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Overview
Comment: | Add the new sqlite3PagerUnrefPageOne() pager method to deal with the special case of unreferencing page1. |
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Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA3-256: |
b2e2100cf766da1cb499aec0ca0a9969 |
User & Date: | drh 2017-09-01 14:50:19.167 |
Context
2017-09-04
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00:19 | Fix recent test cases in test/indexepxr2.test so that they work even without SQLITE_ENABLE_STAT4 and SQLITE_ENABLE_JSON1. (check-in: 03f3cc03aa user: drh tags: trunk) | |
2017-09-01
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14:50 | Add the new sqlite3PagerUnrefPageOne() pager method to deal with the special case of unreferencing page1. (check-in: b2e2100cf7 user: drh tags: trunk) | |
12:57 | Remove an obsolete optimization in pcache that due to more recent changes was recently making the code a little slower. (check-in: c4e7e175ee user: drh tags: trunk) | |
Changes
Changes to src/btree.c.
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435 436 437 438 439 440 441 | pLock->eLock = READ_LOCK; } } } #endif /* SQLITE_OMIT_SHARED_CACHE */ | | > | 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 | pLock->eLock = READ_LOCK; } } } #endif /* SQLITE_OMIT_SHARED_CACHE */ static void releasePage(MemPage *pPage); /* Forward reference */ static void releasePageOne(MemPage *pPage); /* Forward reference */ static void releasePageNotNull(MemPage *pPage); /* Forward reference */ /* ***** This routine is used inside of assert() only **** ** ** Verify that the cursor holds the mutex on its BtShared */ |
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2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 | assert( pgno!=0 || rc==SQLITE_CORRUPT ); return rc; } /* ** Release a MemPage. This should be called once for each prior ** call to btreeGetPage. */ static void releasePageNotNull(MemPage *pPage){ assert( pPage->aData ); assert( pPage->pBt ); assert( pPage->pDbPage!=0 ); assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage ); assert( sqlite3PagerGetData(pPage->pDbPage)==pPage->aData ); assert( sqlite3_mutex_held(pPage->pBt->mutex) ); sqlite3PagerUnrefNotNull(pPage->pDbPage); } static void releasePage(MemPage *pPage){ if( pPage ) releasePageNotNull(pPage); } /* ** Get an unused page. ** ** This works just like btreeGetPage() with the addition: ** | > > > > > > > > > > > > | 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 | assert( pgno!=0 || rc==SQLITE_CORRUPT ); return rc; } /* ** Release a MemPage. This should be called once for each prior ** call to btreeGetPage. ** ** Page1 is a special case and must be released using releasePageOne(). */ static void releasePageNotNull(MemPage *pPage){ assert( pPage->aData ); assert( pPage->pBt ); assert( pPage->pDbPage!=0 ); assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage ); assert( sqlite3PagerGetData(pPage->pDbPage)==pPage->aData ); assert( sqlite3_mutex_held(pPage->pBt->mutex) ); sqlite3PagerUnrefNotNull(pPage->pDbPage); } static void releasePage(MemPage *pPage){ if( pPage ) releasePageNotNull(pPage); } static void releasePageOne(MemPage *pPage){ assert( pPage!=0 ); assert( pPage->aData ); assert( pPage->pBt ); assert( pPage->pDbPage!=0 ); assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage ); assert( sqlite3PagerGetData(pPage->pDbPage)==pPage->aData ); assert( sqlite3_mutex_held(pPage->pBt->mutex) ); sqlite3PagerUnrefPageOne(pPage->pDbPage); } /* ** Get an unused page. ** ** This works just like btreeGetPage() with the addition: ** |
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2996 2997 2998 2999 3000 3001 3002 | int isOpen = 0; rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen); if( rc!=SQLITE_OK ){ goto page1_init_failed; }else{ setDefaultSyncFlag(pBt, SQLITE_DEFAULT_WAL_SYNCHRONOUS+1); if( isOpen==0 ){ | | | 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 | int isOpen = 0; rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen); if( rc!=SQLITE_OK ){ goto page1_init_failed; }else{ setDefaultSyncFlag(pBt, SQLITE_DEFAULT_WAL_SYNCHRONOUS+1); if( isOpen==0 ){ releasePageOne(pPage1); return SQLITE_OK; } } rc = SQLITE_NOTADB; }else{ setDefaultSyncFlag(pBt, SQLITE_DEFAULT_SYNCHRONOUS+1); } |
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3043 3044 3045 3046 3047 3048 3049 | if( (u32)pageSize!=pBt->pageSize ){ /* After reading the first page of the database assuming a page size ** of BtShared.pageSize, we have discovered that the page-size is ** actually pageSize. Unlock the database, leave pBt->pPage1 at ** zero and return SQLITE_OK. The caller will call this function ** again with the correct page-size. */ | | | 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 | if( (u32)pageSize!=pBt->pageSize ){ /* After reading the first page of the database assuming a page size ** of BtShared.pageSize, we have discovered that the page-size is ** actually pageSize. Unlock the database, leave pBt->pPage1 at ** zero and return SQLITE_OK. The caller will call this function ** again with the correct page-size. */ releasePageOne(pPage1); pBt->usableSize = usableSize; pBt->pageSize = pageSize; freeTempSpace(pBt); rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, pageSize-usableSize); return rc; } |
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3097 3098 3099 3100 3101 3102 3103 | } assert( pBt->maxLeaf + 23 <= MX_CELL_SIZE(pBt) ); pBt->pPage1 = pPage1; pBt->nPage = nPage; return SQLITE_OK; page1_init_failed: | | | 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 | } assert( pBt->maxLeaf + 23 <= MX_CELL_SIZE(pBt) ); pBt->pPage1 = pPage1; pBt->nPage = nPage; return SQLITE_OK; page1_init_failed: releasePageOne(pPage1); pBt->pPage1 = 0; return rc; } #ifndef NDEBUG /* ** Return the number of cursors open on pBt. This is for use |
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3142 3143 3144 3145 3146 3147 3148 | assert( sqlite3_mutex_held(pBt->mutex) ); assert( countValidCursors(pBt,0)==0 || pBt->inTransaction>TRANS_NONE ); if( pBt->inTransaction==TRANS_NONE && pBt->pPage1!=0 ){ MemPage *pPage1 = pBt->pPage1; assert( pPage1->aData ); assert( sqlite3PagerRefcount(pBt->pPager)==1 ); pBt->pPage1 = 0; | | | 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 | assert( sqlite3_mutex_held(pBt->mutex) ); assert( countValidCursors(pBt,0)==0 || pBt->inTransaction>TRANS_NONE ); if( pBt->inTransaction==TRANS_NONE && pBt->pPage1!=0 ){ MemPage *pPage1 = pBt->pPage1; assert( pPage1->aData ); assert( sqlite3PagerRefcount(pBt->pPager)==1 ); pBt->pPage1 = 0; releasePageOne(pPage1); } } /* ** If pBt points to an empty file then convert that empty file ** into a new empty database by initializing the first page of ** the database. |
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4064 4065 4066 4067 4068 4069 4070 | ** sure pPage1->aData is set correctly. */ if( btreeGetPage(pBt, 1, &pPage1, 0)==SQLITE_OK ){ int nPage = get4byte(28+(u8*)pPage1->aData); testcase( nPage==0 ); if( nPage==0 ) sqlite3PagerPagecount(pBt->pPager, &nPage); testcase( pBt->nPage!=nPage ); pBt->nPage = nPage; | | | 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091 | ** sure pPage1->aData is set correctly. */ if( btreeGetPage(pBt, 1, &pPage1, 0)==SQLITE_OK ){ int nPage = get4byte(28+(u8*)pPage1->aData); testcase( nPage==0 ); if( nPage==0 ) sqlite3PagerPagecount(pBt->pPager, &nPage); testcase( pBt->nPage!=nPage ); pBt->nPage = nPage; releasePageOne(pPage1); } assert( countValidCursors(pBt, 1)==0 ); pBt->inTransaction = TRANS_READ; btreeClearHasContent(pBt); } btreeEndTransaction(p); |
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Changes to src/pager.c.
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5346 5347 5348 5349 5350 5351 5352 | ** transaction and unlock the pager. ** ** Except, in locking_mode=EXCLUSIVE when there is nothing to in ** the rollback journal, the unlock is not performed and there is ** nothing to rollback, so this routine is a no-op. */ static void pagerUnlockIfUnused(Pager *pPager){ | | > | 5346 5347 5348 5349 5350 5351 5352 5353 5354 5355 5356 5357 5358 5359 5360 5361 | ** transaction and unlock the pager. ** ** Except, in locking_mode=EXCLUSIVE when there is nothing to in ** the rollback journal, the unlock is not performed and there is ** nothing to rollback, so this routine is a no-op. */ static void pagerUnlockIfUnused(Pager *pPager){ if( sqlite3PcacheRefCount(pPager->pPCache)==0 ){ assert( pPager->nMmapOut==0 ); /* because page1 is never memory mapped */ pagerUnlockAndRollback(pPager); } } /* ** The page getter methods each try to acquire a reference to a ** page with page number pgno. If the requested reference is |
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5632 5633 5634 5635 5636 5637 5638 | if( pPage==0 ) return 0; return sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pPage); } /* ** Release a page reference. ** | | < | > > | > > > | < > > | > > > > > > > > > | 5633 5634 5635 5636 5637 5638 5639 5640 5641 5642 5643 5644 5645 5646 5647 5648 5649 5650 5651 5652 5653 5654 5655 5656 5657 5658 5659 5660 5661 5662 5663 5664 5665 5666 5667 5668 5669 5670 5671 5672 5673 5674 5675 5676 5677 5678 | if( pPage==0 ) return 0; return sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pPage); } /* ** Release a page reference. ** ** The sqlite3PagerUnref() and sqlite3PagerUnrefNotNull() may only be ** used if we know that the page being released is not the last page. ** The btree layer always holds page1 open until the end, so these first ** to routines can be used to release any page other than BtShared.pPage1. ** ** Use sqlite3PagerUnrefPageOne() to release page1. This latter routine ** checks the total number of outstanding pages and if the number of ** pages reaches zero it drops the database lock. */ void sqlite3PagerUnrefNotNull(DbPage *pPg){ TESTONLY( Pager *pPager = pPg->pPager; ) assert( pPg!=0 ); if( pPg->flags & PGHDR_MMAP ){ assert( pPg->pgno!=1 ); /* Page1 is never memory mapped */ pagerReleaseMapPage(pPg); }else{ sqlite3PcacheRelease(pPg); } /* Do not use this routine to release the last reference to page1 */ assert( sqlite3PcacheRefCount(pPager->pPCache)>0 ); } void sqlite3PagerUnref(DbPage *pPg){ if( pPg ) sqlite3PagerUnrefNotNull(pPg); } void sqlite3PagerUnrefPageOne(DbPage *pPg){ Pager *pPager; assert( pPg!=0 ); assert( pPg->pgno==1 ); assert( (pPg->flags & PGHDR_MMAP)==0 ); /* Page1 is never memory mapped */ pPager = pPg->pPager; sqlite3PcacheRelease(pPg); pagerUnlockIfUnused(pPager); } /* ** This function is called at the start of every write transaction. ** There must already be a RESERVED or EXCLUSIVE lock on the database ** file when this routine is called. ** |
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Changes to src/pager.h.
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147 148 149 150 151 152 153 154 155 156 157 158 159 160 | /* Functions used to obtain and release page references. */ int sqlite3PagerGet(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag); DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno); void sqlite3PagerRef(DbPage*); void sqlite3PagerUnref(DbPage*); void sqlite3PagerUnrefNotNull(DbPage*); /* Operations on page references. */ int sqlite3PagerWrite(DbPage*); void sqlite3PagerDontWrite(DbPage*); int sqlite3PagerMovepage(Pager*,DbPage*,Pgno,int); int sqlite3PagerPageRefcount(DbPage*); void *sqlite3PagerGetData(DbPage *); | > | 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 | /* Functions used to obtain and release page references. */ int sqlite3PagerGet(Pager *pPager, Pgno pgno, DbPage **ppPage, int clrFlag); DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno); void sqlite3PagerRef(DbPage*); void sqlite3PagerUnref(DbPage*); void sqlite3PagerUnrefNotNull(DbPage*); void sqlite3PagerUnrefPageOne(DbPage*); /* Operations on page references. */ int sqlite3PagerWrite(DbPage*); void sqlite3PagerDontWrite(DbPage*); int sqlite3PagerMovepage(Pager*,DbPage*,Pgno,int); int sqlite3PagerPageRefcount(DbPage*); void *sqlite3PagerGetData(DbPage *); |
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