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Add the SQLITE_DB_STATUS_CACHE_HIT and MISS options. For querying the number of cache hits and misses on a per-connection basis.

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FossilOrigin-Name: 5100b6e9dc5107f0f835d0aac26fe6d4938ffc73
This commit is contained in:
dan
2011-09-22 14:41:16 +00:00
parent 0fe0c466ca
commit 58ca31c905
8 changed files with 160 additions and 20 deletions
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33
src/pager.c
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@@ -670,8 +670,8 @@ struct Pager {
char *zJournal; /* Name of the journal file */
int (*xBusyHandler)(void*); /* Function to call when busy */
void *pBusyHandlerArg; /* Context argument for xBusyHandler */
int nHit, nMiss; /* Total cache hits and misses */
#ifdef SQLITE_TEST
int nHit, nMiss; /* Cache hits and missing */
int nRead, nWrite; /* Database pages read/written */
#endif
void (*xReiniter)(DbPage*); /* Call this routine when reloading pages */
@@ -4169,7 +4169,7 @@ static int pagerStress(void *p, PgHdr *pPg){
**
** Spilling is also prohibited when in an error state since that could
** lead to database corruption. In the current implementaton it
** is impossible for sqlite3PCacheFetch() to be called with createFlag==1
** is impossible for sqlite3PcacheFetch() to be called with createFlag==1
** while in the error state, hence it is impossible for this routine to
** be called in the error state. Nevertheless, we include a NEVER()
** test for the error state as a safeguard against future changes.
@@ -5005,14 +5005,13 @@ int sqlite3PagerAcquire(
/* In this case the pcache already contains an initialized copy of
** the page. Return without further ado. */
assert( pgno<=PAGER_MAX_PGNO && pgno!=PAGER_MJ_PGNO(pPager) );
PAGER_INCR(pPager->nHit);
pPager->nHit++;
return SQLITE_OK;
}else{
/* The pager cache has created a new page. Its content needs to
** be initialized. */
PAGER_INCR(pPager->nMiss);
pPg = *ppPage;
pPg->pPager = pPager;
@@ -5048,6 +5047,7 @@ int sqlite3PagerAcquire(
IOTRACE(("ZERO %p %d\n", pPager, pgno));
}else{
assert( pPg->pPager==pPager );
pPager->nMiss++;
rc = readDbPage(pPg);
if( rc!=SQLITE_OK ){
goto pager_acquire_err;
@@ -6082,6 +6082,31 @@ int *sqlite3PagerStats(Pager *pPager){
}
#endif
/*
** Parameter eStat must be either SQLITE_DBSTATUS_CACHE_HIT or
** SQLITE_DBSTATUS_CACHE_MISS. Before returning, *pnVal is incremented by the
** current cache hit or miss count, according to the value of eStat. If the
** reset parameter is non-zero, the cache hit or miss count is zeroed before
** returning.
*/
void sqlite3PagerCacheStat(Pager *pPager, int eStat, int reset, int *pnVal){
int *piStat;
assert( eStat==SQLITE_DBSTATUS_CACHE_HIT
|| eStat==SQLITE_DBSTATUS_CACHE_MISS
);
if( eStat==SQLITE_DBSTATUS_CACHE_HIT ){
piStat = &pPager->nHit;
}else{
piStat = &pPager->nMiss;
}
*pnVal += *piStat;
if( reset ){
*piStat = 0;
}
}
/*
** Return true if this is an in-memory pager.
*/