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Overview
Comment: | Enhance sqlite3PcacheTruncate() to run faster in the common case where the cutoff is just a few pages less than the page number highwater mark. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | branch-3.14 |
Files: | files | file ages | folders |
SHA1: |
03dceaea15aa357097a4615ef6044be3 |
User & Date: | drh 2016-08-11 13:03:51.493 |
Context
2016-08-11
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13:08 | Increase the version number to 3.14.1. (check-in: 34aed3a318 user: drh tags: branch-3.14) | |
13:03 | Enhance sqlite3PcacheTruncate() to run faster in the common case where the cutoff is just a few pages less than the page number highwater mark. (check-in: 03dceaea15 user: drh tags: branch-3.14) | |
2016-08-10
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15:02 | Tweaks to pcache1TruncateUnsafe() to make it slightly smaller and faster and easier to test. (check-in: 059f4e2efe user: drh tags: trunk) | |
11:50 | Fix pcache1TruncateUnsafe() run faster for the case where iLimit is very close to iMaxKey. (check-in: b07a26df06 user: drh tags: trunk) | |
2016-08-08
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13:40 | Version 3.14 (check-in: d5e9805702 user: drh tags: trunk, release, version-3.14.0) | |
Changes
Changes to src/pcache1.c.
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628 629 630 631 632 633 634 | ** ** 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 */ ){ | | | > > > > > > > > > > > > > | > > > | > > | > > | | 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 | ** ** 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; assert( sqlite3_mutex_held(pCache->pGroup->mutex) ); assert( pCache->iMaxKey >= iLimit ); assert( pCache->nHash > 0 ); if( pCache->iMaxKey - iLimit < pCache->nHash ){ /* 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. */ h = iLimit % pCache->nHash; iStop = 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 */ h = pCache->nHash/2; iStop = h - 1; } for(;;){ PgHdr1 **pp; PgHdr1 *pPage; assert( h<pCache->nHash ); pp = &pCache->apHash[h]; while( (pPage = *pp)!=0 ){ if( pPage->iKey>=iLimit ){ pCache->nPage--; *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+1) % pCache->nHash; } assert( nPage<0 || pCache->nPage==(unsigned)nPage ); } /******************************************************************************/ /******** sqlite3_pcache Methods **********************************************/ /* ** Implementation of the sqlite3_pcache.xInit method. |
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1123 1124 1125 1126 1127 1128 1129 | ** 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); | | | 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 | ** 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(pCache); pcache1LeaveMutex(pGroup); |
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