src/status.c

   1 /*
   2 ** 2008 June 18
   3 **
   4 ** The author disclaims copyright to this source code.  In place of
   5 ** a legal notice, here is a blessing:
   6 **
   7 **    May you do good and not evil.
   8 **    May you find forgiveness for yourself and forgive others.
   9 **    May you share freely, never taking more than you give.
  10 **
  11 *************************************************************************
  12 **
  13 ** This module implements the sqlite3_status() interface and related
  14 ** functionality.
  15 */
  16 #include "sqliteInt.h"
  17 #include "vdbeInt.h"
  18
  19 /*
  20 ** Variables in which to record status information.
  21 */
  22 typedef struct sqlite3StatType sqlite3StatType;
  23 static SQLITE_WSD struct sqlite3StatType {
  24   int nowValue[10];         /* Current value */
  25   int mxValue[10];          /* Maximum value */
  26 } sqlite3Stat = { {0,}, {0,} };
  27
  28
  29 /* The "wsdStat" macro will resolve to the status information
  30 ** state vector.  If writable static data is unsupported on the target,
  31 ** we have to locate the state vector at run-time.  In the more common
  32 ** case where writable static data is supported, wsdStat can refer directly
  33 ** to the "sqlite3Stat" state vector declared above.
  34 */
  35 #ifdef SQLITE_OMIT_WSD
  36 # define wsdStatInit  sqlite3StatType *x = &GLOBAL(sqlite3StatType,sqlite3Stat)
  37 # define wsdStat x[0]
  38 #else
  39 # define wsdStatInit
  40 # define wsdStat sqlite3Stat
  41 #endif
  42
  43 /*
  44 ** Return the current value of a status parameter.
  45 */
  46 int sqlite3StatusValue(int op){
  47   wsdStatInit;
  48   assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
  49   return wsdStat.nowValue[op];
  50 }
  51
  52 /*
  53 ** Add N to the value of a status record.  It is assumed that the
  54 ** caller holds appropriate locks.
  55 */
  56 void sqlite3StatusAdd(int op, int N){
  57   wsdStatInit;
  58   assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
  59   wsdStat.nowValue[op] += N;
  60   if( wsdStat.nowValue[op]>wsdStat.mxValue[op] ){
  61     wsdStat.mxValue[op] = wsdStat.nowValue[op];
  62   }
  63 }
  64
  65 /*
  66 ** Set the value of a status to X.
  67 */
  68 void sqlite3StatusSet(int op, int X){
  69   wsdStatInit;
  70   assert( op>=0 && op<ArraySize(wsdStat.nowValue) );
  71   wsdStat.nowValue[op] = X;
  72   if( wsdStat.nowValue[op]>wsdStat.mxValue[op] ){
  73     wsdStat.mxValue[op] = wsdStat.nowValue[op];
  74   }
  75 }
  76
  77 /*
  78 ** Query status information.
  79 **
  80 ** This implementation assumes that reading or writing an aligned
  81 ** 32-bit integer is an atomic operation.  If that assumption is not true,
  82 ** then this routine is not threadsafe.
  83 */
  84 int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag){
  85   wsdStatInit;
  86   if( op<0 || op>=ArraySize(wsdStat.nowValue) ){
  87     return SQLITE_MISUSE_BKPT;
  88   }
  89   *pCurrent = wsdStat.nowValue[op];
  90   *pHighwater = wsdStat.mxValue[op];
  91   if( resetFlag ){
  92     wsdStat.mxValue[op] = wsdStat.nowValue[op];
  93   }
  94   return SQLITE_OK;
  95 }
  96
  97 /*
  98 ** Query status information for a single database connection
  99 */
 100 int sqlite3_db_status(
 101   sqlite3 *db,          /* The database connection whose status is desired */
 102   int op,               /* Status verb */
 103   int *pCurrent,        /* Write current value here */
 104   int *pHighwater,      /* Write high-water mark here */
 105   int resetFlag         /* Reset high-water mark if true */
 106 ){
 107   int rc = SQLITE_OK;   /* Return code */
 108   sqlite3_mutex_enter(db->mutex);
 109   switch( op ){
 110     case SQLITE_DBSTATUS_LOOKASIDE_USED: {
 111       *pCurrent = db->lookaside.nOut;
 112       *pHighwater = db->lookaside.mxOut;
 113       if( resetFlag ){
 114         db->lookaside.mxOut = db->lookaside.nOut;
 115       }
 116       break;
 117     }
 118
 119     case SQLITE_DBSTATUS_LOOKASIDE_HIT:
 120     case SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE:
 121     case SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL: {
 122       testcase( op==SQLITE_DBSTATUS_LOOKASIDE_HIT );
 123       testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE );
 124       testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL );
 125       assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)>=0 );
 126       assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)<3 );
 127       *pCurrent = 0;
 128       *pHighwater = db->lookaside.anStat[op - SQLITE_DBSTATUS_LOOKASIDE_HIT];
 129       if( resetFlag ){
 130         db->lookaside.anStat[op - SQLITE_DBSTATUS_LOOKASIDE_HIT] = 0;
 131       }
 132       break;
 133     }
 134
 135     /*
 136     ** Return an approximation for the amount of memory currently used
 137     ** by all pagers associated with the given database connection.  The
 138     ** highwater mark is meaningless and is returned as zero.
 139     */
 140     case SQLITE_DBSTATUS_CACHE_USED: {
 141       int totalUsed = 0;
 142       int i;
 143       sqlite3BtreeEnterAll(db);
 144       for(i=0; i<db->nDb; i++){
 145         Btree *pBt = db->aDb[i].pBt;
 146         if( pBt ){
 147           Pager *pPager = sqlite3BtreePager(pBt);
 148           totalUsed += sqlite3PagerMemUsed(pPager);
 149         }
 150       }
 151       sqlite3BtreeLeaveAll(db);
 152       *pCurrent = totalUsed;
 153       *pHighwater = 0;
 154       break;
 155     }
 156
 157     /*
 158     ** *pCurrent gets an accurate estimate of the amount of memory used
 159     ** to store the schema for all databases (main, temp, and any ATTACHed
 160     ** databases.  *pHighwater is set to zero.
 161     */
 162     case SQLITE_DBSTATUS_SCHEMA_USED: {
 163       int i;                      /* Used to iterate through schemas */
 164       int nByte = 0;              /* Used to accumulate return value */
 165
 166       sqlite3BtreeEnterAll(db);
 167       db->pnBytesFreed = &nByte;
 168       for(i=0; i<db->nDb; i++){
 169         Schema *pSchema = db->aDb[i].pSchema;
 170         if( ALWAYS(pSchema!=0) ){
 171           HashElem *p;
 172
 173           nByte += sqlite3GlobalConfig.m.xRoundup(sizeof(HashElem)) * (
 174               pSchema->tblHash.count
 175             + pSchema->trigHash.count
 176             + pSchema->idxHash.count
 177             + pSchema->fkeyHash.count
 178           );
 179           nByte += sqlite3MallocSize(pSchema->tblHash.ht);
 180           nByte += sqlite3MallocSize(pSchema->trigHash.ht);
 181           nByte += sqlite3MallocSize(pSchema->idxHash.ht);
 182           nByte += sqlite3MallocSize(pSchema->fkeyHash.ht);
 183
 184           for(p=sqliteHashFirst(&pSchema->trigHash); p; p=sqliteHashNext(p)){
 185             sqlite3DeleteTrigger(db, (Trigger*)sqliteHashData(p));
 186           }
 187           for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
 188             sqlite3DeleteTable(db, (Table *)sqliteHashData(p));
 189           }
 190         }
 191       }
 192       db->pnBytesFreed = 0;
 193       sqlite3BtreeLeaveAll(db);
 194
 195       *pHighwater = 0;
 196       *pCurrent = nByte;
 197       break;
 198     }
 199
 200     /*
 201     ** *pCurrent gets an accurate estimate of the amount of memory used
 202     ** to store all prepared statements.
 203     ** *pHighwater is set to zero.
 204     */
 205     case SQLITE_DBSTATUS_STMT_USED: {
 206       struct Vdbe *pVdbe;         /* Used to iterate through VMs */
 207       int nByte = 0;              /* Used to accumulate return value */
 208
 209       db->pnBytesFreed = &nByte;
 210       for(pVdbe=db->pVdbe; pVdbe; pVdbe=pVdbe->pNext){
 211         sqlite3VdbeClearObject(db, pVdbe);
 212         sqlite3DbFree(db, pVdbe);
 213       }
 214       db->pnBytesFreed = 0;
 215
 216       *pHighwater = 0;
 217       *pCurrent = nByte;
 218
 219       break;
 220     }
 221
 222     /*
 223     ** Set *pCurrent to the total cache hits or misses encountered by all
 224     ** pagers the database handle is connected to. *pHighwater is always set
 225     ** to zero.
 226     */
 227     case SQLITE_DBSTATUS_CACHE_HIT:
 228     case SQLITE_DBSTATUS_CACHE_MISS:
 229     case SQLITE_DBSTATUS_CACHE_WRITE:{
 230       int i;
 231       int nRet = 0;
 232       assert( SQLITE_DBSTATUS_CACHE_MISS==SQLITE_DBSTATUS_CACHE_HIT+1 );
 233       assert( SQLITE_DBSTATUS_CACHE_WRITE==SQLITE_DBSTATUS_CACHE_HIT+2 );
 234
 235       for(i=0; i<db->nDb; i++){
 236         if( db->aDb[i].pBt ){
 237           Pager *pPager = sqlite3BtreePager(db->aDb[i].pBt);
 238           sqlite3PagerCacheStat(pPager, op, resetFlag, &nRet);
 239         }
 240       }
 241       *pHighwater = 0;
 242       *pCurrent = nRet;
 243       break;
 244     }
 245
 246     default: {
 247       rc = SQLITE_ERROR;
 248     }
 249   }
 250   sqlite3_mutex_leave(db->mutex);
 251   return rc;
 252 }