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Overview
| Comment: | Try to make pcache1TruncateUnsafe() run faster for the case where iLimit is very close to iMaxKey. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | debug |
| Files: | files | file ages | folders |
| SHA1: |
9ab53605d562a926c5620cba9dc96a3b |
| User & Date: | drh 2016-08-10 03:35:50.389 |
Context
|
2016-08-10
| ||
| 11:50 | Fix pcache1TruncateUnsafe() run faster for the case where iLimit is very close to iMaxKey. (check-in: b07a26df06 user: drh tags: trunk) | |
| 03:35 | Try to make pcache1TruncateUnsafe() run faster for the case where iLimit is very close to iMaxKey. (Leaf check-in: 9ab53605d5 user: drh tags: debug) | |
| 02:54 | Remove all timers and other debugging logs except for the one timer on pcache1TruncateUnsafe(). (check-in: 5980e625db user: drh tags: debug) | |
Changes
Changes to src/pcache1.c.
| ︙ | ︙ | |||
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**
** The PCache mutex must be held when this function is called.
*/
static void pcache1TruncateUnsafe(
PCache1 *pCache, /* The cache to truncate */
unsigned int iLimit /* Drop pages with this pgno or larger */
){
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**
** The PCache mutex must be held when this function is called.
*/
static void pcache1TruncateUnsafe(
PCache1 *pCache, /* The cache to truncate */
unsigned int iLimit /* Drop pages with this pgno or larger */
){
TESTONLY( int nPage = 0; ) /* To assert pCache->nPage is correct */
unsigned int h, iStop;
START_DEBUG_TIMER;
int nFree = 0;
assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
assert( pCache->iMaxKey >= iLimit );
assert( pCache->nHash > 0 );
if( pCache->iMaxKey - iLimit < pCache->nHash/2 ){
/* If we are just shaving the last few pages off the end of the
** cache, then there is no point in scanning the entire hash table.
** Only scan those hash slots that might contain pages that need to
** be removed. */
iStop = iLimit % pCache->nHash;
h = pCache->iMaxKey % pCache->nHash;
TESTONLY( nPage = -10; ) /* Disable the pCache->nPage validity check */
}else{
/* This is the general case where many pages are being removed.
** It is necessary to scan the entire hash table */
iStop = 0;
h = pCache->nHash - 1;
}
for(;;){
PgHdr1 **pp;
PgHdr1 *pPage;
assert( h<pCache->nHash );
pp = &pCache->apHash[h];
while( (pPage = *pp)!=0 ){
if( pPage->iKey>=iLimit ){
pCache->nPage--;
nFree++;
*pp = pPage->pNext;
if( !pPage->isPinned ) pcache1PinPage(pPage);
pcache1FreePage(pPage);
}else{
pp = &pPage->pNext;
TESTONLY( if( nPage>=0 ) nPage++; )
}
}
if( h==iStop ) break;
h = h ? h-1 : pCache->nHash - 1;
}
assert( nPage<0 || pCache->nPage==(unsigned)nPage );
END_DEBUG_TIMER( DEBUG_TIMER_BIG_TIMEOUT ){
sqlite3_log(SQLITE_NOTICE,
"slow pcache1TruncateUnsafe() %lld "
" nFree=%d nHash=%d nPage=%d iLimit=%d iMaxKey=%d",
iDebugTimer,
nFree, pCache->nHash, pCache->nPage, iLimit, pCache->iMaxKey);
}
|
| ︙ | ︙ | |||
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** Destroy a cache allocated using pcache1Create().
*/
static void pcache1Destroy(sqlite3_pcache *p){
PCache1 *pCache = (PCache1 *)p;
PGroup *pGroup = pCache->pGroup;
assert( pCache->bPurgeable || (pCache->nMax==0 && pCache->nMin==0) );
pcache1EnterMutex(pGroup);
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** Destroy a cache allocated using pcache1Create().
*/
static void pcache1Destroy(sqlite3_pcache *p){
PCache1 *pCache = (PCache1 *)p;
PGroup *pGroup = pCache->pGroup;
assert( pCache->bPurgeable || (pCache->nMax==0 && pCache->nMin==0) );
pcache1EnterMutex(pGroup);
if( pCache->nPage ) pcache1TruncateUnsafe(pCache, 0);
assert( pGroup->nMaxPage >= pCache->nMax );
pGroup->nMaxPage -= pCache->nMax;
assert( pGroup->nMinPage >= pCache->nMin );
pGroup->nMinPage -= pCache->nMin;
pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
pcache1EnforceMaxPage(pGroup);
pcache1LeaveMutex(pGroup);
|
| ︙ | ︙ |