515 contrecord
->xl_rem_len
,
3516 readId
, readSeg
, readOff
)));
3517 goto next_record_is_invalid
;
3519 len
= XLOG_BLCKSZ
- pageHeaderSize
- SizeOfXLogContRecord
;
3520 if (contrecord
->xl_rem_len
> len
)
3522 memcpy(buffer
, (char *) contrecord
+ SizeOfXLogContRecord
, len
);
3527 memcpy(buffer
, (char *) contrecord
+ SizeOfXLogContRecord
,
3528 contrecord
->xl_rem_len
);
3531 if (!RecordIsValid(record
, *RecPtr
, emode
))
3532 goto next_record_is_invalid
;
3533 pageHeaderSize
= XLogPageHeaderSize((XLogPageHeader
) readBuf
);
3534 if (XLOG_BLCKSZ
- SizeOfXLogRecord
>= pageHeaderSize
+
3535 MAXALIGN(SizeOfXLogContRecord
+ contrecord
->xl_rem_len
))
3537 nextRecord
= (XLogRecord
*) ((char *) contrecord
+
3538 MAXALIGN(SizeOfXLogContRecord
+ contrecord
->xl_rem_len
));
3540 EndRecPtr
.xlogid
= readId
;
3541 EndRecPtr
.xrecoff
= readSeg
* XLogSegSize
+ readOff
+
3543 MAXALIGN(SizeOfXLogContRecord
+ contrecord
->xl_rem_len
);
3544 ReadRecPtr
= *RecPtr
;
3545 /* needn't worry about XLOG SWITCH, it can't cross page boundaries */
3549 /* Record does not cross a page boundary */
3550 if (!RecordIsValid(record
, *RecPtr
, emode
))
3551 goto next_record_is_invalid
;
3552 if (XLOG_BLCKSZ
- SizeOfXLogRecord
>= RecPtr
->xrecoff
% XLOG_BLCKSZ
+
3553 MAXALIGN(total_len
))
3554 nextRecord
= (XLogRecord
*) ((char *) record
+ MAXALIGN(total_len
));
3555 EndRecPtr
.xlogid
= RecPtr
->xlogid
;
3556 EndRecPtr
.xrecoff
= RecPtr
->xrecoff
+ MAXALIGN(total_len
);
3557 ReadRecPtr
= *RecPtr
;
3558 memcpy(buffer
, record
, total_len
);
3561 * Special processing if it's an XLOG SWITCH record
3563 if (record
->xl_rmid
== RM_XLOG_ID
&& record
->xl_info
== XLOG_SWITCH
)
3565 /* Pretend it extends to end of segment */
3566 EndRecPtr
.xrecoff
+= XLogSegSize
- 1;
3567 EndRecPtr
.xrecoff
-= EndRecPtr
.xrecoff
% XLogSegSize
;
3568 nextRecord
= NULL
; /* definitely not on same page */
3571 * Pretend that readBuf contains the last page of the segment. This is
3572 * just to avoid Assert failure in StartupXLOG if XLOG ends with this
3575 readOff
= XLogSegSize
- XLOG_BLCKSZ
;
3577 return (XLogRecord
*) buffer
;
3579 next_record_is_invalid
:;
3590 * Check whether the xlog header of a page just read in looks valid.
3592 * This is just a convenience subroutine to avoid duplicated code in
3593 * ReadRecord. It's not intended for use from anywhere else.
3596 ValidXLOGHeader(XLogPageHeader hdr
, int emode
)
3600 if (hdr
->xlp_magic
!= XLOG_PAGE_MAGIC
)
3603 (errmsg("invalid magic number %04X in log file %u, segment %u, offset %u",
3604 hdr
->xlp_magic
, readId
, readSeg
, readOff
)));
3607 if ((hdr
->xlp_info
& ~XLP_ALL_FLAGS
) != 0)
3610 (errmsg("invalid info bits %04X in log file %u, segment %u, offset %u",
3611 hdr
->xlp_info
, readId
, readSeg
, readOff
)));
3614 if (hdr
->xlp_info
& XLP_LONG_HEADER
)
3616 XLogLongPageHeader longhdr
= (XLogLongPageHeader
) hdr
;
3618 if (longhdr
->xlp_sysid
!= ControlFile
->system_identifier
)
3620 char fhdrident_str
[32];
3621 char sysident_str
[32];
3624 * Format sysids separately to keep platform-dependent format code
3625 * out of the translatable message string.
3627 snprintf(fhdrident_str
, sizeof(fhdrident_str
), UINT64_FORMAT
,
3628 longhdr
->xlp_sysid
);
3629 snprintf(sysident_str
, sizeof(sysident_str
), UINT64_FORMAT
,
3630 ControlFile
->system_identifier
);
3632 (errmsg("WAL file is from different system"),
3633 errdetail("WAL file SYSID is %s, pg_control SYSID is %s",
3634 fhdrident_str
, sysident_str
)));
3637 if (longhdr
->xlp_seg_size
!= XLogSegSize
)
3640 (errmsg("WAL file is from different system"),
3641 errdetail("Incorrect XLOG_SEG_SIZE in page header.")));
3644 if (longhdr
->xlp_xlog_blcksz
!= XLOG_BLCKSZ
)
3647 (errmsg("WAL file is from different system"),
3648 errdetail("Incorrect XLOG_BLCKSZ in page header.")));
3652 else if (readOff
== 0)
3654 /* hmm, first page of file doesn't have a long header? */
3656 (errmsg("invalid info bits %04X in log file %u, segment %u, offset %u",
3657 hdr
->xlp_info
, readId
, readSeg
, readOff
)));
3661 recaddr
.xlogid
= readId
;
3662 recaddr
.xrecoff
= readSeg
* XLogSegSize
+ readOff
;
3663 if (!XLByteEQ(hdr
->xlp_pageaddr
, recaddr
))
3666 (errmsg("unexpected pageaddr %X/%X in log file %u, segment %u, offset %u",
3667 hdr
->xlp_pageaddr
.xlogid
, hdr
->xlp_pageaddr
.xrecoff
,
3668 readId
, readSeg
, readOff
)));
3673 * Check page TLI is one of the expected values.
3675 if (!list_member_int(expectedTLIs
, (int) hdr
->xlp_tli
))
3678 (errmsg("unexpected timeline ID %u in log file %u, segment %u, offset %u",
3680 readId
, readSeg
, readOff
)));
3685 * Since child timelines are always assigned a TLI greater than their
3686 * immediate parent's TLI, we should never see TLI go backwards across
3687 * successive pages of a consistent WAL sequence.
3689 * Of course this check should only be applied when advancing sequentially
3690 * across pages; therefore ReadRecord resets lastPageTLI to zero when
3691 * going to a random page.
3693 if (hdr
->xlp_tli
< lastPageTLI
)
3696 (errmsg("out-of-sequence timeline ID %u (after %u) in log file %u, segment %u, offset %u",
3697 hdr
->xlp_tli
, lastPageTLI
,
3698 readId
, readSeg
, readOff
)));
3701 lastPageTLI
= hdr
->xlp_tli
;
3706 * Try to read a timeline's history file.
3708 * If successful, return the list of component TLIs (the given TLI followed by
3709 * its ancestor TLIs). If we can't find the history file, assume that the
3710 * timeline has no parents, and return a list of just the specified timeline
3714 readTimeLineHistory(TimeLineID targetTLI
)
3717 char path
[MAXPGPATH
];
3718 char histfname
[MAXFNAMELEN
];
3719 char fline
[MAXPGPATH
];
3722 if (InArchiveRecovery
)
3724 TLHistoryFileName(histfname
, targetTLI
);
3725 RestoreArchivedFile(path
, histfname
, "RECOVERYHISTORY", 0);
3728 TLHistoryFilePath(path
, targetTLI
);
3730 fd
= AllocateFile(path
, "r");
3733 if (errno
!= ENOENT
)
3735 (errcode_for_file_access(),
3736 errmsg("could not open file \"%s\": %m", path
)));
3737 /* Not there, so assume no parents */
3738 return list_make1_int((int) targetTLI
);
3746 while (fgets(fline
, sizeof(fline
), fd
) != NULL
)
3748 /* skip leading whitespace and check for # comment */
3753 for (ptr
= fline
; *ptr
; ptr
++)
3755 if (!isspace((unsigned char) *ptr
))
3758 if (*ptr
== '\0' || *ptr
== '#')
3761 /* expect a numeric timeline ID as first field of line */
3762 tli
= (TimeLineID
) strtoul(ptr
, &endptr
, 0);
3765 (errmsg("syntax error in history file: %s", fline
),
3766 errhint("Expected a numeric timeline ID.")));
3769 tli
<= (TimeLineID
) linitial_int(result
))
3771 (errmsg("invalid data in history file: %s", fline
),
3772 errhint("Timeline IDs must be in increasing sequence.")));
3774 /* Build list with newest item first */
3775 result
= lcons_int((int) tli
, result
);
3777 /* we ignore the remainder of each line */
3783 targetTLI
<= (TimeLineID
) linitial_int(result
))
3785 (errmsg("invalid data in history file \"%s\"", path
),
3786 errhint("Timeline IDs must be less than child timeline's ID.")));
3788 result
= lcons_int((int) targetTLI
, result
);
3791 (errmsg_internal("history of timeline %u is %s",
3792 targetTLI
, nodeToString(result
))));
3798 * Probe whether a timeline history file exists for the given timeline ID
3801 existsTimeLineHistory(TimeLineID probeTLI
)
3803 char path
[MAXPGPATH
];
3804 char histfname
[MAXFNAMELEN
];
3807 if (InArchiveRecovery
)
3809 TLHistoryFileName(histfname
, probeTLI
);
3810 RestoreArchivedFile(path
, histfname
, "RECOVERYHISTORY", 0);
3813 TLHistoryFilePath(path
, probeTLI
);
3815 fd
= AllocateFile(path
, "r");
3823 if (errno
!= ENOENT
)
3825 (errcode_for_file_access(),
3826 errmsg("could not open file \"%s\": %m", path
)));
3832 * Find the newest existing timeline, assuming that startTLI exists.
3834 * Note: while this is somewhat heuristic, it does positively guarantee
3835 * that (result + 1) is not a known timeline, and therefore it should
3836 * be safe to assign that ID to a new timeline.
3839 findNewestTimeLine(TimeLineID startTLI
)
3841 TimeLineID newestTLI
;
3842 TimeLineID probeTLI
;
3845 * The algorithm is just to probe for the existence of timeline history
3846 * files. XXX is it useful to allow gaps in the sequence?
3848 newestTLI
= startTLI
;
3850 for (probeTLI
= startTLI
+ 1;; probeTLI
++)
3852 if (existsTimeLineHistory(probeTLI
))
3854 newestTLI
= probeTLI
; /* probeTLI exists */
3858 /* doesn't exist, assume we're done */
3867 * Create a new timeline history file.
3869 * newTLI: ID of the new timeline
3870 * parentTLI: ID of its immediate parent
3871 * endTLI et al: ID of the last used WAL file, for annotation purposes
3873 * Currently this is only used during recovery, and so there are no locking
3874 * considerations. But we should be just as tense as XLogFileInit to avoid
3875 * emplacing a bogus file.
3878 writeTimeLineHistory(TimeLineID newTLI
, TimeLineID parentTLI
,
3879 TimeLineID endTLI
, uint32 endLogId
, uint32 endLogSeg
)
3881 char path
[MAXPGPATH
];
3882 char tmppath
[MAXPGPATH
];
3883 char histfname
[MAXFNAMELEN
];
3884 char xlogfname
[MAXFNAMELEN
];
3885 char buffer
[BLCKSZ
];
3890 Assert(newTLI
> parentTLI
); /* else bad selection of newTLI */
3893 * Write into a temp file name.
3895 snprintf(tmppath
, MAXPGPATH
, XLOGDIR
"/xlogtemp.%d", (int) getpid());
3899 /* do not use get_sync_bit() here --- want to fsync only at end of fill */
3900 fd
= BasicOpenFile(tmppath
, O_RDWR
| O_CREAT
| O_EXCL
,
3904 (errcode_for_file_access(),
3905 errmsg("could not create file \"%s\": %m", tmppath
)));
3908 * If a history file exists for the parent, copy it verbatim
3910 if (InArchiveRecovery
)
3912 TLHistoryFileName(histfname
, parentTLI
);
3913 RestoreArchivedFile(path
, histfname
, "RECOVERYHISTORY", 0);
3916 TLHistoryFilePath(path
, parentTLI
);
3918 srcfd
= BasicOpenFile(path
, O_RDONLY
, 0);
3921 if (errno
!= ENOENT
)
3923 (errcode_for_file_access(),
3924 errmsg("could not open file \"%s\": %m", path
)));
3925 /* Not there, so assume parent has no parents */
3932 nbytes
= (int) read(srcfd
, buffer
, sizeof(buffer
));
3933 if (nbytes
< 0 || errno
!= 0)
3935 (errcode_for_file_access(),
3936 errmsg("could not read file \"%s\": %m", path
)));
3940 if ((int) write(fd
, buffer
, nbytes
) != nbytes
)
3942 int save_errno
= errno
;
3945 * If we fail to make the file, delete it to release disk
3951 * if write didn't set errno, assume problem is no disk space
3953 errno
= save_errno
? save_errno
: ENOSPC
;
3956 (errcode_for_file_access(),
3957 errmsg("could not write to file \"%s\": %m", tmppath
)));
3964 * Append one line with the details of this timeline split.
3966 * If we did have a parent file, insert an extra newline just in case the
3967 * parent file failed to end with one.
3969 XLogFileName(xlogfname
, endTLI
, endLogId
, endLogSeg
);
3971 snprintf(buffer
, sizeof(buffer
),
3972 "%s%u\t%s\t%s transaction %u at %s\n",
3973 (srcfd
< 0) ? "" : "\n",
3976 recoveryStopAfter
? "after" : "before",
3978 timestamptz_to_str(recoveryStopTime
));
3980 nbytes
= strlen(buffer
);
3982 if ((int) write(fd
, buffer
, nbytes
) != nbytes
)
3984 int save_errno
= errno
;
3987 * If we fail to make the file, delete it to release disk space
3990 /* if write didn't set errno, assume problem is no disk space */
3991 errno
= save_errno
? save_errno
: ENOSPC
;
3994 (errcode_for_file_access(),
3995 errmsg("could not write to file \"%s\": %m", tmppath
)));
3998 if (pg_fsync(fd
) != 0)
4000 (errcode_for_file_access(),
4001 errmsg("could not fsync file \"%s\": %m", tmppath
)));
4005 (errcode_for_file_access(),
4006 errmsg("could not close file \"%s\": %m", tmppath
)));
4010 * Now move the completed history file into place with its final name.
4012 TLHistoryFilePath(path
, newTLI
);
4015 * Prefer link() to rename() here just to be really sure that we don't
4016 * overwrite an existing logfile. However, there shouldn't be one, so
4017 * rename() is an acceptable substitute except for the truly paranoid.
4019 #if HAVE_WORKING_LINK
4020 if (link(tmppath
, path
) < 0)
4022 (errcode_for_file_access(),
4023 errmsg("could not link file \"%s\" to \"%s\": %m",
4027 if (rename(tmppath
, path
) < 0)
4029 (errcode_for_file_access(),
4030 errmsg("could not rename file \"%s\" to \"%s\": %m",
4034 /* The history file can be archived immediately. */
4035 TLHistoryFileName(histfname
, newTLI
);
4036 XLogArchiveNotify(histfname
);
4040 * I/O routines for pg_control
4042 * *ControlFile is a buffer in shared memory that holds an image of the
4043 * contents of pg_control. WriteControlFile() initializes pg_control
4044 * given a preloaded buffer, ReadControlFile() loads the buffer from
4045 * the pg_control file (during postmaster or standalone-backend startup),
4046 * and UpdateControlFile() rewrites pg_control after we modify xlog state.
4048 * For simplicity, WriteControlFile() initializes the fields of pg_control
4049 * that are related to checking backend/database compatibility, and
4050 * ReadControlFile() verifies they are correct. We could split out the
4051 * I/O and compatibility-check functions, but there seems no need currently.
4054 WriteControlFile(void)
4057 char buffer
[PG_CONTROL_SIZE
]; /* need not be aligned */
4060 * Initialize version and compatibility-check fields
4062 ControlFile
->pg_control_version
= PG_CONTROL_VERSION
;
4063 ControlFile
->catalog_version_no
= CATALOG_VERSION_NO
;
4065 ControlFile
->maxAlign
= MAXIMUM_ALIGNOF
;
4066 ControlFile
->floatFormat
= FLOATFORMAT_VALUE
;
4068 ControlFile
->blcksz
= BLCKSZ
;
4069 ControlFile
->relseg_size
= RELSEG_SIZE
;
4070 ControlFile
->xlog_blcksz
= XLOG_BLCKSZ
;
4071 ControlFile
->xlog_seg_size
= XLOG_SEG_SIZE
;
4073 ControlFile
->nameDataLen
= NAMEDATALEN
;
4074 ControlFile
->indexMaxKeys
= INDEX_MAX_KEYS
;
4076 ControlFile
->toast_max_chunk_size
= TOAST_MAX_CHUNK_SIZE
;
4078 #ifdef HAVE_INT64_TIMESTAMP
4079 ControlFile
->enableIntTimes
= true;
4081 ControlFile
->enableIntTimes
= false;
4083 ControlFile
->float4ByVal
= FLOAT4PASSBYVAL
;
4084 ControlFile
->float8ByVal
= FLOAT8PASSBYVAL
;
4086 /* Contents are protected with a CRC */
4087 INIT_CRC32(ControlFile
->crc
);
4088 COMP_CRC32(ControlFile
->crc
,
4089 (char *) ControlFile
,
4090 offsetof(ControlFileData
, crc
));
4091 FIN_CRC32(ControlFile
->crc
);
4094 * We write out PG_CONTROL_SIZE bytes into pg_control, zero-padding the
4095 * excess over sizeof(ControlFileData). This reduces the odds of
4096 * premature-EOF errors when reading pg_control. We'll still fail when we
4097 * check the contents of the file, but hopefully with a more specific
4098 * error than "couldn't read pg_control".
4100 if (sizeof(ControlFileData
) > PG_CONTROL_SIZE
)
4101 elog(PANIC
, "sizeof(ControlFileData) is larger than PG_CONTROL_SIZE; fix either one");
4103 memset(buffer
, 0, PG_CONTROL_SIZE
);
4104 memcpy(buffer
, ControlFile
, sizeof(ControlFileData
));
4106 fd
= BasicOpenFile(XLOG_CONTROL_FILE
,
4107 O_RDWR
| O_CREAT
| O_EXCL
| PG_BINARY
,
4111 (errcode_for_file_access(),
4112 errmsg("could not create control file \"%s\": %m",
4113 XLOG_CONTROL_FILE
)));
4116 if (write(fd
, buffer
, PG_CONTROL_SIZE
) != PG_CONTROL_SIZE
)
4118 /* if write didn't set errno, assume problem is no disk space */
4122 (errcode_for_file_access(),
4123 errmsg("could not write to control file: %m")));
4126 if (pg_fsync(fd
) != 0)
4128 (errcode_for_file_access(),
4129 errmsg("could not fsync control file: %m")));
4133 (errcode_for_file_access(),
4134 errmsg("could not close control file: %m")));
4138 ReadControlFile(void)
4146 fd
= BasicOpenFile(XLOG_CONTROL_FILE
,
4151 (errcode_for_file_access(),
4152 errmsg("could not open control file \"%s\": %m",
4153 XLOG_CONTROL_FILE
)));
4155 if (read(fd
, ControlFile
, sizeof(ControlFileData
)) != sizeof(ControlFileData
))
4157 (errcode_for_file_access(),
4158 errmsg("could not read from control file: %m")));
4163 * Check for expected pg_control format version. If this is wrong, the
4164 * CRC check will likely fail because we'll be checking the wrong number
4165 * of bytes. Complaining about wrong version will probably be more
4166 * enlightening than complaining about wrong CRC.
4169 if (ControlFile
->pg_control_version
!= PG_CONTROL_VERSION
&& ControlFile
->pg_control_version
% 65536 == 0 && ControlFile
->pg_control_version
/ 65536 != 0)
4171 (errmsg("database files are incompatible with server"),
4172 errdetail("The database cluster was initialized with PG_CONTROL_VERSION %d (0x%08x),"
4173 " but the server was compiled with PG_CONTROL_VERSION %d (0x%08x).",
4174 ControlFile
->pg_control_version
, ControlFile
->pg_control_version
,
4175 PG_CONTROL_VERSION
, PG_CONTROL_VERSION
),
4176 errhint("This could be a problem of mismatched byte ordering. It looks like you need to initdb.")));
4178 if (ControlFile
->pg_control_version
!= PG_CONTROL_VERSION
)
4180 (errmsg("database files are incompatible with server"),
4181 errdetail("The database cluster was initialized with PG_CONTROL_VERSION %d,"
4182 " but the server was compiled with PG_CONTROL_VERSION %d.",
4183 ControlFile
->pg_control_version
, PG_CONTROL_VERSION
),
4184 errhint("It looks like you need to initdb.")));
4186 /* Now check the CRC. */
4189 (char *) ControlFile
,
4190 offsetof(ControlFileData
, crc
));
4193 if (!EQ_CRC32(crc
, ControlFile
->crc
))
4195 (errmsg("incorrect checksum in control file")));
4198 * Do compatibility checking immediately. If the database isn't
4199 * compatible with the backend executable, we want to abort before we
4200 * can possibly do any damage.
4202 if (ControlFile
->catalog_version_no
!= CATALOG_VERSION_NO
)
4204 (errmsg("database files are incompatible with server"),
4205 errdetail("The database cluster was initialized with CATALOG_VERSION_NO %d,"
4206 " but the server was compiled with CATALOG_VERSION_NO %d.",
4207 ControlFile
->catalog_version_no
, CATALOG_VERSION_NO
),
4208 errhint("It looks like you need to initdb.")));
4209 if (ControlFile
->maxAlign
!= MAXIMUM_ALIGNOF
)
4211 (errmsg("database files are incompatible with server"),
4212 errdetail("The database cluster was initialized with MAXALIGN %d,"
4213 " but the server was compiled with MAXALIGN %d.",
4214 ControlFile
->maxAlign
, MAXIMUM_ALIGNOF
),
4215 errhint("It looks like you need to initdb.")));
4216 if (ControlFile
->floatFormat
!= FLOATFORMAT_VALUE
)
4218 (errmsg("database files are incompatible with server"),
4219 errdetail("The database cluster appears to use a different floating-point number format than the server executable."),
4220 errhint("It looks like you need to initdb.")));
4221 if (ControlFile
->blcksz
!= BLCKSZ
)
4223 (errmsg("database files are incompatible with server"),
4224 errdetail("The database cluster was initialized with BLCKSZ %d,"
4225 " but the server was compiled with BLCKSZ %d.",
4226 ControlFile
->blcksz
, BLCKSZ
),
4227 errhint("It looks like you need to recompile or initdb.")));
4228 if (ControlFile
->relseg_size
!= RELSEG_SIZE
)
4230 (errmsg("database files are incompatible with server"),
4231 errdetail("The database cluster was initialized with RELSEG_SIZE %d,"
4232 " but the server was compiled with RELSEG_SIZE %d.",
4233 ControlFile
->relseg_size
, RELSEG_SIZE
),
4234 errhint("It looks like you need to recompile or initdb.")));
4235 if (ControlFile
->xlog_blcksz
!= XLOG_BLCKSZ
)
4237 (errmsg("database files are incompatible with server"),
4238 errdetail("The database cluster was initialized with XLOG_BLCKSZ %d,"
4239 " but the server was compiled with XLOG_BLCKSZ %d.",
4240 ControlFile
->xlog_blcksz
, XLOG_BLCKSZ
),
4241 errhint("It looks like you need to recompile or initdb.")));
4242 if (ControlFile
->xlog_seg_size
!= XLOG_SEG_SIZE
)
4244 (errmsg("database files are incompatible with server"),
4245 errdetail("The database cluster was initialized with XLOG_SEG_SIZE %d,"
4246 " but the server was compiled with XLOG_SEG_SIZE %d.",
4247 ControlFile
->xlog_seg_size
, XLOG_SEG_SIZE
),
4248 errhint("It looks like you need to recompile or initdb.")));
4249 if (ControlFile
->nameDataLen
!= NAMEDATALEN
)
4251 (errmsg("database files are incompatible with server"),
4252 errdetail("The database cluster was initialized with NAMEDATALEN %d,"
4253 " but the server was compiled with NAMEDATALEN %d.",
4254 ControlFile
->nameDataLen
, NAMEDATALEN
),
4255 errhint("It looks like you need to recompile or initdb.")));
4256 if (ControlFile
->indexMaxKeys
!= INDEX_MAX_KEYS
)
4258 (errmsg("database files are incompatible with server"),
4259 errdetail("The database cluster was initialized with INDEX_MAX_KEYS %d,"
4260 " but the server was compiled with INDEX_MAX_KEYS %d.",
4261 ControlFile
->indexMaxKeys
, INDEX_MAX_KEYS
),
4262 errhint("It looks like you need to recompile or initdb.")));
4263 if (ControlFile
->toast_max_chunk_size
!= TOAST_MAX_CHUNK_SIZE
)
4265 (errmsg("database files are incompatible with server"),
4266 errdetail("The database cluster was initialized with TOAST_MAX_CHUNK_SIZE %d,"
4267 " but the server was compiled with TOAST_MAX_CHUNK_SIZE %d.",
4268 ControlFile
->toast_max_chunk_size
, (int) TOAST_MAX_CHUNK_SIZE
),
4269 errhint("It looks like you need to recompile or initdb.")));
4271 #ifdef HAVE_INT64_TIMESTAMP
4272 if (ControlFile
->enableIntTimes
!= true)
4274 (errmsg("database files are incompatible with server"),
4275 errdetail("The database cluster was initialized without HAVE_INT64_TIMESTAMP"
4276 " but the server was compiled with HAVE_INT64_TIMESTAMP."),
4277 errhint("It looks like you need to recompile or initdb.")));
4279 if (ControlFile
->enableIntTimes
!= false)
4281 (errmsg("database files are incompatible with server"),
4282 errdetail("The database cluster was initialized with HAVE_INT64_TIMESTAMP"
4283 " but the server was compiled without HAVE_INT64_TIMESTAMP."),
4284 errhint("It looks like you need to recompile or initdb.")));
4287 #ifdef USE_FLOAT4_BYVAL
4288 if (ControlFile
->float4ByVal
!= true)
4290 (errmsg("database files are incompatible with server"),
4291 errdetail("The database cluster was initialized without USE_FLOAT4_BYVAL"
4292 " but the server was compiled with USE_FLOAT4_BYVAL."),
4293 errhint("It looks like you need to recompile or initdb.")));
4295 if (ControlFile
->float4ByVal
!= false)
4297 (errmsg("database files are incompatible with server"),
4298 errdetail("The database cluster was initialized with USE_FLOAT4_BYVAL"
4299 " but the server was compiled without USE_FLOAT4_BYVAL."),
4300 errhint("It looks like you need to recompile or initdb.")));
4303 #ifdef USE_FLOAT8_BYVAL
4304 if (ControlFile
->float8ByVal
!= true)
4306 (errmsg("database files are incompatible with server"),
4307 errdetail("The database cluster was initialized without USE_FLOAT8_BYVAL"
4308 " but the server was compiled with USE_FLOAT8_BYVAL."),
4309 errhint("It looks like you need to recompile or initdb.")));
4311 if (ControlFile
->float8ByVal
!= false)
4313 (errmsg("database files are incompatible with server"),
4314 errdetail("The database cluster was initialized with USE_FLOAT8_BYVAL"
4315 " but the server was compiled without USE_FLOAT8_BYVAL."),
4316 errhint("It looks like you need to recompile or initdb.")));
4321 UpdateControlFile(void)
4325 INIT_CRC32(ControlFile
->crc
);
4326 COMP_CRC32(ControlFile
->crc
,
4327 (char *) ControlFile
,
4328 offsetof(ControlFileData
, crc
));
4329 FIN_CRC32(ControlFile
->crc
);
4331 fd
= BasicOpenFile(XLOG_CONTROL_FILE
,
4336 (errcode_for_file_access(),
4337 errmsg("could not open control file \"%s\": %m",
4338 XLOG_CONTROL_FILE
)));
4341 if (write(fd
, ControlFile
, sizeof(ControlFileData
)) != sizeof(ControlFileData
))
4343 /* if write didn't set errno, assume problem is no disk space */
4347 (errcode_for_file_access(),
4348 errmsg("could not write to control file: %m")));
4351 if (pg_fsync(fd
) != 0)
4353 (errcode_for_file_access(),
4354 errmsg("could not fsync control file: %m")));
4358 (errcode_for_file_access(),
4359 errmsg("could not close control file: %m")));
4363 * Initialization of shared memory for XLOG
4371 size
= sizeof(XLogCtlData
);
4372 /* xlblocks array */
4373 size
= add_size(size
, mul_size(sizeof(XLogRecPtr
), XLOGbuffers
));
4374 /* extra alignment padding for XLOG I/O buffers */
4375 size
= add_size(size
, ALIGNOF_XLOG_BUFFER
);
4376 /* and the buffers themselves */
4377 size
= add_size(size
, mul_size(XLOG_BLCKSZ
, XLOGbuffers
));
4380 * Note: we don't count ControlFileData, it comes out of the "slop factor"
4381 * added by CreateSharedMemoryAndSemaphores. This lets us use this
4382 * routine again below to compute the actual allocation size.
4395 ControlFile
= (ControlFileData
*)
4396 ShmemInitStruct("Control File", sizeof(ControlFileData
), &foundCFile
);
4397 XLogCtl
= (XLogCtlData
*)
4398 ShmemInitStruct("XLOG Ctl", XLOGShmemSize(), &foundXLog
);
4400 if (foundCFile
|| foundXLog
)
4402 /* both should be present or neither */
4403 Assert(foundCFile
&& foundXLog
);
4407 memset(XLogCtl
, 0, sizeof(XLogCtlData
));
4410 * Since XLogCtlData contains XLogRecPtr fields, its sizeof should be a
4411 * multiple of the alignment for same, so no extra alignment padding is
4414 allocptr
= ((char *) XLogCtl
) + sizeof(XLogCtlData
);
4415 XLogCtl
->xlblocks
= (XLogRecPtr
*) allocptr
;
4416 memset(XLogCtl
->xlblocks
, 0, sizeof(XLogRecPtr
) * XLOGbuffers
);
4417 allocptr
+= sizeof(XLogRecPtr
) * XLOGbuffers
;
4420 * Align the start of the page buffers to an ALIGNOF_XLOG_BUFFER boundary.
4422 allocptr
= (char *) TYPEALIGN(ALIGNOF_XLOG_BUFFER
, allocptr
);
4423 XLogCtl
->pages
= allocptr
;
4424 memset(XLogCtl
->pages
, 0, (Size
) XLOG_BLCKSZ
* XLOGbuffers
);
4427 * Do basic initialization of XLogCtl shared data. (StartupXLOG will fill
4428 * in additional info.)
4430 XLogCtl
->XLogCacheBlck
= XLOGbuffers
- 1;
4431 XLogCtl
->Insert
.currpage
= (XLogPageHeader
) (XLogCtl
->pages
);
4432 SpinLockInit(&XLogCtl
->info_lck
);
4435 * If we are not in bootstrap mode, pg_control should already exist. Read
4436 * and validate it immediately (see comments in ReadControlFile() for the
4439 if (!IsBootstrapProcessingMode())
4444 * This func must be called ONCE on system install. It creates pg_control
4445 * and the initial XLOG segment.
4450 CheckPoint checkPoint
;
4452 XLogPageHeader page
;
4453 XLogLongPageHeader longpage
;
4456 uint64 sysidentifier
;
4461 * Select a hopefully-unique system identifier code for this installation.
4462 * We use the result of gettimeofday(), including the fractional seconds
4463 * field, as being about as unique as we can easily get. (Think not to
4464 * use random(), since it hasn't been seeded and there's no portable way
4465 * to seed it other than the system clock value...) The upper half of the
4466 * uint64 value is just the tv_sec part, while the lower half is the XOR
4467 * of tv_sec and tv_usec. This is to ensure that we don't lose uniqueness
4468 * unnecessarily if "uint64" is really only 32 bits wide. A person
4469 * knowing this encoding can determine the initialization time of the
4470 * installation, which could perhaps be useful sometimes.
4472 gettimeofday(&tv
, NULL
);
4473 sysidentifier
= ((uint64
) tv
.tv_sec
) << 32;
4474 sysidentifier
|= (uint32
) (tv
.tv_sec
| tv
.tv_usec
);
4476 /* First timeline ID is always 1 */
4479 /* page buffer must be aligned suitably for O_DIRECT */
4480 buffer
= (char *) palloc(XLOG_BLCKSZ
+ ALIGNOF_XLOG_BUFFER
);
4481 page
= (XLogPageHeader
) TYPEALIGN(ALIGNOF_XLOG_BUFFER
, buffer
);
4482 memset(page
, 0, XLOG_BLCKSZ
);
4484 /* Set up information for the initial checkpoint record */
4485 checkPoint
.redo
.xlogid
= 0;
4486 checkPoint
.redo
.xrecoff
= SizeOfXLogLongPHD
;
4487 checkPoint
.ThisTimeLineID
= ThisTimeLineID
;
4488 checkPoint
.nextXidEpoch
= 0;
4489 checkPoint
.nextXid
= FirstNormalTransactionId
;
4490 checkPoint
.nextOid
= FirstBootstrapObjectId
;
4491 checkPoint
.nextMulti
= FirstMultiXactId
;
4492 checkPoint
.nextMultiOffset
= 0;
4493 checkPoint
.time
= (pg_time_t
) time(NULL
);
4495 ShmemVariableCache
->nextXid
= checkPoint
.nextXid
;
4496 ShmemVariableCache
->nextOid
= checkPoint
.nextOid
;
4497 ShmemVariableCache
->oidCount
= 0;
4498 MultiXactSetNextMXact(checkPoint
.nextMulti
, checkPoint
.nextMultiOffset
);
4500 /* Set up the XLOG page header */
4501 page
->xlp_magic
= XLOG_PAGE_MAGIC
;
4502 page
->xlp_info
= XLP_LONG_HEADER
;
4503 page
->xlp_tli
= ThisTimeLineID
;
4504 page
->xlp_pageaddr
.xlogid
= 0;
4505 page
->xlp_pageaddr
.xrecoff
= 0;
4506 longpage
= (XLogLongPageHeader
) page
;
4507 longpage
->xlp_sysid
= sysidentifier
;
4508 longpage
->xlp_seg_size
= XLogSegSize
;
4509 longpage
->xlp_xlog_blcksz
= XLOG_BLCKSZ
;
4511 /* Insert the initial checkpoint record */
4512 record
= (XLogRecord
*) ((char *) page
+ SizeOfXLogLongPHD
);
4513 record
->xl_prev
.xlogid
= 0;
4514 record
->xl_prev
.xrecoff
= 0;
4515 record
->xl_xid
= InvalidTransactionId
;
4516 record
->xl_tot_len
= SizeOfXLogRecord
+ sizeof(checkPoint
);
4517 record
->xl_len
= sizeof(checkPoint
);
4518 record
->xl_info
= XLOG_CHECKPOINT_SHUTDOWN
;
4519 record
->xl_rmid
= RM_XLOG_ID
;
4520 memcpy(XLogRecGetData(record
), &checkPoint
, sizeof(checkPoint
));
4523 COMP_CRC32(crc
, &checkPoint
, sizeof(checkPoint
));
4524 COMP_CRC32(crc
, (char *) record
+ sizeof(pg_crc32
),
4525 SizeOfXLogRecord
- sizeof(pg_crc32
));
4527 record
->xl_crc
= crc
;
4529 /* Create first XLOG segment file */
4530 use_existent
= false;
4531 openLogFile
= XLogFileInit(0, 0, &use_existent
, false);
4533 /* Write the first page with the initial record */
4535 if (write(openLogFile
, page
, XLOG_BLCKSZ
) != XLOG_BLCKSZ
)
4537 /* if write didn't set errno, assume problem is no disk space */
4541 (errcode_for_file_access(),
4542 errmsg("could not write bootstrap transaction log file: %m")));
4545 if (pg_fsync(openLogFile
) != 0)
4547 (errcode_for_file_access(),
4548 errmsg("could not fsync bootstrap transaction log file: %m")));
4550 if (close(openLogFile
))
4552 (errcode_for_file_access(),
4553 errmsg("could not close bootstrap transaction log file: %m")));
4557 /* Now create pg_control */
4559 memset(ControlFile
, 0, sizeof(ControlFileData
));
4560 /* Initialize pg_control status fields */
4561 ControlFile
->system_identifier
= sysidentifier
;
4562 ControlFile
->state
= DB_SHUTDOWNED
;
4563 ControlFile
->time
= checkPoint
.time
;
4564 ControlFile
->checkPoint
= checkPoint
.redo
;
4565 ControlFile
->checkPointCopy
= checkPoint
;
4566 /* some additional ControlFile fields are set in WriteControlFile() */
4570 /* Bootstrap the commit log, too */
4572 BootStrapSUBTRANS();
4573 BootStrapMultiXact();
4579 str_time(pg_time_t tnow
)
4581 static char buf
[128];
4583 pg_strftime(buf
, sizeof(buf
),
4584 "%Y-%m-%d %H:%M:%S %Z",
4585 pg_localtime(&tnow
, log_timezone
));
4591 * See if there is a recovery command file (recovery.conf), and if so
4592 * read in parameters for archive recovery.
4594 * XXX longer term intention is to expand this to
4595 * cater for additional parameters and controls
4596 * possibly use a flex lexer similar to the GUC one
4599 readRecoveryCommandFile(void)
4602 char cmdline
[MAXPGPATH
];
4603 TimeLineID rtli
= 0;
4604 bool rtliGiven
= false;
4605 bool syntaxError
= false;
4607 fd
= AllocateFile(RECOVERY_COMMAND_FILE
, "r");
4610 if (errno
== ENOENT
)
4611 return; /* not there, so no archive recovery */
4613 (errcode_for_file_access(),
4614 errmsg("could not open recovery command file \"%s\": %m",
4615 RECOVERY_COMMAND_FILE
)));
4619 (errmsg("starting archive recovery")));
4624 while (fgets(cmdline
, sizeof(cmdline
), fd
) != NULL
)
4626 /* skip leading whitespace and check for # comment */
4631 for (ptr
= cmdline
; *ptr
; ptr
++)
4633 if (!isspace((unsigned char) *ptr
))
4636 if (*ptr
== '\0' || *ptr
== '#')
4639 /* identify the quoted parameter value */
4640 tok1
= strtok(ptr
, "'");
4646 tok2
= strtok(NULL
, "'");
4652 /* reparse to get just the parameter name */
4653 tok1
= strtok(ptr
, " \t=");
4660 if (strcmp(tok1
, "restore_command") == 0)
4662 recoveryRestoreCommand
= pstrdup(tok2
);
4664 (errmsg("restore_command = '%s'",
4665 recoveryRestoreCommand
)));
4667 else if (strcmp(tok1
, "recovery_target_timeline") == 0)
4670 if (strcmp(tok2
, "latest") == 0)
4675 rtli
= (TimeLineID
) strtoul(tok2
, NULL
, 0);
4676 if (errno
== EINVAL
|| errno
== ERANGE
)
4678 (errmsg("recovery_target_timeline is not a valid number: \"%s\"",
4683 (errmsg("recovery_target_timeline = %u", rtli
)));
4686 (errmsg("recovery_target_timeline = latest")));
4688 else if (strcmp(tok1
, "recovery_target_xid") == 0)
4691 recoveryTargetXid
= (TransactionId
) strtoul(tok2
, NULL
, 0);
4692 if (errno
== EINVAL
|| errno
== ERANGE
)
4694 (errmsg("recovery_target_xid is not a valid number: \"%s\"",
4697 (errmsg("recovery_target_xid = %u",
4698 recoveryTargetXid
)));
4699 recoveryTarget
= true;
4700 recoveryTargetExact
= true;
4702 else if (strcmp(tok1
, "recovery_target_time") == 0)
4705 * if recovery_target_xid specified, then this overrides
4706 * recovery_target_time
4708 if (recoveryTargetExact
)
4710 recoveryTarget
= true;
4711 recoveryTargetExact
= false;
4714 * Convert the time string given by the user to TimestampTz form.
4716 recoveryTargetTime
=
4717 DatumGetTimestampTz(DirectFunctionCall3(timestamptz_in
,
4718 CStringGetDatum(tok2
),
4719 ObjectIdGetDatum(InvalidOid
),
4720 Int32GetDatum(-1)));
4722 (errmsg("recovery_target_time = '%s'",
4723 timestamptz_to_str(recoveryTargetTime
))));
4725 else if (strcmp(tok1
, "recovery_target_inclusive") == 0)
4728 * does nothing if a recovery_target is not also set
4730 if (!parse_bool(tok2
, &recoveryTargetInclusive
))
4732 (errcode(ERRCODE_INVALID_PARAMETER_VALUE
),
4733 errmsg("parameter \"recovery_target_inclusive\" requires a Boolean value")));
4735 (errmsg("recovery_target_inclusive = %s", tok2
)));
4739 (errmsg("unrecognized recovery parameter \"%s\"",
4747 (errmsg("syntax error in recovery command file: %s",
4749 errhint("Lines should have the format parameter = 'value'.")));
4751 /* Check that required parameters were supplied */
4752 if (recoveryRestoreCommand
== NULL
)
4754 (errmsg("recovery command file \"%s\" did not specify restore_command",
4755 RECOVERY_COMMAND_FILE
)));
4757 /* Enable fetching from archive recovery area */
4758 InArchiveRecovery
= true;
4761 * If user specified recovery_target_timeline, validate it or compute the
4762 * "latest" value. We can't do this until after we've gotten the restore
4763 * command and set InArchiveRecovery, because we need to fetch timeline
4764 * history files from the archive.
4770 /* Timeline 1 does not have a history file, all else should */
4771 if (rtli
!= 1 && !existsTimeLineHistory(rtli
))
4773 (errmsg("recovery target timeline %u does not exist",
4775 recoveryTargetTLI
= rtli
;
4779 /* We start the "latest" search from pg_control's timeline */
4780 recoveryTargetTLI
= findNewestTimeLine(recoveryTargetTLI
);
4786 * Exit archive-recovery state
4789 exitArchiveRecovery(TimeLineID endTLI
, uint32 endLogId
, uint32 endLogSeg
)
4791 char recoveryPath
[MAXPGPATH
];
4792 char xlogpath
[MAXPGPATH
];
4795 * We are no longer in archive recovery state.
4797 InArchiveRecovery
= false;
4800 * We should have the ending log segment currently open. Verify, and then
4801 * close it (to avoid problems on Windows with trying to rename or delete
4804 Assert(readFile
>= 0);
4805 Assert(readId
== endLogId
);
4806 Assert(readSeg
== endLogSeg
);
4812 * If the segment was fetched from archival storage, we want to replace
4813 * the existing xlog segment (if any) with the archival version. This is
4814 * because whatever is in XLOGDIR is very possibly older than what we have
4815 * from the archives, since it could have come from restoring a PGDATA
4816 * backup. In any case, the archival version certainly is more
4817 * descriptive of what our current database state is, because that is what
4820 * Note that if we are establishing a new timeline, ThisTimeLineID is
4821 * already set to the new value, and so we will create a new file instead
4822 * of overwriting any existing file. (This is, in fact, always the case
4825 snprintf(recoveryPath
, MAXPGPATH
, XLOGDIR
"/RECOVERYXLOG");
4826 XLogFilePath(xlogpath
, ThisTimeLineID
, endLogId
, endLogSeg
);
4828 if (restoredFromArchive
)
4831 (errmsg_internal("moving last restored xlog to \"%s\"",
4833 unlink(xlogpath
); /* might or might not exist */
4834 if (rename(recoveryPath
, xlogpath
) != 0)
4836 (errcode_for_file_access(),
4837 errmsg("could not rename file \"%s\" to \"%s\": %m",
4838 recoveryPath
, xlogpath
)));
4839 /* XXX might we need to fix permissions on the file? */
4844 * If the latest segment is not archival, but there's still a
4845 * RECOVERYXLOG laying about, get rid of it.
4847 unlink(recoveryPath
); /* ignore any error */
4850 * If we are establishing a new timeline, we have to copy data from
4851 * the last WAL segment of the old timeline to create a starting WAL
4852 * segment for the new timeline.
4854 * Notify the archiver that the last WAL segment of the old timeline
4855 * is ready to copy to archival storage. Otherwise, it is not archived
4858 if (endTLI
!= ThisTimeLineID
)
4860 XLogFileCopy(endLogId
, endLogSeg
,
4861 endTLI
, endLogId
, endLogSeg
);
4863 if (XLogArchivingActive())
4865 XLogFileName(xlogpath
, endTLI
, endLogId
, endLogSeg
);
4866 XLogArchiveNotify(xlogpath
);
4872 * Let's just make real sure there are not .ready or .done flags posted
4873 * for the new segment.
4875 XLogFileName(xlogpath
, ThisTimeLineID
, endLogId
, endLogSeg
);
4876 XLogArchiveCleanup(xlogpath
);
4878 /* Get rid of any remaining recovered timeline-history file, too */
4879 snprintf(recoveryPath
, MAXPGPATH
, XLOGDIR
"/RECOVERYHISTORY");
4880 unlink(recoveryPath
); /* ignore any error */
4883 * Rename the config file out of the way, so that we don't accidentally
4884 * re-enter archive recovery mode in a subsequent crash.
4886 unlink(RECOVERY_COMMAND_DONE
);
4887 if (rename(RECOVERY_COMMAND_FILE
, RECOVERY_COMMAND_DONE
) != 0)
4889 (errcode_for_file_access(),
4890 errmsg("could not rename file \"%s\" to \"%s\": %m",
4891 RECOVERY_COMMAND_FILE
, RECOVERY_COMMAND_DONE
)));
4894 (errmsg("archive recovery complete")));
4898 * For point-in-time recovery, this function decides whether we want to
4899 * stop applying the XLOG at or after the current record.
4901 * Returns TRUE if we are stopping, FALSE otherwise. On TRUE return,
4902 * *includeThis is set TRUE if we should apply this record before stopping.
4904 * We also track the timestamp of the latest applied COMMIT/ABORT record
4905 * in recoveryLastXTime, for logging purposes.
4906 * Also, some information is saved in recoveryStopXid et al for use in
4907 * annotating the new timeline's history file.
4910 recoveryStopsHere(XLogRecord
*record
, bool *includeThis
)
4914 TimestampTz recordXtime
;
4916 /* We only consider stopping at COMMIT or ABORT records */
4917 if (record
->xl_rmid
!= RM_XACT_ID
)
4919 record_info
= record
->xl_info
& ~XLR_INFO_MASK
;
4920 if (record_info
== XLOG_XACT_COMMIT
)
4922 xl_xact_commit
*recordXactCommitData
;
4924 recordXactCommitData
= (xl_xact_commit
*) XLogRecGetData(record
);
4925 recordXtime
= recordXactCommitData
->xact_time
;
4927 else if (record_info
== XLOG_XACT_ABORT
)
4929 xl_xact_abort
*recordXactAbortData
;
4931 recordXactAbortData
= (xl_xact_abort
*) XLogRecGetData(record
);
4932 recordXtime
= recordXactAbortData
->xact_time
;
4937 /* Do we have a PITR target at all? */
4938 if (!recoveryTarget
)
4940 recoveryLastXTime
= recordXtime
;
4944 if (recoveryTargetExact
)
4947 * there can be only one transaction end record with this exact
4950 * when testing for an xid, we MUST test for equality only, since
4951 * transactions are numbered in the order they start, not the order
4952 * they complete. A higher numbered xid will complete before you about
4953 * 50% of the time...
4955 stopsHere
= (record
->xl_xid
== recoveryTargetXid
);
4957 *includeThis
= recoveryTargetInclusive
;
4962 * there can be many transactions that share the same commit time, so
4963 * we stop after the last one, if we are inclusive, or stop at the
4964 * first one if we are exclusive
4966 if (recoveryTargetInclusive
)
4967 stopsHere
= (recordXtime
> recoveryTargetTime
);
4969 stopsHere
= (recordXtime
>= recoveryTargetTime
);
4971 *includeThis
= false;
4976 recoveryStopXid
= record
->xl_xid
;
4977 recoveryStopTime
= recordXtime
;
4978 recoveryStopAfter
= *includeThis
;
4980 if (record_info
== XLOG_XACT_COMMIT
)
4982 if (recoveryStopAfter
)
4984 (errmsg("recovery stopping after commit of transaction %u, time %s",
4986 timestamptz_to_str(recoveryStopTime
))));
4989 (errmsg("recovery stopping before commit of transaction %u, time %s",
4991 timestamptz_to_str(recoveryStopTime
))));
4995 if (recoveryStopAfter
)
4997 (errmsg("recovery stopping after abort of transaction %u, time %s",
4999 timestamptz_to_str(recoveryStopTime
))));
5002 (errmsg("recovery stopping before abort of transaction %u, time %s",
5004 timestamptz_to_str(recoveryStopTime
))));
5007 if (recoveryStopAfter
)
5008 recoveryLastXTime
= recordXtime
;
5011 recoveryLastXTime
= recordXtime
;
5017 * This must be called ONCE during postmaster or standalone-backend startup
5022 XLogCtlInsert
*Insert
;
5023 CheckPoint checkPoint
;
5025 bool reachedStopPoint
= false;
5026 bool haveBackupLabel
= false;
5036 TransactionId oldestActiveXID
;
5038 XLogCtl
->SharedRecoveryInProgress
= true;
5041 * Read control file and check XLOG status looks valid.
5043 * Note: in most control paths, *ControlFile is already valid and we need
5044 * not do ReadControlFile() here, but might as well do it to be sure.
5048 if (ControlFile
->state
< DB_SHUTDOWNED
||
5049 ControlFile
->state
> DB_IN_PRODUCTION
||
5050 !XRecOffIsValid(ControlFile
->checkPoint
.xrecoff
))
5052 (errmsg("control file contains invalid data")));
5054 if (ControlFile
->state
== DB_SHUTDOWNED
)
5056 (errmsg("database system was shut down at %s",
5057 str_time(ControlFile
->time
))));
5058 else if (ControlFile
->state
== DB_SHUTDOWNING
)
5060 (errmsg("database system shutdown was interrupted; last known up at %s",
5061 str_time(ControlFile
->time
))));
5062 else if (ControlFile
->state
== DB_IN_CRASH_RECOVERY
)
5064 (errmsg("database system was interrupted while in recovery at %s",
5065 str_time(ControlFile
->time
)),
5066 errhint("This probably means that some data is corrupted and"
5067 " you will have to use the last backup for recovery.")));
5068 else if (ControlFile
->state
== DB_IN_ARCHIVE_RECOVERY
)
5070 (errmsg("database system was interrupted while in recovery at log time %s",
5071 str_time(ControlFile
->checkPointCopy
.time
)),
5072 errhint("If this has occurred more than once some data might be corrupted"
5073 " and you might need to choose an earlier recovery target.")));
5074 else if (ControlFile
->state
== DB_IN_PRODUCTION
)
5076 (errmsg("database system was interrupted; last known up at %s",
5077 str_time(ControlFile
->time
))));
5079 /* This is just to allow attaching to startup process with a debugger */
5080 #ifdef XLOG_REPLAY_DELAY
5081 if (ControlFile
->state
!= DB_SHUTDOWNED
)
5082 pg_usleep(60000000L);
5086 * Verify that pg_xlog and pg_xlog/archive_status exist. In cases where
5087 * someone has performed a copy for PITR, these directories may have
5088 * been excluded and need to be re-created.
5090 ValidateXLOGDirectoryStructure();
5093 * Initialize on the assumption we want to recover to the same timeline
5094 * that's active according to pg_control.
5096 recoveryTargetTLI
= ControlFile
->checkPointCopy
.ThisTimeLineID
;
5099 * Check for recovery control file, and if so set up state for offline
5102 readRecoveryCommandFile();
5104 /* Now we can determine the list of expected TLIs */
5105 expectedTLIs
= readTimeLineHistory(recoveryTargetTLI
);
5108 * If pg_control's timeline is not in expectedTLIs, then we cannot
5109 * proceed: the backup is not part of the history of the requested
5112 if (!list_member_int(expectedTLIs
,
5113 (int) ControlFile
->checkPointCopy
.ThisTimeLineID
))
5115 (errmsg("requested timeline %u is not a child of database system timeline %u",
5117 ControlFile
->checkPointCopy
.ThisTimeLineID
)));
5119 if (read_backup_label(&checkPointLoc
, &backupStopLoc
))
5122 * When a backup_label file is present, we want to roll forward from
5123 * the checkpoint it identifies, rather than using pg_control.
5125 record
= ReadCheckpointRecord(checkPointLoc
, 0);
5129 (errmsg("checkpoint record is at %X/%X",
5130 checkPointLoc
.xlogid
, checkPointLoc
.xrecoff
)));
5131 InRecovery
= true; /* force recovery even if SHUTDOWNED */
5136 (errmsg("could not locate required checkpoint record"),
5137 errhint("If you are not restoring from a backup, try removing the file \"%s/backup_label\".", DataDir
)));
5139 /* set flag to delete it later */
5140 haveBackupLabel
= true;
5145 * Get the last valid checkpoint record. If the latest one according
5146 * to pg_control is broken, try the next-to-last one.
5148 checkPointLoc
= ControlFile
->checkPoint
;
5149 record
= ReadCheckpointRecord(checkPointLoc
, 1);
5153 (errmsg("checkpoint record is at %X/%X",
5154 checkPointLoc
.xlogid
, checkPointLoc
.xrecoff
)));
5158 checkPointLoc
= ControlFile
->prevCheckPoint
;
5159 record
= ReadCheckpointRecord(checkPointLoc
, 2);
5163 (errmsg("using previous checkpoint record at %X/%X",
5164 checkPointLoc
.xlogid
, checkPointLoc
.xrecoff
)));
5165 InRecovery
= true; /* force recovery even if SHUTDOWNED */
5169 (errmsg("could not locate a valid checkpoint record")));
5173 LastRec
= RecPtr
= checkPointLoc
;
5174 memcpy(&checkPoint
, XLogRecGetData(record
), sizeof(CheckPoint
));
5175 wasShutdown
= (record
->xl_info
== XLOG_CHECKPOINT_SHUTDOWN
);
5178 (errmsg("redo record is at %X/%X; shutdown %s",
5179 checkPoint
.redo
.xlogid
, checkPoint
.redo
.xrecoff
,
5180 wasShutdown
? "TRUE" : "FALSE")));
5182 (errmsg("next transaction ID: %u/%u; next OID: %u",
5183 checkPoint
.nextXidEpoch
, checkPoint
.nextXid
,
5184 checkPoint
.nextOid
)));
5186 (errmsg("next MultiXactId: %u; next MultiXactOffset: %u",
5187 checkPoint
.nextMulti
, checkPoint
.nextMultiOffset
)));
5188 if (!TransactionIdIsNormal(checkPoint
.nextXid
))
5190 (errmsg("invalid next transaction ID")));
5192 ShmemVariableCache
->nextXid
= checkPoint
.nextXid
;
5193 ShmemVariableCache
->nextOid
= checkPoint
.nextOid
;
5194 ShmemVariableCache
->oidCount
= 0;
5195 MultiXactSetNextMXact(checkPoint
.nextMulti
, checkPoint
.nextMultiOffset
);
5198 * We must replay WAL entries using the same TimeLineID they were created
5199 * under, so temporarily adopt the TLI indicated by the checkpoint (see
5200 * also xlog_redo()).
5202 ThisTimeLineID
= checkPoint
.ThisTimeLineID
;
5204 RedoRecPtr
= XLogCtl
->Insert
.RedoRecPtr
= checkPoint
.redo
;
5206 if (XLByteLT(RecPtr
, checkPoint
.redo
))
5208 (errmsg("invalid redo in checkpoint record")));
5211 * Check whether we need to force recovery from WAL. If it appears to
5212 * have been a clean shutdown and we did not have a recovery.conf file,
5213 * then assume no recovery needed.
5215 if (XLByteLT(checkPoint
.redo
, RecPtr
))
5219 (errmsg("invalid redo record in shutdown checkpoint")));
5222 else if (ControlFile
->state
!= DB_SHUTDOWNED
)
5224 else if (InArchiveRecovery
)
5226 /* force recovery due to presence of recovery.conf */
5236 * Update pg_control to show that we are recovering and to show the
5237 * selected checkpoint as the place we are starting from. We also mark
5238 * pg_control with any minimum recovery stop point obtained from a
5239 * backup history file.
5241 if (InArchiveRecovery
)
5244 (errmsg("automatic recovery in progress")));
5245 ControlFile
->state
= DB_IN_ARCHIVE_RECOVERY
;
5250 (errmsg("database system was not properly shut down; "
5251 "automatic recovery in progress")));
5252 ControlFile
->state
= DB_IN_CRASH_RECOVERY
;
5254 ControlFile
->prevCheckPoint
= ControlFile
->checkPoint
;
5255 ControlFile
->checkPoint
= checkPointLoc
;
5256 ControlFile
->checkPointCopy
= checkPoint
;
5257 if (backupStopLoc
.xlogid
!= 0 || backupStopLoc
.xrecoff
!= 0)
5259 if (XLByteLT(ControlFile
->minRecoveryPoint
, backupStopLoc
))
5260 ControlFile
->minRecoveryPoint
= backupStopLoc
;
5262 ControlFile
->time
= (pg_time_t
) time(NULL
);
5263 /* No need to hold ControlFileLock yet, we aren't up far enough */
5264 UpdateControlFile();
5266 /* update our local copy of minRecoveryPoint */
5267 minRecoveryPoint
= ControlFile
->minRecoveryPoint
;
5270 * Reset pgstat data, because it may be invalid after recovery.
5275 * If there was a backup label file, it's done its job and the info
5276 * has now been propagated into pg_control. We must get rid of the
5277 * label file so that if we crash during recovery, we'll pick up at
5278 * the latest recovery restartpoint instead of going all the way back
5279 * to the backup start point. It seems prudent though to just rename
5280 * the file out of the way rather than delete it completely.
5282 if (haveBackupLabel
)
5284 unlink(BACKUP_LABEL_OLD
);
5285 if (rename(BACKUP_LABEL_FILE
, BACKUP_LABEL_OLD
) != 0)
5287 (errcode_for_file_access(),
5288 errmsg("could not rename file \"%s\" to \"%s\": %m",
5289 BACKUP_LABEL_FILE
, BACKUP_LABEL_OLD
)));
5292 /* Initialize resource managers */
5293 for (rmid
= 0; rmid
<= RM_MAX_ID
; rmid
++)
5295 if (RmgrTable
[rmid
].rm_startup
!= NULL
)
5296 RmgrTable
[rmid
].rm_startup();
5300 * Find the first record that logically follows the checkpoint --- it
5301 * might physically precede it, though.
5303 if (XLByteLT(checkPoint
.redo
, RecPtr
))
5305 /* back up to find the record */
5306 record
= ReadRecord(&(checkPoint
.redo
), PANIC
);
5310 /* just have to read next record after CheckPoint */
5311 record
= ReadRecord(NULL
, LOG
);
5316 bool recoveryContinue
= true;
5317 bool recoveryApply
= true;
5318 bool reachedMinRecoveryPoint
= false;
5319 ErrorContextCallback errcontext
;
5320 /* use volatile pointer to prevent code rearrangement */
5321 volatile XLogCtlData
*xlogctl
= XLogCtl
;
5323 /* Update shared replayEndRecPtr */
5324 SpinLockAcquire(&xlogctl
->info_lck
);
5325 xlogctl
->replayEndRecPtr
= ReadRecPtr
;
5326 SpinLockRelease(&xlogctl
->info_lck
);
5330 if (minRecoveryPoint
.xlogid
== 0 && minRecoveryPoint
.xrecoff
== 0)
5332 (errmsg("redo starts at %X/%X",
5333 ReadRecPtr
.xlogid
, ReadRecPtr
.xrecoff
)));
5336 (errmsg("redo starts at %X/%X, consistency will be reached at %X/%X",
5337 ReadRecPtr
.xlogid
, ReadRecPtr
.xrecoff
,
5338 minRecoveryPoint
.xlogid
, minRecoveryPoint
.xrecoff
)));
5341 * Let postmaster know we've started redo now, so that it can
5342 * launch bgwriter to perform restartpoints. We don't bother
5343 * during crash recovery as restartpoints can only be performed
5344 * during archive recovery. And we'd like to keep crash recovery
5345 * simple, to avoid introducing bugs that could you from
5346 * recovering after crash.
5348 * After this point, we can no longer assume that we're the only
5349 * process in addition to postmaster!
5351 if (InArchiveRecovery
&& IsUnderPostmaster
)
5352 SendPostmasterSignal(PMSIGNAL_RECOVERY_STARTED
);
5355 * main redo apply loop
5364 initStringInfo(&buf
);
5365 appendStringInfo(&buf
, "REDO @ %X/%X; LSN %X/%X: ",
5366 ReadRecPtr
.xlogid
, ReadRecPtr
.xrecoff
,
5367 EndRecPtr
.xlogid
, EndRecPtr
.xrecoff
);
5368 xlog_outrec(&buf
, record
);
5369 appendStringInfo(&buf
, " - ");
5370 RmgrTable
[record
->xl_rmid
].rm_desc(&buf
,
5372 XLogRecGetData(record
));
5373 elog(LOG
, "%s", buf
.data
);
5379 * Check if we were requested to re-read config file.
5384 ProcessConfigFile(PGC_SIGHUP
);
5388 * Check if we were requested to exit without finishing
5391 if (shutdown_requested
)
5395 * Have we reached our safe starting point? If so, we can
5396 * tell postmaster that the database is consistent now.
5398 if (!reachedMinRecoveryPoint
&&
5399 XLByteLE(minRecoveryPoint
, EndRecPtr
))
5401 reachedMinRecoveryPoint
= true;
5402 if (InArchiveRecovery
)
5405 (errmsg("consistent recovery state reached")));
5406 if (IsUnderPostmaster
)
5407 SendPostmasterSignal(PMSIGNAL_RECOVERY_CONSISTENT
);
5412 * Have we reached our recovery target?
5414 if (recoveryStopsHere(record
, &recoveryApply
))
5416 reachedStopPoint
= true; /* see below */
5417 recoveryContinue
= false;
5422 /* Setup error traceback support for ereport() */
5423 errcontext
.callback
= rm_redo_error_callback
;
5424 errcontext
.arg
= (void *) record
;
5425 errcontext
.previous
= error_context_stack
;
5426 error_context_stack
= &errcontext
;
5428 /* nextXid must be beyond record's xid */
5429 if (TransactionIdFollowsOrEquals(record
->xl_xid
,
5430 ShmemVariableCache
->nextXid
))
5432 ShmemVariableCache
->nextXid
= record
->xl_xid
;
5433 TransactionIdAdvance(ShmemVariableCache
->nextXid
);
5437 * Update shared replayEndRecPtr before replaying this
5438 * record, so that XLogFlush will update minRecoveryPoint
5441 SpinLockAcquire(&xlogctl
->info_lck
);
5442 xlogctl
->replayEndRecPtr
= EndRecPtr
;
5443 SpinLockRelease(&xlogctl
->info_lck
);
5445 RmgrTable
[record
->xl_rmid
].rm_redo(EndRecPtr
, record
);
5447 /* Pop the error context stack */
5448 error_context_stack
= errcontext
.previous
;
5450 LastRec
= ReadRecPtr
;
5452 record
= ReadRecord(NULL
, LOG
);
5453 } while (record
!= NULL
&& recoveryContinue
);
5456 * end of main redo apply loop
5460 (errmsg("redo done at %X/%X",
5461 ReadRecPtr
.xlogid
, ReadRecPtr
.xrecoff
)));
5462 if (recoveryLastXTime
)
5464 (errmsg("last completed transaction was at log time %s",
5465 timestamptz_to_str(recoveryLastXTime
))));
5470 /* there are no WAL records following the checkpoint */
5472 (errmsg("redo is not required")));
5477 * Re-fetch the last valid or last applied record, so we can identify the
5478 * exact endpoint of what we consider the valid portion of WAL.
5480 record
= ReadRecord(&LastRec
, PANIC
);
5481 EndOfLog
= EndRecPtr
;
5482 XLByteToPrevSeg(EndOfLog
, endLogId
, endLogSeg
);
5485 * Complain if we did not roll forward far enough to render the backup
5488 if (InRecovery
&& XLByteLT(EndOfLog
, minRecoveryPoint
))
5490 if (reachedStopPoint
) /* stopped because of stop request */
5492 (errmsg("requested recovery stop point is before consistent recovery point")));
5493 else /* ran off end of WAL */
5495 (errmsg("WAL ends before consistent recovery point")));
5499 * Consider whether we need to assign a new timeline ID.
5501 * If we are doing an archive recovery, we always assign a new ID. This
5502 * handles a couple of issues. If we stopped short of the end of WAL
5503 * during recovery, then we are clearly generating a new timeline and must
5504 * assign it a unique new ID. Even if we ran to the end, modifying the
5505 * current last segment is problematic because it may result in trying to
5506 * overwrite an already-archived copy of that segment, and we encourage
5507 * DBAs to make their archive_commands reject that. We can dodge the
5508 * problem by making the new active segment have a new timeline ID.
5510 * In a normal crash recovery, we can just extend the timeline we were in.
5512 if (InArchiveRecovery
)
5514 ThisTimeLineID
= findNewestTimeLine(recoveryTargetTLI
) + 1;
5516 (errmsg("selected new timeline ID: %u", ThisTimeLineID
)));
5517 writeTimeLineHistory(ThisTimeLineID
, recoveryTargetTLI
,
5518 curFileTLI
, endLogId
, endLogSeg
);
5521 /* Save the selected TimeLineID in shared memory, too */
5522 XLogCtl
->ThisTimeLineID
= ThisTimeLineID
;
5525 * We are now done reading the old WAL. Turn off archive fetching if it
5526 * was active, and make a writable copy of the last WAL segment. (Note
5527 * that we also have a copy of the last block of the old WAL in readBuf;
5528 * we will use that below.)
5530 if (InArchiveRecovery
)
5531 exitArchiveRecovery(curFileTLI
, endLogId
, endLogSeg
);
5534 * Prepare to write WAL starting at EndOfLog position, and init xlog
5535 * buffer cache using the block containing the last record from the
5536 * previous incarnation.
5538 openLogId
= endLogId
;
5539 openLogSeg
= endLogSeg
;
5540 openLogFile
= XLogFileOpen(openLogId
, openLogSeg
);
5542 Insert
= &XLogCtl
->Insert
;
5543 Insert
->PrevRecord
= LastRec
;
5544 XLogCtl
->xlblocks
[0].xlogid
= openLogId
;
5545 XLogCtl
->xlblocks
[0].xrecoff
=
5546 ((EndOfLog
.xrecoff
- 1) / XLOG_BLCKSZ
+ 1) * XLOG_BLCKSZ
;
5549 * Tricky point here: readBuf contains the *last* block that the LastRec
5550 * record spans, not the one it starts in. The last block is indeed the
5551 * one we want to use.
5553 Assert(readOff
== (XLogCtl
->xlblocks
[0].xrecoff
- XLOG_BLCKSZ
) % XLogSegSize
);
5554 memcpy((char *) Insert
->currpage
, readBuf
, XLOG_BLCKSZ
);
5555 Insert
->currpos
= (char *) Insert
->currpage
+
5556 (EndOfLog
.xrecoff
+ XLOG_BLCKSZ
- XLogCtl
->xlblocks
[0].xrecoff
);
5558 LogwrtResult
.Write
= LogwrtResult
.Flush
= EndOfLog
;
5560 XLogCtl
->Write
.LogwrtResult
= LogwrtResult
;
5561 Insert
->LogwrtResult
= LogwrtResult
;
5562 XLogCtl
->LogwrtResult
= LogwrtResult
;
5564 XLogCtl
->LogwrtRqst
.Write
= EndOfLog
;
5565 XLogCtl
->LogwrtRqst
.Flush
= EndOfLog
;
5567 freespace
= INSERT_FREESPACE(Insert
);
5570 /* Make sure rest of page is zero */
5571 MemSet(Insert
->currpos
, 0, freespace
);
5572 XLogCtl
->Write
.curridx
= 0;
5577 * Whenever Write.LogwrtResult points to exactly the end of a page,
5578 * Write.curridx must point to the *next* page (see XLogWrite()).
5580 * Note: it might seem we should do AdvanceXLInsertBuffer() here, but
5581 * this is sufficient. The first actual attempt to insert a log
5582 * record will advance the insert state.
5584 XLogCtl
->Write
.curridx
= NextBufIdx(0);
5587 /* Pre-scan prepared transactions to find out the range of XIDs present */
5588 oldestActiveXID
= PrescanPreparedTransactions();
5591 * Allow writing WAL for us, so that we can create a checkpoint record.
5592 * But not yet for other backends!
5594 LocalRecoveryInProgress
= false;
5601 * Allow resource managers to do any required cleanup.
5603 for (rmid
= 0; rmid
<= RM_MAX_ID
; rmid
++)
5605 if (RmgrTable
[rmid
].rm_cleanup
!= NULL
)
5606 RmgrTable
[rmid
].rm_cleanup();
5610 * Check to see if the XLOG sequence contained any unresolved
5611 * references to uninitialized pages.
5613 XLogCheckInvalidPages();
5616 * Perform a checkpoint to update all our recovery activity to disk.
5618 * Note that we write a shutdown checkpoint rather than an on-line
5619 * one. This is not particularly critical, but since we may be
5620 * assigning a new TLI, using a shutdown checkpoint allows us to have
5621 * the rule that TLI only changes in shutdown checkpoints, which
5622 * allows some extra error checking in xlog_redo.
5624 CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN
| CHECKPOINT_IMMEDIATE
);
5628 * Preallocate additional log files, if wanted.
5630 PreallocXlogFiles(EndOfLog
);
5633 * Okay, we're officially UP.
5637 LWLockAcquire(ControlFileLock
, LW_EXCLUSIVE
);
5638 ControlFile
->state
= DB_IN_PRODUCTION
;
5639 ControlFile
->time
= (pg_time_t
) time(NULL
);
5640 UpdateControlFile();
5641 LWLockRelease(ControlFileLock
);
5643 /* start the archive_timeout timer running */
5644 XLogCtl
->Write
.lastSegSwitchTime
= (pg_time_t
) time(NULL
);
5646 /* initialize shared-memory copy of latest checkpoint XID/epoch */
5647 XLogCtl
->ckptXidEpoch
= ControlFile
->checkPointCopy
.nextXidEpoch
;
5648 XLogCtl
->ckptXid
= ControlFile
->checkPointCopy
.nextXid
;
5650 /* also initialize latestCompletedXid, to nextXid - 1 */
5651 ShmemVariableCache
->latestCompletedXid
= ShmemVariableCache
->nextXid
;
5652 TransactionIdRetreat(ShmemVariableCache
->latestCompletedXid
);
5654 /* Start up the commit log and related stuff, too */
5656 StartupSUBTRANS(oldestActiveXID
);
5659 /* Reload shared-memory state for prepared transactions */
5660 RecoverPreparedTransactions();
5662 /* Shut down readFile facility, free space */
5675 free(readRecordBuf
);
5676 readRecordBuf
= NULL
;
5677 readRecordBufSize
= 0;
5681 * All done. Allow others to write WAL.
5683 XLogCtl
->SharedRecoveryInProgress
= false;
5687 * Is the system still in recovery?
5689 * As a side-effect, we initialize the local TimeLineID and RedoRecPtr
5690 * variables the first time we see that recovery is finished.
5693 RecoveryInProgress(void)
5696 * We check shared state each time only until we leave recovery mode.
5697 * We can't re-enter recovery, so we rely on the local state variable
5700 if (!LocalRecoveryInProgress
)
5704 /* use volatile pointer to prevent code rearrangement */
5705 volatile XLogCtlData
*xlogctl
= XLogCtl
;
5707 LocalRecoveryInProgress
= xlogctl
->SharedRecoveryInProgress
;
5710 * Initialize TimeLineID and RedoRecPtr the first time we see that
5711 * recovery is finished.
5713 if (!LocalRecoveryInProgress
)
5716 return LocalRecoveryInProgress
;
5721 * Subroutine to try to fetch and validate a prior checkpoint record.
5723 * whichChkpt identifies the checkpoint (merely for reporting purposes).
5724 * 1 for "primary", 2 for "secondary", 0 for "other" (backup_label)
5727 ReadCheckpointRecord(XLogRecPtr RecPtr
, int whichChkpt
)
5731 if (!XRecOffIsValid(RecPtr
.xrecoff
))
5737 (errmsg("invalid primary checkpoint link in control file")));
5741 (errmsg("invalid secondary checkpoint link in control file")));
5745 (errmsg("invalid checkpoint link in backup_label file")));
5751 record
= ReadRecord(&RecPtr
, LOG
);
5759 (errmsg("invalid primary checkpoint record")));
5763 (errmsg("invalid secondary checkpoint record")));
5767 (errmsg("invalid checkpoint record")));
5772 if (record
->xl_rmid
!= RM_XLOG_ID
)
5778 (errmsg("invalid resource manager ID in primary checkpoint record")));
5782 (errmsg("invalid resource manager ID in secondary checkpoint record")));
5786 (errmsg("invalid resource manager ID in checkpoint record")));
5791 if (record
->xl_info
!= XLOG_CHECKPOINT_SHUTDOWN
&&
5792 record
->xl_info
!= XLOG_CHECKPOINT_ONLINE
)
5798 (errmsg("invalid xl_info in primary checkpoint record")));
5802 (errmsg("invalid xl_info in secondary checkpoint record")));
5806 (errmsg("invalid xl_info in checkpoint record")));
5811 if (record
->xl_len
!= sizeof(CheckPoint
) ||
5812 record
->xl_tot_len
!= SizeOfXLogRecord
+ sizeof(CheckPoint
))
5818 (errmsg("invalid length of primary checkpoint record")));
5822 (errmsg("invalid length of secondary checkpoint record")));
5826 (errmsg("invalid length of checkpoint record")));
5835 * This must be called during startup of a backend process, except that
5836 * it need not be called in a standalone backend (which does StartupXLOG
5837 * instead). We need to initialize the local copies of ThisTimeLineID and
5840 * Note: before Postgres 8.0, we went to some effort to keep the postmaster
5841 * process's copies of ThisTimeLineID and RedoRecPtr valid too. This was
5842 * unnecessary however, since the postmaster itself never touches XLOG anyway.
5845 InitXLOGAccess(void)
5847 /* ThisTimeLineID doesn't change so we need no lock to copy it */
5848 ThisTimeLineID
= XLogCtl
->ThisTimeLineID
;
5849 Assert(ThisTimeLineID
!= 0);
5851 /* Use GetRedoRecPtr to copy the RedoRecPtr safely */
5852 (void) GetRedoRecPtr();
5856 * Once spawned, a backend may update its local RedoRecPtr from
5857 * XLogCtl->Insert.RedoRecPtr; it must hold the insert lock or info_lck
5858 * to do so. This is done in XLogInsert() or GetRedoRecPtr().
5863 /* use volatile pointer to prevent code rearrangement */
5864 volatile XLogCtlData
*xlogctl
= XLogCtl
;
5866 SpinLockAcquire(&xlogctl
->info_lck
);
5867 Assert(XLByteLE(RedoRecPtr
, xlogctl
->Insert
.RedoRecPtr
));
5868 RedoRecPtr
= xlogctl
->Insert
.RedoRecPtr
;
5869 SpinLockRelease(&xlogctl
->info_lck
);
5875 * GetInsertRecPtr -- Returns the current insert position.
5877 * NOTE: The value *actually* returned is the position of the last full
5878 * xlog page. It lags behind the real insert position by at most 1 page.
5879 * For that, we don't need to acquire WALInsertLock which can be quite
5880 * heavily contended, and an approximation is enough for the current
5881 * usage of this function.
5884 GetInsertRecPtr(void)
5886 /* use volatile pointer to prevent code rearrangement */
5887 volatile XLogCtlData
*xlogctl
= XLogCtl
;
5890 SpinLockAcquire(&xlogctl
->info_lck
);
5891 recptr
= xlogctl
->LogwrtRqst
.Write
;
5892 SpinLockRelease(&xlogctl
->info_lck
);
5898 * Get the time of the last xlog segment switch
5901 GetLastSegSwitchTime(void)
5905 /* Need WALWriteLock, but shared lock is sufficient */
5906 LWLockAcquire(WALWriteLock
, LW_SHARED
);
5907 result
= XLogCtl
->Write
.lastSegSwitchTime
;
5908 LWLockRelease(WALWriteLock
);
5914 * GetNextXidAndEpoch - get the current nextXid value and associated epoch
5916 * This is exported for use by code that would like to have 64-bit XIDs.
5917 * We don't really support such things, but all XIDs within the system
5918 * can be presumed "close to" the result, and thus the epoch associated
5919 * with them can be determined.
5922 GetNextXidAndEpoch(TransactionId
*xid
, uint32
*epoch
)
5924 uint32 ckptXidEpoch
;
5925 TransactionId ckptXid
;
5926 TransactionId nextXid
;
5928 /* Must read checkpoint info first, else have race condition */
5930 /* use volatile pointer to prevent code rearrangement */
5931 volatile XLogCtlData
*xlogctl
= XLogCtl
;
5933 SpinLockAcquire(&xlogctl
->info_lck
);
5934 ckptXidEpoch
= xlogctl
->ckptXidEpoch
;
5935 ckptXid
= xlogctl
->ckptXid
;
5936 SpinLockRelease(&xlogctl
->info_lck
);
5939 /* Now fetch current nextXid */
5940 nextXid
= ReadNewTransactionId();
5943 * nextXid is certainly logically later than ckptXid. So if it's
5944 * numerically less, it must have wrapped into the next epoch.
5946 if (nextXid
< ckptXid
)
5950 *epoch
= ckptXidEpoch
;
5954 * This must be called ONCE during postmaster or standalone-backend shutdown
5957 ShutdownXLOG(int code
, Datum arg
)
5960 (errmsg("shutting down")));
5962 if (RecoveryInProgress())
5963 CreateRestartPoint(CHECKPOINT_IS_SHUTDOWN
| CHECKPOINT_IMMEDIATE
);
5965 CreateCheckPoint(CHECKPOINT_IS_SHUTDOWN
| CHECKPOINT_IMMEDIATE
);
5968 ShutdownMultiXact();
5971 (errmsg("database system is shut down")));
5975 * Log start of a checkpoint.
5978 LogCheckpointStart(int flags
, bool restartpoint
)
5983 * XXX: This is hopelessly untranslatable. We could call gettext_noop
5984 * for the main message, but what about all the flags?
5987 msg
= "restartpoint starting:%s%s%s%s%s%s";
5989 msg
= "checkpoint starting:%s%s%s%s%s%s";
5992 (flags
& CHECKPOINT_IS_SHUTDOWN
) ? " shutdown" : "",
5993 (flags
& CHECKPOINT_IMMEDIATE
) ? " immediate" : "",
5994 (flags
& CHECKPOINT_FORCE
) ? " force" : "",
5995 (flags
& CHECKPOINT_WAIT
) ? " wait" : "",
5996 (flags
& CHECKPOINT_CAUSE_XLOG
) ? " xlog" : "",
5997 (flags
& CHECKPOINT_CAUSE_TIME
) ? " time" : "");
6001 * Log end of a checkpoint.
6004 LogCheckpointEnd(bool restartpoint
)
6013 CheckpointStats
.ckpt_end_t
= GetCurrentTimestamp();
6015 TimestampDifference(CheckpointStats
.ckpt_start_t
,
6016 CheckpointStats
.ckpt_end_t
,
6017 &total_secs
, &total_usecs
);
6019 TimestampDifference(CheckpointStats
.ckpt_write_t
,
6020 CheckpointStats
.ckpt_sync_t
,
6021 &write_secs
, &write_usecs
);
6023 TimestampDifference(CheckpointStats
.ckpt_sync_t
,
6024 CheckpointStats
.ckpt_sync_end_t
,
6025 &sync_secs
, &sync_usecs
);
6028 elog(LOG
, "restartpoint complete: wrote %d buffers (%.1f%%); "
6029 "write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s",
6030 CheckpointStats
.ckpt_bufs_written
,
6031 (double) CheckpointStats
.ckpt_bufs_written
* 100 / NBuffers
,
6032 write_secs
, write_usecs
/ 1000,
6033 sync_secs
, sync_usecs
/ 1000,
6034 total_secs
, total_usecs
/ 1000);
6036 elog(LOG
, "checkpoint complete: wrote %d buffers (%.1f%%); "
6037 "%d transaction log file(s) added, %d removed, %d recycled; "
6038 "write=%ld.%03d s, sync=%ld.%03d s, total=%ld.%03d s",
6039 CheckpointStats
.ckpt_bufs_written
,
6040 (double) CheckpointStats
.ckpt_bufs_written
* 100 / NBuffers
,
6041 CheckpointStats
.ckpt_segs_added
,
6042 CheckpointStats
.ckpt_segs_removed
,
6043 CheckpointStats
.ckpt_segs_recycled
,
6044 write_secs
, write_usecs
/ 1000,
6045 sync_secs
, sync_usecs
/ 1000,
6046 total_secs
, total_usecs
/ 1000);
6050 * Perform a checkpoint --- either during shutdown, or on-the-fly
6052 * flags is a bitwise OR of the following:
6053 * CHECKPOINT_IS_SHUTDOWN: checkpoint is for database shutdown.
6054 * CHECKPOINT_IMMEDIATE: finish the checkpoint ASAP,
6055 * ignoring checkpoint_completion_target parameter.
6056 * CHECKPOINT_FORCE: force a checkpoint even if no XLOG activity has occured
6057 * since the last one (implied by CHECKPOINT_IS_SHUTDOWN).
6059 * Note: flags contains other bits, of interest here only for logging purposes.
6060 * In particular note that this routine is synchronous and does not pay
6061 * attention to CHECKPOINT_WAIT.
6064 CreateCheckPoint(int flags
)
6066 bool shutdown
= (flags
& CHECKPOINT_IS_SHUTDOWN
) != 0;
6067 CheckPoint checkPoint
;
6069 XLogCtlInsert
*Insert
= &XLogCtl
->Insert
;
6074 TransactionId
*inCommitXids
;
6077 /* shouldn't happen */
6078 if (RecoveryInProgress())
6079 elog(ERROR
, "can't create a checkpoint during recovery");
6082 * Acquire CheckpointLock to ensure only one checkpoint happens at a time.
6083 * During normal operation, bgwriter is the only process that creates
6084 * checkpoints, but at the end of archive recovery, the bgwriter can be
6085 * busy creating a restartpoint while the startup process tries to perform
6086 * the startup checkpoint.
6088 if (!LWLockConditionalAcquire(CheckpointLock
, LW_EXCLUSIVE
))
6093 * A restartpoint is in progress. Wait until it finishes. This can
6094 * cause an extra restartpoint to be performed, but that's OK because
6095 * we're just about to perform a checkpoint anyway. Flushing the
6096 * buffers in this restartpoint can take some time, but that time is
6097 * saved from the upcoming checkpoint so the net effect is zero.
6099 ereport(DEBUG2
, (errmsg("hurrying in-progress restartpoint")));
6100 RequestCheckpoint(CHECKPOINT_IMMEDIATE
| CHECKPOINT_WAIT
);
6102 LWLockAcquire(CheckpointLock
, LW_EXCLUSIVE
);
6106 * Prepare to accumulate statistics.
6108 * Note: because it is possible for log_checkpoints to change while a
6109 * checkpoint proceeds, we always accumulate stats, even if
6110 * log_checkpoints is currently off.
6112 MemSet(&CheckpointStats
, 0, sizeof(CheckpointStats
));
6113 CheckpointStats
.ckpt_start_t
= GetCurrentTimestamp();
6116 * Use a critical section to force system panic if we have trouble.
6118 START_CRIT_SECTION();
6122 LWLockAcquire(ControlFileLock
, LW_EXCLUSIVE
);
6123 ControlFile
->state
= DB_SHUTDOWNING
;
6124 ControlFile
->time
= (pg_time_t
) time(NULL
);
6125 UpdateControlFile();
6126 LWLockRelease(ControlFileLock
);
6130 * Let smgr prepare for checkpoint; this has to happen before we determine
6131 * the REDO pointer. Note that smgr must not do anything that'd have to
6132 * be undone if we decide no checkpoint is needed.
6136 /* Begin filling in the checkpoint WAL record */
6137 MemSet(&checkPoint
, 0, sizeof(checkPoint
));
6138 checkPoint
.ThisTimeLineID
= ThisTimeLineID
;
6139 checkPoint
.time
= (pg_time_t
) time(NULL
);
6142 * We must hold WALInsertLock while examining insert state to determine
6143 * the checkpoint REDO pointer.
6145 LWLockAcquire(WALInsertLock
, LW_EXCLUSIVE
);
6148 * If this isn't a shutdown or forced checkpoint, and we have not inserted
6149 * any XLOG records since the start of the last checkpoint, skip the
6150 * checkpoint. The idea here is to avoid inserting duplicate checkpoints
6151 * when the system is idle. That wastes log space, and more importantly it
6152 * exposes us to possible loss of both current and previous checkpoint
6153 * records if the machine crashes just as we're writing the update.
6154 * (Perhaps it'd make even more sense to checkpoint only when the previous
6155 * checkpoint record is in a different xlog page?)
6157 * We have to make two tests to determine that nothing has happened since
6158 * the start of the last checkpoint: current insertion point must match
6159 * the end of the last checkpoint record, and its redo pointer must point
6162 if ((flags
& (CHECKPOINT_IS_SHUTDOWN
| CHECKPOINT_FORCE
)) == 0)
6164 XLogRecPtr curInsert
;
6166 INSERT_RECPTR(curInsert
, Insert
, Insert
->curridx
);
6167 if (curInsert
.xlogid
== ControlFile
->checkPoint
.xlogid
&&
6168 curInsert
.xrecoff
== ControlFile
->checkPoint
.xrecoff
+
6169 MAXALIGN(SizeOfXLogRecord
+ sizeof(CheckPoint
)) &&
6170 ControlFile
->checkPoint
.xlogid
==
6171 ControlFile
->checkPointCopy
.redo
.xlogid
&&
6172 ControlFile
->checkPoint
.xrecoff
==
6173 ControlFile
->checkPointCopy
.redo
.xrecoff
)
6175 LWLockRelease(WALInsertLock
);
6176 LWLockRelease(CheckpointLock
);
6183 * Compute new REDO record ptr = location of next XLOG record.
6185 * NB: this is NOT necessarily where the checkpoint record itself will be,
6186 * since other backends may insert more XLOG records while we're off doing
6187 * the buffer flush work. Those XLOG records are logically after the
6188 * checkpoint, even though physically before it. Got that?
6190 freespace
= INSERT_FREESPACE(Insert
);
6191 if (freespace
< SizeOfXLogRecord
)
6193 (void) AdvanceXLInsertBuffer(false);
6194 /* OK to ignore update return flag, since we will do flush anyway */
6195 freespace
= INSERT_FREESPACE(Insert
);
6197 INSERT_RECPTR(checkPoint
.redo
, Insert
, Insert
->curridx
);
6200 * Here we update the shared RedoRecPtr for future XLogInsert calls; this
6201 * must be done while holding the insert lock AND the info_lck.
6203 * Note: if we fail to complete the checkpoint, RedoRecPtr will be left
6204 * pointing past where it really needs to point. This is okay; the only
6205 * consequence is that XLogInsert might back up whole buffers that it
6206 * didn't really need to. We can't postpone advancing RedoRecPtr because
6207 * XLogInserts that happen while we are dumping buffers must assume that
6208 * their buffer changes are not included in the checkpoint.
6211 /* use volatile pointer to prevent code rearrangement */
6212 volatile XLogCtlData
*xlogctl
= XLogCtl
;
6214 SpinLockAcquire(&xlogctl
->info_lck
);
6215 RedoRecPtr
= xlogctl
->Insert
.RedoRecPtr
= checkPoint
.redo
;
6216 SpinLockRelease(&xlogctl
->info_lck
);
6220 * Now we can release WAL insert lock, allowing other xacts to proceed
6221 * while we are flushing disk buffers.
6223 LWLockRelease(WALInsertLock
);
6226 * If enabled, log checkpoint start. We postpone this until now so as not
6227 * to log anything if we decided to skip the checkpoint.
6229 if (log_checkpoints
)
6230 LogCheckpointStart(flags
, false);
6232 TRACE_POSTGRESQL_CHECKPOINT_START(flags
);
6235 * Before flushing data, we must wait for any transactions that are
6236 * currently in their commit critical sections. If an xact inserted its
6237 * commit record into XLOG just before the REDO point, then a crash
6238 * restart from the REDO point would not replay that record, which means
6239 * that our flushing had better include the xact's update of pg_clog. So
6240 * we wait till he's out of his commit critical section before proceeding.
6241 * See notes in RecordTransactionCommit().
6243 * Because we've already released WALInsertLock, this test is a bit fuzzy:
6244 * it is possible that we will wait for xacts we didn't really need to
6245 * wait for. But the delay should be short and it seems better to make
6246 * checkpoint take a bit longer than to hold locks longer than necessary.
6247 * (In fact, the whole reason we have this issue is that xact.c does
6248 * commit record XLOG insertion and clog update as two separate steps
6249 * protected by different locks, but again that seems best on grounds of
6250 * minimizing lock contention.)
6252 * A transaction that has not yet set inCommit when we look cannot be at
6253 * risk, since he's not inserted his commit record yet; and one that's
6254 * already cleared it is not at risk either, since he's done fixing clog
6255 * and we will correctly flush the update below. So we cannot miss any
6256 * xacts we need to wait for.
6258 nInCommit
= GetTransactionsInCommit(&inCommitXids
);
6263 pg_usleep(10000L); /* wait for 10 msec */
6264 } while (HaveTransactionsInCommit(inCommitXids
, nInCommit
));
6266 pfree(inCommitXids
);
6269 * Get the other info we need for the checkpoint record.
6271 LWLockAcquire(XidGenLock
, LW_SHARED
);
6272 checkPoint
.nextXid
= ShmemVariableCache
->nextXid
;
6273 LWLockRelease(XidGenLock
);
6275 /* Increase XID epoch if we've wrapped around since last checkpoint */
6276 checkPoint
.nextXidEpoch
= ControlFile
->checkPointCopy
.nextXidEpoch
;
6277 if (checkPoint
.nextXid
< ControlFile
->checkPointCopy
.nextXid
)
6278 checkPoint
.nextXidEpoch
++;
6280 LWLockAcquire(OidGenLock
, LW_SHARED
);
6281 checkPoint
.nextOid
= ShmemVariableCache
->nextOid
;
6283 checkPoint
.nextOid
+= ShmemVariableCache
->oidCount
;
6284 LWLockRelease(OidGenLock
);
6286 MultiXactGetCheckptMulti(shutdown
,
6287 &checkPoint
.nextMulti
,
6288 &checkPoint
.nextMultiOffset
);
6291 * Having constructed the checkpoint record, ensure all shmem disk buffers
6292 * and commit-log buffers are flushed to disk.
6294 * This I/O could fail for various reasons. If so, we will fail to
6295 * complete the checkpoint, but there is no reason to force a system
6296 * panic. Accordingly, exit critical section while doing it.
6300 CheckPointGuts(checkPoint
.redo
, flags
);
6302 START_CRIT_SECTION();
6305 * Now insert the checkpoint record into XLOG.
6307 rdata
.data
= (char *) (&checkPoint
);
6308 rdata
.len
= sizeof(checkPoint
);
6309 rdata
.buffer
= InvalidBuffer
;
6312 recptr
= XLogInsert(RM_XLOG_ID
,
6313 shutdown
? XLOG_CHECKPOINT_SHUTDOWN
:
6314 XLOG_CHECKPOINT_ONLINE
,
6320 * We now have ProcLastRecPtr = start of actual checkpoint record, recptr
6321 * = end of actual checkpoint record.
6323 if (shutdown
&& !XLByteEQ(checkPoint
.redo
, ProcLastRecPtr
))
6325 (errmsg("concurrent transaction log activity while database system is shutting down")));
6328 * Select point at which we can truncate the log, which we base on the
6329 * prior checkpoint's earliest info.
6331 XLByteToSeg(ControlFile
->checkPointCopy
.redo
, _logId
, _logSeg
);
6334 * Update the control file.
6336 LWLockAcquire(ControlFileLock
, LW_EXCLUSIVE
);
6338 ControlFile
->state
= DB_SHUTDOWNED
;
6339 ControlFile
->prevCheckPoint
= ControlFile
->checkPoint
;
6340 ControlFile
->checkPoint
= ProcLastRecPtr
;
6341 ControlFile
->checkPointCopy
= checkPoint
;
6342 ControlFile
->time
= (pg_time_t
) time(NULL
);
6343 UpdateControlFile();
6344 LWLockRelease(ControlFileLock
);
6346 /* Update shared-memory copy of checkpoint XID/epoch */
6348 /* use volatile pointer to prevent code rearrangement */
6349 volatile XLogCtlData
*xlogctl
= XLogCtl
;
6351 SpinLockAcquire(&xlogctl
->info_lck
);
6352 xlogctl
->ckptXidEpoch
= checkPoint
.nextXidEpoch
;
6353 xlogctl
->ckptXid
= checkPoint
.nextXid
;
6354 SpinLockRelease(&xlogctl
->info_lck
);
6358 * We are now done with critical updates; no need for system panic if we
6359 * have trouble while fooling with old log segments.
6364 * Let smgr do post-checkpoint cleanup (eg, deleting old files).
6369 * Delete old log files (those no longer needed even for previous
6372 if (_logId
|| _logSeg
)
6374 PrevLogSeg(_logId
, _logSeg
);
6375 RemoveOldXlogFiles(_logId
, _logSeg
, recptr
);
6379 * Make more log segments if needed. (Do this after recycling old log
6380 * segments, since that may supply some of the needed files.)
6383 PreallocXlogFiles(recptr
);
6386 * Truncate pg_subtrans if possible. We can throw away all data before
6387 * the oldest XMIN of any running transaction. No future transaction will
6388 * attempt to reference any pg_subtrans entry older than that (see Asserts
6389 * in subtrans.c). During recovery, though, we mustn't do this because
6390 * StartupSUBTRANS hasn't been called yet.
6393 TruncateSUBTRANS(GetOldestXmin(true, false));
6395 /* All real work is done, but log before releasing lock. */
6396 if (log_checkpoints
)
6397 LogCheckpointEnd(false);
6399 TRACE_POSTGRESQL_CHECKPOINT_DONE(CheckpointStats
.ckpt_bufs_written
,
6401 CheckpointStats
.ckpt_segs_added
,
6402 CheckpointStats
.ckpt_segs_removed
,
6403 CheckpointStats
.ckpt_segs_recycled
);
6405 LWLockRelease(CheckpointLock
);
6409 * Flush all data in shared memory to disk, and fsync
6411 * This is the common code shared between regular checkpoints and
6412 * recovery restartpoints.
6415 CheckPointGuts(XLogRecPtr checkPointRedo
, int flags
)
6418 CheckPointSUBTRANS();
6419 CheckPointMultiXact();
6420 CheckPointBuffers(flags
); /* performs all required fsyncs */
6421 /* We deliberately delay 2PC checkpointing as long as possible */
6422 CheckPointTwoPhase(checkPointRedo
);
6426 * This is used during WAL recovery to establish a point from which recovery
6427 * can roll forward without replaying the entire recovery log. This function
6428 * is called each time a checkpoint record is read from XLOG. It is stored
6429 * in shared memory, so that it can be used as a restartpoint later on.
6432 RecoveryRestartPoint(const CheckPoint
*checkPoint
)
6435 /* use volatile pointer to prevent code rearrangement */
6436 volatile XLogCtlData
*xlogctl
= XLogCtl
;
6439 * Is it safe to checkpoint? We must ask each of the resource managers
6440 * whether they have any partial state information that might prevent a
6441 * correct restart from this point. If so, we skip this opportunity, but
6442 * return at the next checkpoint record for another try.
6444 for (rmid
= 0; rmid
<= RM_MAX_ID
; rmid
++)
6446 if (RmgrTable
[rmid
].rm_safe_restartpoint
!= NULL
)
6447 if (!(RmgrTable
[rmid
].rm_safe_restartpoint()))
6449 elog(DEBUG2
, "RM %d not safe to record restart point at %X/%X",
6451 checkPoint
->redo
.xlogid
,
6452 checkPoint
->redo
.xrecoff
);
6458 * Copy the checkpoint record to shared memory, so that bgwriter can
6459 * use it the next time it wants to perform a restartpoint.
6461 SpinLockAcquire(&xlogctl
->info_lck
);
6462 XLogCtl
->lastCheckPointRecPtr
= ReadRecPtr
;
6463 memcpy(&XLogCtl
->lastCheckPoint
, checkPoint
, sizeof(CheckPoint
));
6464 SpinLockRelease(&xlogctl
->info_lck
);
6468 * This is similar to CreateCheckPoint, but is used during WAL recovery
6469 * to establish a point from which recovery can roll forward without
6470 * replaying the entire recovery log.
6472 * Returns true if a new restartpoint was established. We can only establish
6473 * a restartpoint if we have replayed a checkpoint record since last
6477 CreateRestartPoint(int flags
)
6479 XLogRecPtr lastCheckPointRecPtr
;
6480 CheckPoint lastCheckPoint
;
6481 /* use volatile pointer to prevent code rearrangement */
6482 volatile XLogCtlData
*xlogctl
= XLogCtl
;
6485 * Acquire CheckpointLock to ensure only one restartpoint or checkpoint
6486 * happens at a time.
6488 LWLockAcquire(CheckpointLock
, LW_EXCLUSIVE
);
6490 /* Get the a local copy of the last checkpoint record. */
6491 SpinLockAcquire(&xlogctl
->info_lck
);
6492 lastCheckPointRecPtr
= xlogctl
->lastCheckPointRecPtr
;
6493 memcpy(&lastCheckPoint
, &XLogCtl
->lastCheckPoint
, sizeof(CheckPoint
));
6494 SpinLockRelease(&xlogctl
->info_lck
);
6497 * Check that we're still in recovery mode. It's ok if we exit recovery
6498 * mode after this check, the restart point is valid anyway.
6500 if (!RecoveryInProgress())
6503 (errmsg("skipping restartpoint, recovery has already ended")));
6504 LWLockRelease(CheckpointLock
);
6509 * If the last checkpoint record we've replayed is already our last
6510 * restartpoint, we can't perform a new restart point. We still update
6511 * minRecoveryPoint in that case, so that if this is a shutdown restart
6512 * point, we won't start up earlier than before. That's not strictly
6513 * necessary, but when we get hot standby capability, it would be rather
6514 * weird if the database opened up for read-only connections at a
6515 * point-in-time before the last shutdown. Such time travel is still
6516 * possible in case of immediate shutdown, though.
6518 * We don't explicitly advance minRecoveryPoint when we do create a
6519 * restartpoint. It's assumed that flushing the buffers will do that
6522 if (XLogRecPtrIsInvalid(lastCheckPointRecPtr
) ||
6523 XLByteLE(lastCheckPoint
.redo
, ControlFile
->checkPointCopy
.redo
))
6525 XLogRecPtr InvalidXLogRecPtr
= {0, 0};
6527 (errmsg("skipping restartpoint, already performed at %X/%X",
6528 lastCheckPoint
.redo
.xlogid
, lastCheckPoint
.redo
.xrecoff
)));
6530 UpdateMinRecoveryPoint(InvalidXLogRecPtr
, true);
6531 LWLockRelease(CheckpointLock
);
6535 if (log_checkpoints
)
6538 * Prepare to accumulate statistics.
6540 MemSet(&CheckpointStats
, 0, sizeof(CheckpointStats
));
6541 CheckpointStats
.ckpt_start_t
= GetCurrentTimestamp();
6543 LogCheckpointStart(flags
, true);
6546 CheckPointGuts(lastCheckPoint
.redo
, flags
);
6549 * Update pg_control, using current time
6551 LWLockAcquire(ControlFileLock
, LW_EXCLUSIVE
);
6552 ControlFile
->prevCheckPoint
= ControlFile
->checkPoint
;
6553 ControlFile
->checkPoint
= lastCheckPointRecPtr
;
6554 ControlFile
->checkPointCopy
= lastCheckPoint
;
6555 ControlFile
->time
= (pg_time_t
) time(NULL
);
6556 UpdateControlFile();
6557 LWLockRelease(ControlFileLock
);
6560 * Currently, there is no need to truncate pg_subtrans during recovery.
6561 * If we did do that, we will need to have called StartupSUBTRANS()
6562 * already and then TruncateSUBTRANS() would go here.
6565 /* All real work is done, but log before releasing lock. */
6566 if (log_checkpoints
)
6567 LogCheckpointEnd(true);
6569 ereport((log_checkpoints
? LOG
: DEBUG2
),
6570 (errmsg("recovery restart point at %X/%X",
6571 lastCheckPoint
.redo
.xlogid
, lastCheckPoint
.redo
.xrecoff
)));
6573 if (recoveryLastXTime
)
6574 ereport((log_checkpoints
? LOG
: DEBUG2
),
6575 (errmsg("last completed transaction was at log time %s",
6576 timestamptz_to_str(recoveryLastXTime
))));
6578 LWLockRelease(CheckpointLock
);
6583 * Write a NEXTOID log record
6586 XLogPutNextOid(Oid nextOid
)
6590 rdata
.data
= (char *) (&nextOid
);
6591 rdata
.len
= sizeof(Oid
);
6592 rdata
.buffer
= InvalidBuffer
;
6594 (void) XLogInsert(RM_XLOG_ID
, XLOG_NEXTOID
, &rdata
);
6597 * We need not flush the NEXTOID record immediately, because any of the
6598 * just-allocated OIDs could only reach disk as part of a tuple insert or
6599 * update that would have its own XLOG record that must follow the NEXTOID
6600 * record. Therefore, the standard buffer LSN interlock applied to those
6601 * records will ensure no such OID reaches disk before the NEXTOID record
6604 * Note, however, that the above statement only covers state "within" the
6605 * database. When we use a generated OID as a file or directory name, we
6606 * are in a sense violating the basic WAL rule, because that filesystem
6607 * change may reach disk before the NEXTOID WAL record does. The impact
6608 * of this is that if a database crash occurs immediately afterward, we
6609 * might after restart re-generate the same OID and find that it conflicts
6610 * with the leftover file or directory. But since for safety's sake we
6611 * always loop until finding a nonconflicting filename, this poses no real
6612 * problem in practice. See pgsql-hackers discussion 27-Sep-2006.
6617 * Write an XLOG SWITCH record.
6619 * Here we just blindly issue an XLogInsert request for the record.
6620 * All the magic happens inside XLogInsert.
6622 * The return value is either the end+1 address of the switch record,
6623 * or the end+1 address of the prior segment if we did not need to
6624 * write a switch record because we are already at segment start.
6627 RequestXLogSwitch(void)
6632 /* XLOG SWITCH, alone among xlog record types, has no data */
6633 rdata
.buffer
= InvalidBuffer
;
6638 RecPtr
= XLogInsert(RM_XLOG_ID
, XLOG_SWITCH
, &rdata
);
6644 * XLOG resource manager's routines
6646 * Definitions of info values are in include/catalog/pg_control.h, though
6647 * not all records types are related to control file processing.
6650 xlog_redo(XLogRecPtr lsn
, XLogRecord
*record
)
6652 uint8 info
= record
->xl_info
& ~XLR_INFO_MASK
;
6654 /* Backup blocks are not used in xlog records */
6655 Assert(!(record
->xl_info
& XLR_BKP_BLOCK_MASK
));
6657 if (info
== XLOG_NEXTOID
)
6661 memcpy(&nextOid
, XLogRecGetData(record
), sizeof(Oid
));
6662 if (ShmemVariableCache
->nextOid
< nextOid
)
6664 ShmemVariableCache
->nextOid
= nextOid
;
6665 ShmemVariableCache
->oidCount
= 0;
6668 else if (info
== XLOG_CHECKPOINT_SHUTDOWN
)
6670 CheckPoint checkPoint
;
6672 memcpy(&checkPoint
, XLogRecGetData(record
), sizeof(CheckPoint
));
6673 /* In a SHUTDOWN checkpoint, believe the counters exactly */
6674 ShmemVariableCache
->nextXid
= checkPoint
.nextXid
;
6675 ShmemVariableCache
->nextOid
= checkPoint
.nextOid
;
6676 ShmemVariableCache
->oidCount
= 0;
6677 MultiXactSetNextMXact(checkPoint
.nextMulti
,
6678 checkPoint
.nextMultiOffset
);
6680 /* ControlFile->checkPointCopy always tracks the latest ckpt XID */
6681 ControlFile
->checkPointCopy
.nextXidEpoch
= checkPoint
.nextXidEpoch
;
6682 ControlFile
->checkPointCopy
.nextXid
= checkPoint
.nextXid
;
6685 * TLI may change in a shutdown checkpoint, but it shouldn't decrease
6687 if (checkPoint
.ThisTimeLineID
!= ThisTimeLineID
)
6689 if (checkPoint
.ThisTimeLineID
< ThisTimeLineID
||
6690 !list_member_int(expectedTLIs
,
6691 (int) checkPoint
.ThisTimeLineID
))
6693 (errmsg("unexpected timeline ID %u (after %u) in checkpoint record",
6694 checkPoint
.ThisTimeLineID
, ThisTimeLineID
)));
6695 /* Following WAL records should be run with new TLI */
6696 ThisTimeLineID
= checkPoint
.ThisTimeLineID
;
6699 RecoveryRestartPoint(&checkPoint
);
6701 else if (info
== XLOG_CHECKPOINT_ONLINE
)
6703 CheckPoint checkPoint
;
6705 memcpy(&checkPoint
, XLogRecGetData(record
), sizeof(CheckPoint
));
6706 /* In an ONLINE checkpoint, treat the counters like NEXTOID */
6707 if (TransactionIdPrecedes(ShmemVariableCache
->nextXid
,
6708 checkPoint
.nextXid
))
6709 ShmemVariableCache
->nextXid
= checkPoint
.nextXid
;
6710 if (ShmemVariableCache
->nextOid
< checkPoint
.nextOid
)
6712 ShmemVariableCache
->nextOid
= checkPoint
.nextOid
;
6713 ShmemVariableCache
->oidCount
= 0;
6715 MultiXactAdvanceNextMXact(checkPoint
.nextMulti
,
6716 checkPoint
.nextMultiOffset
);
6718 /* ControlFile->checkPointCopy always tracks the latest ckpt XID */
6719 ControlFile
->checkPointCopy
.nextXidEpoch
= checkPoint
.nextXidEpoch
;
6720 ControlFile
->checkPointCopy
.nextXid
= checkPoint
.nextXid
;
6722 /* TLI should not change in an on-line checkpoint */
6723 if (checkPoint
.ThisTimeLineID
!= ThisTimeLineID
)
6725 (errmsg("unexpected timeline ID %u (should be %u) in checkpoint record",
6726 checkPoint
.ThisTimeLineID
, ThisTimeLineID
)));
6728 RecoveryRestartPoint(&checkPoint
);
6730 else if (info
== XLOG_NOOP
)
6732 /* nothing to do here */
6734 else if (info
== XLOG_SWITCH
)
6736 /* nothing to do here */
6741 xlog_desc(StringInfo buf
, uint8 xl_info
, char *rec
)
6743 uint8 info
= xl_info
& ~XLR_INFO_MASK
;
6745 if (info
== XLOG_CHECKPOINT_SHUTDOWN
||
6746 info
== XLOG_CHECKPOINT_ONLINE
)
6748 CheckPoint
*checkpoint
= (CheckPoint
*) rec
;
6750 appendStringInfo(buf
, "checkpoint: redo %X/%X; "
6751 "tli %u; xid %u/%u; oid %u; multi %u; offset %u; %s",
6752 checkpoint
->redo
.xlogid
, checkpoint
->redo
.xrecoff
,
6753 checkpoint
->ThisTimeLineID
,
6754 checkpoint
->nextXidEpoch
, checkpoint
->nextXid
,
6755 checkpoint
->nextOid
,
6756 checkpoint
->nextMulti
,
6757 checkpoint
->nextMultiOffset
,
6758 (info
== XLOG_CHECKPOINT_SHUTDOWN
) ? "shutdown" : "online");
6760 else if (info
== XLOG_NOOP
)
6762 appendStringInfo(buf
, "xlog no-op");
6764 else if (info
== XLOG_NEXTOID
)
6768 memcpy(&nextOid
, rec
, sizeof(Oid
));
6769 appendStringInfo(buf
, "nextOid: %u", nextOid
);
6771 else if (info
== XLOG_SWITCH
)
6773 appendStringInfo(buf
, "xlog switch");
6776 appendStringInfo(buf
, "UNKNOWN");
6782 xlog_outrec(StringInfo buf
, XLogRecord
*record
)
6786 appendStringInfo(buf
, "prev %X/%X; xid %u",
6787 record
->xl_prev
.xlogid
, record
->xl_prev
.xrecoff
,
6790 for (i
= 0; i
< XLR_MAX_BKP_BLOCKS
; i
++)
6792 if (record
->xl_info
& XLR_SET_BKP_BLOCK(i
))
6793 appendStringInfo(buf
, "; bkpb%d", i
+ 1);
6796 appendStringInfo(buf
, ": %s", RmgrTable
[record
->xl_rmid
].rm_name
);
6798 #endif /* WAL_DEBUG */
6802 * Return the (possible) sync flag used for opening a file, depending on the
6803 * value of the GUC wal_sync_method.
6806 get_sync_bit(int method
)
6808 /* If fsync is disabled, never open in sync mode */
6815 * enum values for all sync options are defined even if they are not
6816 * supported on the current platform. But if not, they are not
6817 * included in the enum option array, and therefore will never be seen
6820 case SYNC_METHOD_FSYNC
:
6821 case SYNC_METHOD_FSYNC_WRITETHROUGH
:
6822 case SYNC_METHOD_FDATASYNC
:
6824 #ifdef OPEN_SYNC_FLAG
6825 case SYNC_METHOD_OPEN
:
6826 return OPEN_SYNC_FLAG
;
6828 #ifdef OPEN_DATASYNC_FLAG
6829 case SYNC_METHOD_OPEN_DSYNC
:
6830 return OPEN_DATASYNC_FLAG
;
6833 /* can't happen (unless we are out of sync with option array) */
6834 elog(ERROR
, "unrecognized wal_sync_method: %d", method
);
6835 return 0; /* silence warning */
6843 assign_xlog_sync_method(int new_sync_method
, bool doit
, GucSource source
)
6848 if (sync_method
!= new_sync_method
)
6851 * To ensure that no blocks escape unsynced, force an fsync on the
6852 * currently open log segment (if any). Also, if the open flag is
6853 * changing, close the log file so it will be reopened (with new flag
6856 if (openLogFile
>= 0)
6858 if (pg_fsync(openLogFile
) != 0)
6860 (errcode_for_file_access(),
6861 errmsg("could not fsync log file %u, segment %u: %m",
6862 openLogId
, openLogSeg
)));
6863 if (get_sync_bit(sync_method
) != get_sync_bit(new_sync_method
))
6873 * Issue appropriate kind of fsync (if any) on the current XLOG output file
6876 issue_xlog_fsync(void)
6878 switch (sync_method
)
6880 case SYNC_METHOD_FSYNC
:
6881 if (pg_fsync_no_writethrough(openLogFile
) != 0)
6883 (errcode_for_file_access(),
6884 errmsg("could not fsync log file %u, segment %u: %m",
6885 openLogId
, openLogSeg
)));
6887 #ifdef HAVE_FSYNC_WRITETHROUGH
6888 case SYNC_METHOD_FSYNC_WRITETHROUGH
:
6889 if (pg_fsync_writethrough(openLogFile
) != 0)
6891 (errcode_for_file_access(),
6892 errmsg("could not fsync write-through log file %u, segment %u: %m",
6893 openLogId
, openLogSeg
)));
6896 #ifdef HAVE_FDATASYNC
6897 case SYNC_METHOD_FDATASYNC
:
6898 if (pg_fdatasync(openLogFile
) != 0)
6900 (errcode_for_file_access(),
6901 errmsg("could not fdatasync log file %u, segment %u: %m",
6902 openLogId
, openLogSeg
)));
6905 case SYNC_METHOD_OPEN
:
6906 case SYNC_METHOD_OPEN_DSYNC
:
6907 /* write synced it already */
6910 elog(PANIC
, "unrecognized wal_sync_method: %d", sync_method
);
6917 * pg_start_backup: set up for taking an on-line backup dump
6919 * Essentially what this does is to create a backup label file in $PGDATA,
6920 * where it will be archived as part of the backup dump. The label file
6921 * contains the user-supplied label string (typically this would be used
6922 * to tell where the backup dump will be stored) and the starting time and
6923 * starting WAL location for the dump.
6926 pg_start_backup(PG_FUNCTION_ARGS
)
6928 text
*backupid
= PG_GETARG_TEXT_P(0);
6929 bool fast
= PG_GETARG_BOOL(1);
6931 XLogRecPtr checkpointloc
;
6932 XLogRecPtr startpoint
;
6933 pg_time_t stamp_time
;
6935 char xlogfilename
[MAXFNAMELEN
];
6938 struct stat stat_buf
;
6943 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE
),
6944 errmsg("must be superuser to run a backup")));
6946 if (!XLogArchivingActive())
6948 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE
),
6949 errmsg("WAL archiving is not active"),
6950 errhint("archive_mode must be enabled at server start.")));
6952 if (!XLogArchiveCommandSet())
6954 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE
),
6955 errmsg("WAL archiving is not active"),
6956 errhint("archive_command must be defined before "
6957 "online backups can be made safely.")));
6959 backupidstr
= text_to_cstring(backupid
);
6962 * Mark backup active in shared memory. We must do full-page WAL writes
6963 * during an on-line backup even if not doing so at other times, because
6964 * it's quite possible for the backup dump to obtain a "torn" (partially
6965 * written) copy of a database page if it reads the page concurrently with
6966 * our write to the same page. This can be fixed as long as the first
6967 * write to the page in the WAL sequence is a full-page write. Hence, we
6968 * turn on forcePageWrites and then force a CHECKPOINT, to ensure there
6969 * are no dirty pages in shared memory that might get dumped while the
6970 * backup is in progress without having a corresponding WAL record. (Once
6971 * the backup is complete, we need not force full-page writes anymore,
6972 * since we expect that any pages not modified during the backup interval
6973 * must have been correctly captured by the backup.)
6975 * We must hold WALInsertLock to change the value of forcePageWrites, to
6976 * ensure adequate interlocking against XLogInsert().
6978 LWLockAcquire(WALInsertLock
, LW_EXCLUSIVE
);
6979 if (XLogCtl
->Insert
.forcePageWrites
)
6981 LWLockRelease(WALInsertLock
);
6983 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE
),
6984 errmsg("a backup is already in progress"),
6985 errhint("Run pg_stop_backup() and try again.")));
6987 XLogCtl
->Insert
.forcePageWrites
= true;
6988 LWLockRelease(WALInsertLock
);
6990 /* Ensure we release forcePageWrites if fail below */
6991 PG_ENSURE_ERROR_CLEANUP(pg_start_backup_callback
, (Datum
) 0);
6994 * Force a CHECKPOINT. Aside from being necessary to prevent torn
6995 * page problems, this guarantees that two successive backup runs will
6996 * have different checkpoint positions and hence different history
6997 * file names, even if nothing happened in between.
6999 * We use CHECKPOINT_IMMEDIATE only if requested by user (via
7000 * passing fast = true). Otherwise this can take awhile.
7002 RequestCheckpoint(CHECKPOINT_FORCE
| CHECKPOINT_WAIT
|
7003 (fast
? CHECKPOINT_IMMEDIATE
: 0));
7006 * Now we need to fetch the checkpoint record location, and also its
7007 * REDO pointer. The oldest point in WAL that would be needed to
7008 * restore starting from the checkpoint is precisely the REDO pointer.
7010 LWLockAcquire(ControlFileLock
, LW_EXCLUSIVE
);
7011 checkpointloc
= ControlFile
->checkPoint
;
7012 startpoint
= ControlFile
->checkPointCopy
.redo
;
7013 LWLockRelease(ControlFileLock
);
7015 XLByteToSeg(startpoint
, _logId
, _logSeg
);
7016 XLogFileName(xlogfilename
, ThisTimeLineID
, _logId
, _logSeg
);
7018 /* Use the log timezone here, not the session timezone */
7019 stamp_time
= (pg_time_t
) time(NULL
);
7020 pg_strftime(strfbuf
, sizeof(strfbuf
),
7021 "%Y-%m-%d %H:%M:%S %Z",
7022 pg_localtime(&stamp_time
, log_timezone
));
7025 * Check for existing backup label --- implies a backup is already
7026 * running. (XXX given that we checked forcePageWrites above, maybe
7027 * it would be OK to just unlink any such label file?)
7029 if (stat(BACKUP_LABEL_FILE
, &stat_buf
) != 0)
7031 if (errno
!= ENOENT
)
7033 (errcode_for_file_access(),
7034 errmsg("could not stat file \"%s\": %m",
7035 BACKUP_LABEL_FILE
)));
7039 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE
),
7040 errmsg("a backup is already in progress"),
7041 errhint("If you're sure there is no backup in progress, remove file \"%s\" and try again.",
7042 BACKUP_LABEL_FILE
)));
7045 * Okay, write the file
7047 fp
= AllocateFile(BACKUP_LABEL_FILE
, "w");
7050 (errcode_for_file_access(),
7051 errmsg("could not create file \"%s\": %m",
7052 BACKUP_LABEL_FILE
)));
7053 fprintf(fp
, "START WAL LOCATION: %X/%X (file %s)\n",
7054 startpoint
.xlogid
, startpoint
.xrecoff
, xlogfilename
);
7055 fprintf(fp
, "CHECKPOINT LOCATION: %X/%X\n",
7056 checkpointloc
.xlogid
, checkpointloc
.xrecoff
);
7057 fprintf(fp
, "START TIME: %s\n", strfbuf
);
7058 fprintf(fp
, "LABEL: %s\n", backupidstr
);
7059 if (fflush(fp
) || ferror(fp
) || FreeFile(fp
))
7061 (errcode_for_file_access(),
7062 errmsg("could not write file \"%s\": %m",
7063 BACKUP_LABEL_FILE
)));
7065 PG_END_ENSURE_ERROR_CLEANUP(pg_start_backup_callback
, (Datum
) 0);
7068 * We're done. As a convenience, return the starting WAL location.
7070 snprintf(xlogfilename
, sizeof(xlogfilename
), "%X/%X",
7071 startpoint
.xlogid
, startpoint
.xrecoff
);
7072 PG_RETURN_TEXT_P(cstring_to_text(xlogfilename
));
7075 /* Error cleanup callback for pg_start_backup */
7077 pg_start_backup_callback(int code
, Datum arg
)
7079 /* Turn off forcePageWrites on failure */
7080 LWLockAcquire(WALInsertLock
, LW_EXCLUSIVE
);
7081 XLogCtl
->Insert
.forcePageWrites
= false;
7082 LWLockRelease(WALInsertLock
);
7086 * pg_stop_backup: finish taking an on-line backup dump
7088 * We remove the backup label file created by pg_start_backup, and instead
7089 * create a backup history file in pg_xlog (whence it will immediately be
7090 * archived). The backup history file contains the same info found in
7091 * the label file, plus the backup-end time and WAL location.
7092 * Note: different from CancelBackup which just cancels online backup mode.
7095 pg_stop_backup(PG_FUNCTION_ARGS
)
7097 XLogRecPtr startpoint
;
7098 XLogRecPtr stoppoint
;
7099 pg_time_t stamp_time
;
7101 char histfilepath
[MAXPGPATH
];
7102 char startxlogfilename
[MAXFNAMELEN
];
7103 char stopxlogfilename
[MAXFNAMELEN
];
7104 char lastxlogfilename
[MAXFNAMELEN
];
7105 char histfilename
[MAXFNAMELEN
];
7112 int seconds_before_warning
;
7117 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE
),
7118 (errmsg("must be superuser to run a backup"))));
7120 if (!XLogArchivingActive())
7122 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE
),
7123 errmsg("WAL archiving is not active"),
7124 errhint("archive_mode must be enabled at server start.")));
7127 * OK to clear forcePageWrites
7129 LWLockAcquire(WALInsertLock
, LW_EXCLUSIVE
);
7130 XLogCtl
->Insert
.forcePageWrites
= false;
7131 LWLockRelease(WALInsertLock
);
7134 * Force a switch to a new xlog segment file, so that the backup is valid
7135 * as soon as archiver moves out the current segment file. We'll report
7136 * the end address of the XLOG SWITCH record as the backup stopping point.
7138 stoppoint
= RequestXLogSwitch();
7140 XLByteToSeg(stoppoint
, _logId
, _logSeg
);
7141 XLogFileName(stopxlogfilename
, ThisTimeLineID
, _logId
, _logSeg
);
7143 /* Use the log timezone here, not the session timezone */
7144 stamp_time
= (pg_time_t
) time(NULL
);
7145 pg_strftime(strfbuf
, sizeof(strfbuf
),
7146 "%Y-%m-%d %H:%M:%S %Z",
7147 pg_localtime(&stamp_time
, log_timezone
));
7150 * Open the existing label file
7152 lfp
= AllocateFile(BACKUP_LABEL_FILE
, "r");
7155 if (errno
!= ENOENT
)
7157 (errcode_for_file_access(),
7158 errmsg("could not read file \"%s\": %m",
7159 BACKUP_LABEL_FILE
)));
7161 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE
),
7162 errmsg("a backup is not in progress")));
7166 * Read and parse the START WAL LOCATION line (this code is pretty crude,
7167 * but we are not expecting any variability in the file format).
7169 if (fscanf(lfp
, "START WAL LOCATION: %X/%X (file %24s)%c",
7170 &startpoint
.xlogid
, &startpoint
.xrecoff
, startxlogfilename
,
7171 &ch
) != 4 || ch
!= '\n')
7173 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE
),
7174 errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE
)));
7177 * Write the backup history file
7179 XLByteToSeg(startpoint
, _logId
, _logSeg
);
7180 BackupHistoryFilePath(histfilepath
, ThisTimeLineID
, _logId
, _logSeg
,
7181 startpoint
.xrecoff
% XLogSegSize
);
7182 fp
= AllocateFile(histfilepath
, "w");
7185 (errcode_for_file_access(),
7186 errmsg("could not create file \"%s\": %m",
7188 fprintf(fp
, "START WAL LOCATION: %X/%X (file %s)\n",
7189 startpoint
.xlogid
, startpoint
.xrecoff
, startxlogfilename
);
7190 fprintf(fp
, "STOP WAL LOCATION: %X/%X (file %s)\n",
7191 stoppoint
.xlogid
, stoppoint
.xrecoff
, stopxlogfilename
);
7192 /* transfer remaining lines from label to history file */
7193 while ((ich
= fgetc(lfp
)) != EOF
)
7195 fprintf(fp
, "STOP TIME: %s\n", strfbuf
);
7196 if (fflush(fp
) || ferror(fp
) || FreeFile(fp
))
7198 (errcode_for_file_access(),
7199 errmsg("could not write file \"%s\": %m",
7203 * Close and remove the backup label file
7205 if (ferror(lfp
) || FreeFile(lfp
))
7207 (errcode_for_file_access(),
7208 errmsg("could not read file \"%s\": %m",
7209 BACKUP_LABEL_FILE
)));
7210 if (unlink(BACKUP_LABEL_FILE
) != 0)
7212 (errcode_for_file_access(),
7213 errmsg("could not remove file \"%s\": %m",
7214 BACKUP_LABEL_FILE
)));
7217 * Clean out any no-longer-needed history files. As a side effect, this
7218 * will post a .ready file for the newly created history file, notifying
7219 * the archiver that history file may be archived immediately.
7221 CleanupBackupHistory();
7224 * Wait until both the last WAL file filled during backup and the history
7225 * file have been archived. We assume that the alphabetic sorting
7226 * property of the WAL files ensures any earlier WAL files are safely
7229 * We wait forever, since archive_command is supposed to work and
7230 * we assume the admin wanted his backup to work completely. If you
7231 * don't wish to wait, you can set statement_timeout.
7233 XLByteToPrevSeg(stoppoint
, _logId
, _logSeg
);
7234 XLogFileName(lastxlogfilename
, ThisTimeLineID
, _logId
, _logSeg
);
7236 XLByteToSeg(startpoint
, _logId
, _logSeg
);
7237 BackupHistoryFileName(histfilename
, ThisTimeLineID
, _logId
, _logSeg
,
7238 startpoint
.xrecoff
% XLogSegSize
);
7240 seconds_before_warning
= 60;
7243 while (XLogArchiveIsBusy(lastxlogfilename
) ||
7244 XLogArchiveIsBusy(histfilename
))
7246 CHECK_FOR_INTERRUPTS();
7248 pg_usleep(1000000L);
7250 if (++waits
>= seconds_before_warning
)
7252 seconds_before_warning
*= 2; /* This wraps in >10 years... */
7254 (errmsg("pg_stop_backup still waiting for archive to complete (%d seconds elapsed)",
7260 * We're done. As a convenience, return the ending WAL location.
7262 snprintf(stopxlogfilename
, sizeof(stopxlogfilename
), "%X/%X",
7263 stoppoint
.xlogid
, stoppoint
.xrecoff
);
7264 PG_RETURN_TEXT_P(cstring_to_text(stopxlogfilename
));
7268 * pg_switch_xlog: switch to next xlog file
7271 pg_switch_xlog(PG_FUNCTION_ARGS
)
7273 XLogRecPtr switchpoint
;
7274 char location
[MAXFNAMELEN
];
7278 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE
),
7279 (errmsg("must be superuser to switch transaction log files"))));
7281 switchpoint
= RequestXLogSwitch();
7284 * As a convenience, return the WAL location of the switch record
7286 snprintf(location
, sizeof(location
), "%X/%X",
7287 switchpoint
.xlogid
, switchpoint
.xrecoff
);
7288 PG_RETURN_TEXT_P(cstring_to_text(location
));
7292 * Report the current WAL write location (same format as pg_start_backup etc)
7294 * This is useful for determining how much of WAL is visible to an external
7295 * archiving process. Note that the data before this point is written out
7296 * to the kernel, but is not necessarily synced to disk.
7299 pg_current_xlog_location(PG_FUNCTION_ARGS
)
7301 char location
[MAXFNAMELEN
];
7303 /* Make sure we have an up-to-date local LogwrtResult */
7305 /* use volatile pointer to prevent code rearrangement */
7306 volatile XLogCtlData
*xlogctl
= XLogCtl
;
7308 SpinLockAcquire(&xlogctl
->info_lck
);
7309 LogwrtResult
= xlogctl
->LogwrtResult
;
7310 SpinLockRelease(&xlogctl
->info_lck
);
7313 snprintf(location
, sizeof(location
), "%X/%X",
7314 LogwrtResult
.Write
.xlogid
, LogwrtResult
.Write
.xrecoff
);
7315 PG_RETURN_TEXT_P(cstring_to_text(location
));
7319 * Report the current WAL insert location (same format as pg_start_backup etc)
7321 * This function is mostly for debugging purposes.
7324 pg_current_xlog_insert_location(PG_FUNCTION_ARGS
)
7326 XLogCtlInsert
*Insert
= &XLogCtl
->Insert
;
7327 XLogRecPtr current_recptr
;
7328 char location
[MAXFNAMELEN
];
7331 * Get the current end-of-WAL position ... shared lock is sufficient
7333 LWLockAcquire(WALInsertLock
, LW_SHARED
);
7334 INSERT_RECPTR(current_recptr
, Insert
, Insert
->curridx
);
7335 LWLockRelease(WALInsertLock
);
7337 snprintf(location
, sizeof(location
), "%X/%X",
7338 current_recptr
.xlogid
, current_recptr
.xrecoff
);
7339 PG_RETURN_TEXT_P(cstring_to_text(location
));
7343 * Compute an xlog file name and decimal byte offset given a WAL location,
7344 * such as is returned by pg_stop_backup() or pg_xlog_switch().
7346 * Note that a location exactly at a segment boundary is taken to be in
7347 * the previous segment. This is usually the right thing, since the
7348 * expected usage is to determine which xlog file(s) are ready to archive.
7351 pg_xlogfile_name_offset(PG_FUNCTION_ARGS
)
7353 text
*location
= PG_GETARG_TEXT_P(0);
7355 unsigned int uxlogid
;
7356 unsigned int uxrecoff
;
7360 XLogRecPtr locationpoint
;
7361 char xlogfilename
[MAXFNAMELEN
];
7364 TupleDesc resultTupleDesc
;
7365 HeapTuple resultHeapTuple
;
7369 * Read input and parse
7371 locationstr
= text_to_cstring(location
);
7373 if (sscanf(locationstr
, "%X/%X", &uxlogid
, &uxrecoff
) != 2)
7375 (errcode(ERRCODE_INVALID_PARAMETER_VALUE
),
7376 errmsg("could not parse transaction log location \"%s\"",
7379 locationpoint
.xlogid
= uxlogid
;
7380 locationpoint
.xrecoff
= uxrecoff
;
7383 * Construct a tuple descriptor for the result row. This must match this
7384 * function's pg_proc entry!
7386 resultTupleDesc
= CreateTemplateTupleDesc(2, false);
7387 TupleDescInitEntry(resultTupleDesc
, (AttrNumber
) 1, "file_name",
7389 TupleDescInitEntry(resultTupleDesc
, (AttrNumber
) 2, "file_offset",
7392 resultTupleDesc
= BlessTupleDesc(resultTupleDesc
);
7397 XLByteToPrevSeg(locationpoint
, xlogid
, xlogseg
);
7398 XLogFileName(xlogfilename
, ThisTimeLineID
, xlogid
, xlogseg
);
7400 values
[0] = CStringGetTextDatum(xlogfilename
);
7406 xrecoff
= locationpoint
.xrecoff
- xlogseg
* XLogSegSize
;
7408 values
[1] = UInt32GetDatum(xrecoff
);
7412 * Tuple jam: Having first prepared your Datums, then squash together
7414 resultHeapTuple
= heap_form_tuple(resultTupleDesc
, values
, isnull
);
7416 result
= HeapTupleGetDatum(resultHeapTuple
);
7418 PG_RETURN_DATUM(result
);
7422 * Compute an xlog file name given a WAL location,
7423 * such as is returned by pg_stop_backup() or pg_xlog_switch().
7426 pg_xlogfile_name(PG_FUNCTION_ARGS
)
7428 text
*location
= PG_GETARG_TEXT_P(0);
7430 unsigned int uxlogid
;
7431 unsigned int uxrecoff
;
7434 XLogRecPtr locationpoint
;
7435 char xlogfilename
[MAXFNAMELEN
];
7437 locationstr
= text_to_cstring(location
);
7439 if (sscanf(locationstr
, "%X/%X", &uxlogid
, &uxrecoff
) != 2)
7441 (errcode(ERRCODE_INVALID_PARAMETER_VALUE
),
7442 errmsg("could not parse transaction log location \"%s\"",
7445 locationpoint
.xlogid
= uxlogid
;
7446 locationpoint
.xrecoff
= uxrecoff
;
7448 XLByteToPrevSeg(locationpoint
, xlogid
, xlogseg
);
7449 XLogFileName(xlogfilename
, ThisTimeLineID
, xlogid
, xlogseg
);
7451 PG_RETURN_TEXT_P(cstring_to_text(xlogfilename
));
7455 * read_backup_label: check to see if a backup_label file is present
7457 * If we see a backup_label during recovery, we assume that we are recovering
7458 * from a backup dump file, and we therefore roll forward from the checkpoint
7459 * identified by the label file, NOT what pg_control says. This avoids the
7460 * problem that pg_control might have been archived one or more checkpoints
7461 * later than the start of the dump, and so if we rely on it as the start
7462 * point, we will fail to restore a consistent database state.
7464 * We also attempt to retrieve the corresponding backup history file.
7465 * If successful, set *minRecoveryLoc to constrain valid PITR stopping
7468 * Returns TRUE if a backup_label was found (and fills the checkpoint
7469 * location into *checkPointLoc); returns FALSE if not.
7472 read_backup_label(XLogRecPtr
*checkPointLoc
, XLogRecPtr
*minRecoveryLoc
)
7474 XLogRecPtr startpoint
;
7475 XLogRecPtr stoppoint
;
7476 char histfilename
[MAXFNAMELEN
];
7477 char histfilepath
[MAXPGPATH
];
7478 char startxlogfilename
[MAXFNAMELEN
];
7479 char stopxlogfilename
[MAXFNAMELEN
];
7487 /* Default is to not constrain recovery stop point */
7488 minRecoveryLoc
->xlogid
= 0;
7489 minRecoveryLoc
->xrecoff
= 0;
7492 * See if label file is present
7494 lfp
= AllocateFile(BACKUP_LABEL_FILE
, "r");
7497 if (errno
!= ENOENT
)
7499 (errcode_for_file_access(),
7500 errmsg("could not read file \"%s\": %m",
7501 BACKUP_LABEL_FILE
)));
7502 return false; /* it's not there, all is fine */
7506 * Read and parse the START WAL LOCATION and CHECKPOINT lines (this code
7507 * is pretty crude, but we are not expecting any variability in the file
7510 if (fscanf(lfp
, "START WAL LOCATION: %X/%X (file %08X%16s)%c",
7511 &startpoint
.xlogid
, &startpoint
.xrecoff
, &tli
,
7512 startxlogfilename
, &ch
) != 5 || ch
!= '\n')
7514 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE
),
7515 errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE
)));
7516 if (fscanf(lfp
, "CHECKPOINT LOCATION: %X/%X%c",
7517 &checkPointLoc
->xlogid
, &checkPointLoc
->xrecoff
,
7518 &ch
) != 3 || ch
!= '\n')
7520 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE
),
7521 errmsg("invalid data in file \"%s\"", BACKUP_LABEL_FILE
)));
7522 if (ferror(lfp
) || FreeFile(lfp
))
7524 (errcode_for_file_access(),
7525 errmsg("could not read file \"%s\": %m",
7526 BACKUP_LABEL_FILE
)));
7529 * Try to retrieve the backup history file (no error if we can't)
7531 XLByteToSeg(startpoint
, _logId
, _logSeg
);
7532 BackupHistoryFileName(histfilename
, tli
, _logId
, _logSeg
,
7533 startpoint
.xrecoff
% XLogSegSize
);
7535 if (InArchiveRecovery
)
7536 RestoreArchivedFile(histfilepath
, histfilename
, "RECOVERYHISTORY", 0);
7538 BackupHistoryFilePath(histfilepath
, tli
, _logId
, _logSeg
,
7539 startpoint
.xrecoff
% XLogSegSize
);
7541 fp
= AllocateFile(histfilepath
, "r");
7545 * Parse history file to identify stop point.
7547 if (fscanf(fp
, "START WAL LOCATION: %X/%X (file %24s)%c",
7548 &startpoint
.xlogid
, &startpoint
.xrecoff
, startxlogfilename
,
7549 &ch
) != 4 || ch
!= '\n')
7551 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE
),
7552 errmsg("invalid data in file \"%s\"", histfilename
)));
7553 if (fscanf(fp
, "STOP WAL LOCATION: %X/%X (file %24s)%c",
7554 &stoppoint
.xlogid
, &stoppoint
.xrecoff
, stopxlogfilename
,
7555 &ch
) != 4 || ch
!= '\n')
7557 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE
),
7558 errmsg("invalid data in file \"%s\"", histfilename
)));
7559 *minRecoveryLoc
= stoppoint
;
7560 if (ferror(fp
) || FreeFile(fp
))
7562 (errcode_for_file_access(),
7563 errmsg("could not read file \"%s\": %m",
7571 * Error context callback for errors occurring during rm_redo().
7574 rm_redo_error_callback(void *arg
)
7576 XLogRecord
*record
= (XLogRecord
*) arg
;
7579 initStringInfo(&buf
);
7580 RmgrTable
[record
->xl_rmid
].rm_desc(&buf
,
7582 XLogRecGetData(record
));
7584 /* don't bother emitting empty description */
7586 errcontext("xlog redo %s", buf
.data
);
7592 * BackupInProgress: check if online backup mode is active
7594 * This is done by checking for existence of the "backup_label" file.
7597 BackupInProgress(void)
7599 struct stat stat_buf
;
7601 return (stat(BACKUP_LABEL_FILE
, &stat_buf
) == 0);
7605 * CancelBackup: rename the "backup_label" file to cancel backup mode
7607 * If the "backup_label" file exists, it will be renamed to "backup_label.old".
7608 * Note that this will render an online backup in progress useless.
7609 * To correctly finish an online backup, pg_stop_backup must be called.
7614 struct stat stat_buf
;
7616 /* if the file is not there, return */
7617 if (stat(BACKUP_LABEL_FILE
, &stat_buf
) < 0)
7620 /* remove leftover file from previously cancelled backup if it exists */
7621 unlink(BACKUP_LABEL_OLD
);
7623 if (rename(BACKUP_LABEL_FILE
, BACKUP_LABEL_OLD
) == 0)
7626 (errmsg("online backup mode cancelled"),
7627 errdetail("\"%s\" was renamed to \"%s\".",
7628 BACKUP_LABEL_FILE
, BACKUP_LABEL_OLD
)));
7633 (errcode_for_file_access(),
7634 errmsg("online backup mode was not cancelled"),
7635 errdetail("Could not rename \"%s\" to \"%s\": %m.",
7636 BACKUP_LABEL_FILE
, BACKUP_LABEL_OLD
)));
7640 /* ------------------------------------------------------
7641 * Startup Process main entry point and signal handlers
7642 * ------------------------------------------------------
7646 * startupproc_quickdie() occurs when signalled SIGQUIT by the postmaster.
7648 * Some backend has bought the farm,
7649 * so we need to stop what we're doing and exit.
7652 startupproc_quickdie(SIGNAL_ARGS
)
7654 PG_SETMASK(&BlockSig
);
7657 * DO NOT proc_exit() -- we're here because shared memory may be
7658 * corrupted, so we don't want to try to clean up our transaction. Just
7659 * nail the windows shut and get out of town.
7661 * Note we do exit(2) not exit(0). This is to force the postmaster into a
7662 * system reset cycle if some idiot DBA sends a manual SIGQUIT to a random
7663 * backend. This is necessary precisely because we don't clean up our
7664 * shared memory state.
7670 /* SIGHUP: set flag to re-read config file at next convenient time */
7672 StartupProcSigHupHandler(SIGNAL_ARGS
)
7677 /* SIGTERM: set flag to abort redo and exit */
7679 StartupProcShutdownHandler(SIGNAL_ARGS
)
7681 if (in_restore_command
)
7684 shutdown_requested
= true;
7687 /* Main entry point for startup process */
7689 StartupProcessMain(void)
7692 * If possible, make this process a group leader, so that the postmaster
7693 * can signal any child processes too.
7697 elog(FATAL
, "setsid() failed: %m");
7701 * Properly accept or ignore signals the postmaster might send us
7703 pqsignal(SIGHUP
, StartupProcSigHupHandler
); /* reload config file */
7704 pqsignal(SIGINT
, SIG_IGN
); /* ignore query cancel */
7705 pqsignal(SIGTERM
, StartupProcShutdownHandler
); /* request shutdown */
7706 pqsignal(SIGQUIT
, startupproc_quickdie
); /* hard crash time */
7707 pqsignal(SIGALRM
, SIG_IGN
);
7708 pqsignal(SIGPIPE
, SIG_IGN
);
7709 pqsignal(SIGUSR1
, SIG_IGN
);
7710 pqsignal(SIGUSR2
, SIG_IGN
);
7713 * Reset some signals that are accepted by postmaster but not here
7715 pqsignal(SIGCHLD
, SIG_DFL
);
7716 pqsignal(SIGTTIN
, SIG_DFL
);
7717 pqsignal(SIGTTOU
, SIG_DFL
);
7718 pqsignal(SIGCONT
, SIG_DFL
);
7719 pqsignal(SIGWINCH
, SIG_DFL
);
7722 * Unblock signals (they were blocked when the postmaster forked us)
7724 PG_SETMASK(&UnBlockSig
);
7728 BuildFlatFiles(false);
7731 * Exit normally. Exit code 0 tells postmaster that we completed
7732 * recovery successfully.