db2/include/log.h

   1 /*-
   2  * See the file LICENSE for redistribution information.
   3  *
   4  * Copyright (c) 1996, 1997, 1998
   5  *      Sleepycat Software.  All rights reserved.
   6  *
   7  *      @(#)log.h       10.25 (Sleepycat) 4/10/98
   8  */
   9
  10 #ifndef _LOG_H_
  11 #define _LOG_H_
  12
  13 struct __fname;         typedef struct __fname FNAME;
  14 struct __hdr;           typedef struct __hdr HDR;
  15 struct __log;           typedef struct __log LOG;
  16 struct __log_persist;   typedef struct __log_persist LOGP;
  17
  18 #ifndef MAXLFNAME
  19 #define MAXLFNAME       99999           /* Maximum log file name. */
  20 #define LFNAME          "log.%05d"      /* Log file name template. */
  21 #endif
  22                                         /* Default log name. */
  23 #define DB_DEFAULT_LOG_FILE     "__db_log.share"
  24
  25 #define DEFAULT_MAX     (10 * MEGABYTE) /* 10 Mb. */
  26
  27 /* Macros to lock/unlock the region and threads. */
  28 #define LOCK_LOGTHREAD(dblp)                                            \
  29         if (F_ISSET(dblp, DB_AM_THREAD))                                \
  30                 (void)__db_mutex_lock((dblp)->mutexp, -1)
  31 #define UNLOCK_LOGTHREAD(dblp)                                          \
  32         if (F_ISSET(dblp, DB_AM_THREAD))                                \
  33                 (void)__db_mutex_unlock((dblp)->mutexp, -1);
  34 #define LOCK_LOGREGION(dblp)                                            \
  35         (void)__db_mutex_lock(&((RLAYOUT *)(dblp)->lp)->lock,           \
  36             (dblp)->reginfo.fd)
  37 #define UNLOCK_LOGREGION(dblp)                                          \
  38         (void)__db_mutex_unlock(&((RLAYOUT *)(dblp)->lp)->lock,         \
  39             (dblp)->reginfo.fd)
  40
  41 /*
  42  * The per-process table that maps log file-id's to DB structures.
  43  */
  44 typedef struct __db_entry {
  45         DB       *dbp;                  /* Associated DB structure. */
  46         u_int32_t refcount;             /* Reference counted. */
  47         int       deleted;              /* File was not found during open. */
  48 } DB_ENTRY;
  49
  50 /*
  51  * DB_LOG
  52  *      Per-process log structure.
  53  */
  54 struct __db_log {
  55 /* These fields need to be protected for multi-threaded support. */
  56         db_mutex_t      *mutexp;        /* Mutex for thread protection. */
  57
  58         DB_ENTRY *dbentry;              /* Recovery file-id mapping. */
  59 #define DB_GROW_SIZE    64
  60         u_int32_t dbentry_cnt;          /* Entries.  Grows by DB_GROW_SIZE. */
  61
  62 /*
  63  * These fields are always accessed while the region lock is held, so they do
  64  * not have to be protected by the thread lock as well OR, they are only used
  65  * when threads are not being used, i.e. most cursor operations are disallowed
  66  * on threaded logs.
  67  */
  68         u_int32_t lfname;               /* Log file "name". */
  69         int       lfd;                  /* Log file descriptor. */
  70
  71         DB_LSN    c_lsn;                /* Cursor: current LSN. */
  72         DBT       c_dbt;                /* Cursor: return DBT structure. */
  73         int       c_fd;                 /* Cursor: file descriptor. */
  74         u_int32_t c_off;                /* Cursor: previous record offset. */
  75         u_int32_t c_len;                /* Cursor: current record length. */
  76
  77 /* These fields are not protected. */
  78         LOG      *lp;                   /* Address of the shared LOG. */
  79
  80         DB_ENV   *dbenv;                /* Reference to error information. */
  81         REGINFO   reginfo;              /* Region information. */
  82
  83         void     *addr;                 /* Address of shalloc() region. */
  84
  85         char     *dir;                  /* Directory argument. */
  86
  87         u_int32_t flags;                /* Support the DB_AM_XXX flags. */
  88 };
  89
  90 /*
  91  * HDR --
  92  *      Log record header.
  93  */
  94 struct __hdr {
  95         u_int32_t prev;                 /* Previous offset. */
  96         u_int32_t cksum;                /* Current checksum. */
  97         u_int32_t len;                  /* Current length. */
  98 };
  99
 100 struct __log_persist {
 101         u_int32_t magic;                /* DB_LOGMAGIC */
 102         u_int32_t version;              /* DB_LOGVERSION */
 103
 104         u_int32_t lg_max;               /* Maximum file size. */
 105         int       mode;                 /* Log file mode. */
 106 };
 107
 108 /*
 109  * LOG --
 110  *      Shared log region.  One of these is allocated in shared memory,
 111  *      and describes the log.
 112  */
 113 struct __log {
 114         RLAYOUT   rlayout;              /* General region information. */
 115
 116         LOGP      persist;              /* Persistent information. */
 117
 118         SH_TAILQ_HEAD(__fq) fq;         /* List of file names. */
 119
 120         /*
 121          * The lsn LSN is the file offset that we're about to write and which
 122          * we will return to the user.
 123          */
 124         DB_LSN    lsn;                  /* LSN at current file offset. */
 125
 126         /*
 127          * The s_lsn LSN is the last LSN that we know is on disk, not just
 128          * written, but synced.
 129          */
 130         DB_LSN    s_lsn;                /* LSN of the last sync. */
 131
 132         u_int32_t len;                  /* Length of the last record. */
 133
 134         u_int32_t w_off;                /* Current write offset in the file. */
 135
 136         DB_LSN    chkpt_lsn;            /* LSN of the last checkpoint. */
 137         time_t    chkpt;                /* Time of the last checkpoint. */
 138
 139         DB_LOG_STAT stat;               /* Log statistics. */
 140
 141         /*
 142          * The f_lsn LSN is the LSN (returned to the user) that "owns" the
 143          * first byte of the buffer.  If the record associated with the LSN
 144          * spans buffers, it may not reflect the physical file location of
 145          * the first byte of the buffer.
 146          */
 147         DB_LSN    f_lsn;                /* LSN of first byte in the buffer. */
 148         size_t    b_off;                /* Current offset in the buffer. */
 149         u_int8_t buf[4 * 1024];         /* Log buffer. */
 150 };
 151
 152 /*
 153  * FNAME --
 154  *      File name and id.
 155  */
 156 struct __fname {
 157         SH_TAILQ_ENTRY q;               /* File name queue. */
 158
 159         u_int16_t ref;                  /* Reference count. */
 160
 161         u_int32_t id;                   /* Logging file id. */
 162         DBTYPE    s_type;               /* Saved DB type. */
 163
 164         size_t    name_off;             /* Name offset. */
 165         u_int8_t  ufid[DB_FILE_ID_LEN]; /* Unique file id. */
 166 };
 167
 168 /* File open/close register log record opcodes. */
 169 #define LOG_CHECKPOINT  1               /* Checkpoint: file name/id dump. */
 170 #define LOG_CLOSE       2               /* File close. */
 171 #define LOG_OPEN        3               /* File open. */
 172
 173 #include "log_auto.h"
 174 #include "log_ext.h"
 175 #endif /* _LOG_H_ */