From: drh Date: Fri, 1 Sep 2017 14:50:19 +0000 (+0000) Subject: Add the new sqlite3PagerUnrefPageOne() pager method to deal with the special X-Git-Tag: version-3.21.0~110 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3908fe90b1e9b0c146d6548f5c100613f88dc9d5;p=thirdparty%2Fsqlite.git Add the new sqlite3PagerUnrefPageOne() pager method to deal with the special case of unreferencing page1. FossilOrigin-Name: b2e2100cf766da1cb499aec0ca0a9969d7af5d93312ab8cf895fbf4a6ffb9b2f --- diff --git a/manifest b/manifest index 082580d908..633c8bc712 100644 --- a/manifest +++ b/manifest @@ -1,5 +1,5 @@ -C Remove\san\sobsolete\soptimization\sin\spcache\sthat\sdue\sto\smore\srecent\schanges\nwas\srecently\smaking\sthe\scode\sa\slittle\sslower. -D 2017-09-01T12:57:33.041 +C Add\sthe\snew\ssqlite3PagerUnrefPageOne()\spager\smethod\sto\sdeal\swith\sthe\sspecial\ncase\sof\sunreferencing\spage1. +D 2017-09-01T14:50:19.167 F Makefile.in c644bbe8ebe4aae82ad6783eae6b6beea4c727b99ff97568b847ced5e2ac7afb F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434 F Makefile.msc 25b154da7f0b3d4924f27378c1f8d006285b80811f1ccf3ed953dbebf6282136 @@ -399,7 +399,7 @@ F src/auth.c 6277d63837357549fe14e723490d6dc1a38768d71c795c5eb5c0f8a99f918f73 F src/backup.c faf17e60b43233c214aae6a8179d24503a61e83b F src/bitvec.c 17ea48eff8ba979f1f5b04cc484c7bb2be632f33 F src/btmutex.c 0e9ce2d56159b89b9bc8e197e023ee11e39ff8ca -F src/btree.c 1033b88fe50aba7d364b5a19666a9a274caa8d4c25ab7f3914221997b46af44a +F src/btree.c f1ac9509f4595d034fe432982c39d51ac2bfc9bd83136d16255aede35c526b45 F src/btree.h 32ef5d3f25dc70ef1ee9cecf84a023c21378f06a57cd701d2e866e141b150f09 F src/btreeInt.h 55b702efce17e5d1941865464227d3802cfc9c7c832fac81d4c94dced47a71fc F src/build.c e71e96a67daf3d1dd23188423e66cd6af38017e2ec73fead5d2b57da2d3c7e16 @@ -443,8 +443,8 @@ F src/os_setup.h 0dbaea40a7d36bf311613d31342e0b99e2536586 F src/os_unix.c 489aa972ccc34f7b4770b891694b32101c59ddd4be4ef0ddd9a4da58c145c1a6 F src/os_win.c 964165b66cde03abc72fe948198b01be608436894732eadb94c8720d2467f223 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a -F src/pager.c bf51378c57c8e05d7f4d7bb9861f403a2e40cde82e25513401216d1ed30bc3e5 -F src/pager.h f2a99646c5533ffe11afa43e9e0bea74054e4efa +F src/pager.c 3936b32a0a45f1b80462b38ba1ed0556e62843554a089ab9c4be1a35c97f23bc +F src/pager.h 581698f2177e8bd4008fe4760898ce20b6133d1df22139b9101b5155f900df7a F src/parse.y 52ef3cecd0934e9da4a45b585883a03243ad615d338ad94f44501a05891dcdfa F src/pcache.c 4bada070456980c3c1f16d58ec2e64e389ad77b935e3d77e0c96e7bbd397289c F src/pcache.h 072f94d29281cffd99e46c1539849f248c4b56ae7684c1f36626797fee375170 @@ -1651,7 +1651,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0 -P 919863b14859d958d6c078097faae02070c7bd082e2814cf3f84bd84921e4419 -R 0eee553fc228f3f42e4580f46005e756 +P c4e7e175eecfd79015f4fae99618dfce6baf97c21bf3c909ea535d4e12dcaaad +R 6f9a52521f107a3c330b7cfcb23523cf U drh -Z 71c472332c9be0857de95ba6da186b34 +Z f39368718f6b0d67941da00fc11a34d5 diff --git a/manifest.uuid b/manifest.uuid index e4cecf80a4..1aa72acac9 100644 --- a/manifest.uuid +++ b/manifest.uuid @@ -1 +1 @@ -c4e7e175eecfd79015f4fae99618dfce6baf97c21bf3c909ea535d4e12dcaaad \ No newline at end of file +b2e2100cf766da1cb499aec0ca0a9969d7af5d93312ab8cf895fbf4a6ffb9b2f \ No newline at end of file diff --git a/src/btree.c b/src/btree.c index 9ec61507cb..3ca0037e9d 100644 --- a/src/btree.c +++ b/src/btree.c @@ -439,7 +439,8 @@ static void downgradeAllSharedCacheTableLocks(Btree *p){ #endif /* SQLITE_OMIT_SHARED_CACHE */ -static void releasePage(MemPage *pPage); +static void releasePage(MemPage *pPage); /* Forward reference */ +static void releasePageOne(MemPage *pPage); /* Forward reference */ static void releasePageNotNull(MemPage *pPage); /* Forward reference */ /* @@ -2109,6 +2110,8 @@ getAndInitPage_error: /* ** 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 ); @@ -2122,6 +2125,16 @@ static void releasePageNotNull(MemPage *pPage){ 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. @@ -3000,7 +3013,7 @@ static int lockBtree(BtShared *pBt){ }else{ setDefaultSyncFlag(pBt, SQLITE_DEFAULT_WAL_SYNCHRONOUS+1); if( isOpen==0 ){ - releasePage(pPage1); + releasePageOne(pPage1); return SQLITE_OK; } } @@ -3047,7 +3060,7 @@ static int lockBtree(BtShared *pBt){ ** zero and return SQLITE_OK. The caller will call this function ** again with the correct page-size. */ - releasePage(pPage1); + releasePageOne(pPage1); pBt->usableSize = usableSize; pBt->pageSize = pageSize; freeTempSpace(pBt); @@ -3101,7 +3114,7 @@ static int lockBtree(BtShared *pBt){ return SQLITE_OK; page1_init_failed: - releasePage(pPage1); + releasePageOne(pPage1); pBt->pPage1 = 0; return rc; } @@ -3146,7 +3159,7 @@ static void unlockBtreeIfUnused(BtShared *pBt){ assert( pPage1->aData ); assert( sqlite3PagerRefcount(pBt->pPager)==1 ); pBt->pPage1 = 0; - releasePageNotNull(pPage1); + releasePageOne(pPage1); } } @@ -4068,7 +4081,7 @@ int sqlite3BtreeRollback(Btree *p, int tripCode, int writeOnly){ if( nPage==0 ) sqlite3PagerPagecount(pBt->pPager, &nPage); testcase( pBt->nPage!=nPage ); pBt->nPage = nPage; - releasePage(pPage1); + releasePageOne(pPage1); } assert( countValidCursors(pBt, 1)==0 ); pBt->inTransaction = TRANS_READ; diff --git a/src/pager.c b/src/pager.c index 2e5977fe43..b3ec03bd95 100644 --- a/src/pager.c +++ b/src/pager.c @@ -5350,7 +5350,8 @@ int sqlite3PagerSharedLock(Pager *pPager){ ** nothing to rollback, so this routine is a no-op. */ static void pagerUnlockIfUnused(Pager *pPager){ - if( pPager->nMmapOut==0 && (sqlite3PcacheRefCount(pPager->pPCache)==0) ){ + if( sqlite3PcacheRefCount(pPager->pPCache)==0 ){ + assert( pPager->nMmapOut==0 ); /* because page1 is never memory mapped */ pagerUnlockAndRollback(pPager); } } @@ -5636,25 +5637,39 @@ DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){ /* ** Release a page reference. ** -** If the number of references to the page drop to zero, then the -** page is added to the LRU list. When all references to all pages -** are released, a rollback occurs and the lock on the database is -** removed. +** 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){ - Pager *pPager; + TESTONLY( Pager *pPager = pPg->pPager; ) assert( pPg!=0 ); - pPager = pPg->pPager; if( pPg->flags & PGHDR_MMAP ){ + assert( pPg->pgno!=1 ); /* Page1 is never memory mapped */ pagerReleaseMapPage(pPg); }else{ sqlite3PcacheRelease(pPg); } - pagerUnlockIfUnused(pPager); + /* 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. diff --git a/src/pager.h b/src/pager.h index 585ef29497..126267bcc8 100644 --- a/src/pager.h +++ b/src/pager.h @@ -151,6 +151,7 @@ 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*);