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Overview
Comment: | Add the new PGHDR_CLEAN bit to PgHdr.flags in pcache.c. This bit is always the opposite of PGHDR_DIRTY. Use the extra bit to avoid a comparison for a small performance boost. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
8619fc346d9a5a66a3c4566b4cc032b6 |
User & Date: | drh 2015-06-29 04:21:15.041 |
Context
2015-06-29
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14:11 | Simplifications and performance improvement in pager_write(). (check-in: ab7aeeead3 user: drh tags: trunk) | |
04:21 | Add the new PGHDR_CLEAN bit to PgHdr.flags in pcache.c. This bit is always the opposite of PGHDR_DIRTY. Use the extra bit to avoid a comparison for a small performance boost. (check-in: 8619fc346d user: drh tags: trunk) | |
03:28 | Very small size reduction and performance increase in sqlite3BitvecTest(). (check-in: 9b3a7281bd user: drh tags: trunk) | |
Changes
Changes to src/pcache.c.
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324 325 326 327 328 329 330 331 332 333 334 335 336 337 | memset(pPgHdr, 0, sizeof(PgHdr)); pPgHdr->pPage = pPage; pPgHdr->pData = pPage->pBuf; pPgHdr->pExtra = (void *)&pPgHdr[1]; memset(pPgHdr->pExtra, 0, pCache->szExtra); pPgHdr->pCache = pCache; pPgHdr->pgno = pgno; return sqlite3PcacheFetchFinish(pCache,pgno,pPage); } /* ** This routine converts the sqlite3_pcache_page object returned by ** sqlite3PcacheFetch() into an initialized PgHdr object. This routine ** must be called after sqlite3PcacheFetch() in order to get a usable | > | 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 | memset(pPgHdr, 0, sizeof(PgHdr)); pPgHdr->pPage = pPage; pPgHdr->pData = pPage->pBuf; pPgHdr->pExtra = (void *)&pPgHdr[1]; memset(pPgHdr->pExtra, 0, pCache->szExtra); pPgHdr->pCache = pCache; pPgHdr->pgno = pgno; pPgHdr->flags = PGHDR_CLEAN; return sqlite3PcacheFetchFinish(pCache,pgno,pPage); } /* ** This routine converts the sqlite3_pcache_page object returned by ** sqlite3PcacheFetch() into an initialized PgHdr object. This routine ** must be called after sqlite3PcacheFetch() in order to get a usable |
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362 363 364 365 366 367 368 | ** reference count drops to 0, then it is made eligible for recycling. */ void SQLITE_NOINLINE sqlite3PcacheRelease(PgHdr *p){ assert( p->nRef>0 ); p->nRef--; if( p->nRef==0 ){ p->pCache->nRef--; | | | 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 | ** reference count drops to 0, then it is made eligible for recycling. */ void SQLITE_NOINLINE sqlite3PcacheRelease(PgHdr *p){ assert( p->nRef>0 ); p->nRef--; if( p->nRef==0 ){ p->pCache->nRef--; if( p->flags&PGHDR_CLEAN ){ pcacheUnpin(p); }else if( p->pDirtyPrev!=0 ){ /* Move the page to the head of the dirty list. */ pcacheManageDirtyList(p, PCACHE_DIRTYLIST_FRONT); } } } |
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398 399 400 401 402 403 404 | } /* ** Make sure the page is marked as dirty. If it isn't dirty already, ** make it so. */ void sqlite3PcacheMakeDirty(PgHdr *p){ | < > > | | > | > > > | 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 | } /* ** Make sure the page is marked as dirty. If it isn't dirty already, ** make it so. */ void sqlite3PcacheMakeDirty(PgHdr *p){ assert( p->nRef>0 ); if( p->flags & (PGHDR_CLEAN|PGHDR_DONT_WRITE) ){ p->flags &= ~PGHDR_DONT_WRITE; if( p->flags & PGHDR_CLEAN ){ p->flags ^= (PGHDR_DIRTY|PGHDR_CLEAN); assert( (p->flags & (PGHDR_DIRTY|PGHDR_CLEAN))==PGHDR_DIRTY ); pcacheManageDirtyList(p, PCACHE_DIRTYLIST_ADD); } } } /* ** Make sure the page is marked as clean. If it isn't clean already, ** make it so. */ void sqlite3PcacheMakeClean(PgHdr *p){ if( (p->flags & PGHDR_DIRTY) ){ assert( (p->flags & PGHDR_CLEAN)==0 ); pcacheManageDirtyList(p, PCACHE_DIRTYLIST_REMOVE); p->flags &= ~(PGHDR_DIRTY|PGHDR_NEED_SYNC); p->flags |= PGHDR_CLEAN; if( p->nRef==0 ){ pcacheUnpin(p); } } } /* |
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Changes to src/pcache.h.
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42 43 44 45 46 47 48 49 50 51 52 53 54 55 | PCache *pCache; /* Cache that owns this page */ PgHdr *pDirtyNext; /* Next element in list of dirty pages */ PgHdr *pDirtyPrev; /* Previous element in list of dirty pages */ }; /* Bit values for PgHdr.flags */ #define PGHDR_DIRTY 0x002 /* Page has changed */ #define PGHDR_NEED_SYNC 0x004 /* Fsync the rollback journal before ** writing this page to the database */ #define PGHDR_NEED_READ 0x008 /* Content is unread */ #define PGHDR_REUSE_UNLIKELY 0x010 /* A hint that reuse is unlikely */ #define PGHDR_DONT_WRITE 0x020 /* Do not write content to disk */ | > | 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | PCache *pCache; /* Cache that owns this page */ PgHdr *pDirtyNext; /* Next element in list of dirty pages */ PgHdr *pDirtyPrev; /* Previous element in list of dirty pages */ }; /* Bit values for PgHdr.flags */ #define PGHDR_CLEAN 0x001 /* Page is unchanged */ #define PGHDR_DIRTY 0x002 /* Page has changed */ #define PGHDR_NEED_SYNC 0x004 /* Fsync the rollback journal before ** writing this page to the database */ #define PGHDR_NEED_READ 0x008 /* Content is unread */ #define PGHDR_REUSE_UNLIKELY 0x010 /* A hint that reuse is unlikely */ #define PGHDR_DONT_WRITE 0x020 /* Do not write content to disk */ |
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