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Overview
Comment: | Change the page cache so that a new sqlite3_pcache object is allocated as soon as the page cache is opened, not delayed until the first fetch request. This give a noticable performance boost. The interface between pager and the page cache has changed slightly, which might break ZIPVFS. |
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Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
f1f94a971e031e784f8c30a6faf829df |
User & Date: | drh 2014-08-26 15:06:49.829 |
Context
2014-08-27
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00:50 | Performance enhancement in sqlite3VdbeMemNulTerminate(). (check-in: f94cacc393 user: drh tags: trunk) | |
2014-08-26
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15:06 | Change the page cache so that a new sqlite3_pcache object is allocated as soon as the page cache is opened, not delayed until the first fetch request. This give a noticable performance boost. The interface between pager and the page cache has changed slightly, which might break ZIPVFS. (check-in: f1f94a971e user: drh tags: trunk) | |
2014-08-25
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22:37 | Add an assert() and five testcase() macros to the OP_Cast opcode implementation to help verify that it is fully tested. (check-in: af364cce9d user: drh tags: trunk) | |
Changes
Changes to src/pager.c.
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3618 3619 3620 3621 3622 3623 3624 | if( rc==SQLITE_OK ){ pager_reset(pPager); pPager->dbSize = (Pgno)((nByte+pageSize-1)/pageSize); pPager->pageSize = pageSize; sqlite3PageFree(pPager->pTmpSpace); pPager->pTmpSpace = pNew; | | | 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 | if( rc==SQLITE_OK ){ pager_reset(pPager); pPager->dbSize = (Pgno)((nByte+pageSize-1)/pageSize); pPager->pageSize = pageSize; sqlite3PageFree(pPager->pTmpSpace); pPager->pTmpSpace = pNew; rc = sqlite3PcacheSetPageSize(pPager->pPCache, pageSize); } } *pPageSize = pPager->pageSize; if( rc==SQLITE_OK ){ if( nReserve<0 ) nReserve = pPager->nReserve; assert( nReserve>=0 && nReserve<1000 ); |
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4381 4382 4383 4384 4385 4386 4387 | ** ** The doNotSpill ROLLBACK and OFF bits inhibits all cache spilling ** regardless of whether or not a sync is required. This is set during ** a rollback or by user request, respectively. ** ** Spilling is also prohibited when in an error state since that could ** lead to database corruption. In the current implementaton it | | | 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 | ** ** The doNotSpill ROLLBACK and OFF bits inhibits all cache spilling ** regardless of whether or not a sync is required. This is set during ** a rollback or by user request, respectively. ** ** 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==3 ** 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. */ if( NEVER(pPager->errCode) ) return SQLITE_OK; testcase( pPager->doNotSpill & SPILLFLAG_ROLLBACK ); testcase( pPager->doNotSpill & SPILLFLAG_OFF ); |
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4717 4718 4719 4720 4721 4722 4723 | */ if( rc==SQLITE_OK ){ assert( pPager->memDb==0 ); rc = sqlite3PagerSetPagesize(pPager, &szPageDflt, -1); testcase( rc!=SQLITE_OK ); } | > > > > > > > | | < > < < < < < < | 4717 4718 4719 4720 4721 4722 4723 4724 4725 4726 4727 4728 4729 4730 4731 4732 4733 4734 4735 4736 4737 4738 4739 4740 4741 4742 4743 4744 4745 4746 4747 | */ if( rc==SQLITE_OK ){ assert( pPager->memDb==0 ); rc = sqlite3PagerSetPagesize(pPager, &szPageDflt, -1); testcase( rc!=SQLITE_OK ); } /* Initialize the PCache object. */ if( rc==SQLITE_OK ){ assert( nExtra<1000 ); nExtra = ROUND8(nExtra); rc = sqlite3PcacheOpen(szPageDflt, nExtra, !memDb, !memDb?pagerStress:0, (void *)pPager, pPager->pPCache); } /* If an error occurred above, free the Pager structure and close the file. */ if( rc!=SQLITE_OK ){ sqlite3OsClose(pPager->fd); sqlite3PageFree(pPager->pTmpSpace); sqlite3_free(pPager); return rc; } PAGERTRACE(("OPEN %d %s\n", FILEHANDLEID(pPager->fd), pPager->zFilename)); IOTRACE(("OPEN %p %s\n", pPager, pPager->zFilename)) pPager->useJournal = (u8)useJournal; /* pPager->stmtOpen = 0; */ /* pPager->stmtInUse = 0; */ /* pPager->nRef = 0; */ |
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5314 5315 5316 5317 5318 5319 5320 | } } if( rc!=SQLITE_OK ){ goto pager_acquire_err; } } | | | 5315 5316 5317 5318 5319 5320 5321 5322 5323 5324 5325 5326 5327 5328 5329 | } } if( rc!=SQLITE_OK ){ goto pager_acquire_err; } } rc = sqlite3PcacheFetch(pPager->pPCache, pgno, 3, ppPage); } if( rc!=SQLITE_OK ){ /* Either the call to sqlite3PcacheFetch() returned an error or the ** pager was already in the error-state when this function was called. ** Set pPg to 0 and jump to the exception handler. */ pPg = 0; |
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Changes to src/pcache.c.
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139 140 141 142 143 144 145 146 147 148 149 150 151 152 | if( p->pCache->bPurgeable ){ if( p->pgno==1 ){ p->pCache->pPage1 = 0; } sqlite3GlobalConfig.pcache2.xUnpin(p->pCache->pCache, p->pPage, 0); } } /*************************************************** General Interfaces ****** ** ** Initialize and shutdown the page cache subsystem. Neither of these ** functions are threadsafe. */ int sqlite3PcacheInitialize(void){ | > > > > > > > > > > > | 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 | if( p->pCache->bPurgeable ){ if( p->pgno==1 ){ p->pCache->pPage1 = 0; } sqlite3GlobalConfig.pcache2.xUnpin(p->pCache->pCache, p->pPage, 0); } } /* ** Compute the number of pages of cache requested. */ static int numberOfCachePages(PCache *p){ if( p->szCache>=0 ){ return p->szCache; }else{ return (int)((-1024*(i64)p->szCache)/(p->szPage+p->szExtra)); } } /*************************************************** General Interfaces ****** ** ** Initialize and shutdown the page cache subsystem. Neither of these ** functions are threadsafe. */ int sqlite3PcacheInitialize(void){ |
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172 173 174 175 176 177 178 | /* ** Create a new PCache object. Storage space to hold the object ** has already been allocated and is passed in as the p pointer. ** The caller discovers how much space needs to be allocated by ** calling sqlite3PcacheSize(). */ | | | > | > > > > > > > | | > | < | | < < < < < < | < < < > | < < < < < < < < < < < < < < < < < < < | > > | | 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 | /* ** Create a new PCache object. Storage space to hold the object ** has already been allocated and is passed in as the p pointer. ** The caller discovers how much space needs to be allocated by ** calling sqlite3PcacheSize(). */ int sqlite3PcacheOpen( int szPage, /* Size of every page */ int szExtra, /* Extra space associated with each page */ int bPurgeable, /* True if pages are on backing store */ int (*xStress)(void*,PgHdr*),/* Call to try to make pages clean */ void *pStress, /* Argument to xStress */ PCache *p /* Preallocated space for the PCache */ ){ memset(p, 0, sizeof(PCache)); p->szPage = 1; p->szExtra = szExtra; p->bPurgeable = bPurgeable; p->eCreate = 2; p->xStress = xStress; p->pStress = pStress; p->szCache = 100; return sqlite3PcacheSetPageSize(p, szPage); } /* ** Change the page size for PCache object. The caller must ensure that there ** are no outstanding page references when this function is called. */ int sqlite3PcacheSetPageSize(PCache *pCache, int szPage){ assert( pCache->nRef==0 && pCache->pDirty==0 ); if( pCache->szPage ){ sqlite3_pcache *pNew; pNew = sqlite3GlobalConfig.pcache2.xCreate( szPage, pCache->szExtra + sizeof(PgHdr), pCache->bPurgeable ); if( pNew==0 ) return SQLITE_NOMEM; sqlite3GlobalConfig.pcache2.xCachesize(pNew, numberOfCachePages(pCache)); if( pCache->pCache ){ sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache); } pCache->pCache = pNew; pCache->pPage1 = 0; pCache->szPage = szPage; } return SQLITE_OK; } /* ** Try to obtain a page from the cache. */ int sqlite3PcacheFetch( PCache *pCache, /* Obtain the page from this cache */ Pgno pgno, /* Page number to obtain */ int createFlag, /* If true, create page if it does not exist already */ PgHdr **ppPage /* Write the page here */ ){ sqlite3_pcache_page *pPage; PgHdr *pPgHdr = 0; int eCreate; assert( pCache!=0 ); assert( pCache->pCache!=0 ); assert( createFlag==3 || createFlag==0 ); assert( pgno>0 ); /* eCreate defines what to do if the page does not exist. ** 0 Do not allocate a new page. (createFlag==0) ** 1 Allocate a new page if doing so is inexpensive. ** (createFlag==1 AND bPurgeable AND pDirty) ** 2 Allocate a new page even it doing so is difficult. ** (createFlag==1 AND !(bPurgeable AND pDirty) */ eCreate = createFlag & pCache->eCreate; assert( eCreate==0 || eCreate==1 || eCreate==2 ); assert( createFlag==0 || pCache->eCreate==eCreate ); assert( createFlag==0 || eCreate==1+(!pCache->bPurgeable||!pCache->pDirty) ); pPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate); if( !pPage && eCreate==1 ){ PgHdr *pPg; /* Find a dirty page to write-out and recycle. First try to find a ** page that does not require a journal-sync (one with PGHDR_NEED_SYNC ** cleared), but if that is not possible settle for any other |
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467 468 469 470 471 472 473 | } } /* ** Close a cache. */ void sqlite3PcacheClose(PCache *pCache){ | | | < | 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 | } } /* ** Close a cache. */ void sqlite3PcacheClose(PCache *pCache){ assert( pCache->pCache!=0 ); sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache); } /* ** Discard the contents of the cache. */ void sqlite3PcacheClear(PCache *pCache){ sqlite3PcacheTruncate(pCache, 0); |
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578 579 580 581 582 583 584 | return p->nRef; } /* ** Return the total number of pages in the cache. */ int sqlite3PcachePagecount(PCache *pCache){ | < | | < < > < | | < | | < | 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 | return p->nRef; } /* ** Return the total number of pages in the cache. */ int sqlite3PcachePagecount(PCache *pCache){ assert( pCache->pCache!=0 ); return sqlite3GlobalConfig.pcache2.xPagecount(pCache->pCache); } #ifdef SQLITE_TEST /* ** Get the suggested cache-size value. */ int sqlite3PcacheGetCachesize(PCache *pCache){ return numberOfCachePages(pCache); } #endif /* ** Set the suggested cache-size value. */ void sqlite3PcacheSetCachesize(PCache *pCache, int mxPage){ assert( pCache->pCache!=0 ); pCache->szCache = mxPage; sqlite3GlobalConfig.pcache2.xCachesize(pCache->pCache, numberOfCachePages(pCache)); } /* ** Free up as much memory as possible from the page cache. */ void sqlite3PcacheShrink(PCache *pCache){ assert( pCache->pCache!=0 ); sqlite3GlobalConfig.pcache2.xShrink(pCache->pCache); } #if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG) /* ** For all dirty pages currently in the cache, invoke the specified ** callback. This is only used if the SQLITE_CHECK_PAGES macro is ** defined. |
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Changes to src/pcache.h.
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64 65 66 67 68 69 70 | */ void sqlite3PCacheBufferSetup(void *, int sz, int n); /* Create a new pager cache. ** Under memory stress, invoke xStress to try to make pages clean. ** Only clean and unpinned pages can be reclaimed. */ | | | | 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 | */ void sqlite3PCacheBufferSetup(void *, int sz, int n); /* Create a new pager cache. ** Under memory stress, invoke xStress to try to make pages clean. ** Only clean and unpinned pages can be reclaimed. */ int sqlite3PcacheOpen( int szPage, /* Size of every page */ int szExtra, /* Extra space associated with each page */ int bPurgeable, /* True if pages are on backing store */ int (*xStress)(void*, PgHdr*), /* Call to try to make pages clean */ void *pStress, /* Argument to xStress */ PCache *pToInit /* Preallocated space for the PCache */ ); /* Modify the page-size after the cache has been created. */ int sqlite3PcacheSetPageSize(PCache *, int); /* Return the size in bytes of a PCache object. Used to preallocate ** storage space. */ int sqlite3PcacheSize(void); /* One release per successful fetch. Page is pinned until released. |
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