From 14e845a9d42cb5e02cad6731fee6c5e57cbea91f Mon Sep 17 00:00:00 2001 From: drh Date: Thu, 25 May 2017 21:35:56 +0000 Subject: [PATCH] Small performance increase and size decrease in the btreeInitPage() routine. FossilOrigin-Name: 6f415833e0554706dcf04f68ecba4ca2e54c08f3bbf6a1dba182bb132c912a2e --- manifest | 12 +-- manifest.uuid | 2 +- src/btree.c | 227 +++++++++++++++++++++++++------------------------- 3 files changed, 119 insertions(+), 122 deletions(-) diff --git a/manifest b/manifest index 2b231d7f0c..f6c4969a9b 100644 --- a/manifest +++ b/manifest @@ -1,5 +1,5 @@ -C Merge\sthe\sLEFT\sJOIN\squery\sflattener\sfixes\sfrom\s3.19.2. -D 2017-05-25T17:27:52.435 +C Small\sperformance\sincrease\sand\ssize\sdecrease\sin\sthe\sbtreeInitPage()\sroutine. +D 2017-05-25T21:35:56.813 F Makefile.in 1cc758ce3374a32425e4d130c2fe7b026b20de5b8843243de75f087c0a2661fb F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434 F Makefile.msc 8eeb80162074004e906b53d7340a12a14c471a83743aab975947e95ce061efcc @@ -347,7 +347,7 @@ F src/auth.c 79f96c6f33bf0e5da8d1c282cee5ebb1852bb8a6ccca3e485d7c459b035d9c3c F src/backup.c faf17e60b43233c214aae6a8179d24503a61e83b F src/bitvec.c 17ea48eff8ba979f1f5b04cc484c7bb2be632f33 F src/btmutex.c 0e9ce2d56159b89b9bc8e197e023ee11e39ff8ca -F src/btree.c 8c1fd4cfa2b0bf021386e0a1f4e30b64eea7a2c1bc2e0c3e5901a626b1ab6aa9 +F src/btree.c 0065e4bb6dc1431bca7aa806dc5635885aa93f3056bb26a4b6cc0cc53a5131f3 F src/btree.h 80f518c0788be6cec8d9f8e13bd8e380df299d2b5e4ac340dc887b0642647cfc F src/btreeInt.h a392d353104b4add58b4a59cb185f5d5693dde832c565b77d8d4c343ed98f610 F src/build.c 4026a9c554b233e50c5e9ad46963e676cf54dd2306d952aa1eaa07a1bc9ce14f @@ -1581,7 +1581,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0 -P 77fc23013cebc7797985864b91d78db5d0e2469511732044ebfaf02b891c979a edb4e819b0c058c7d74d27ebd14cc5ceb2bad6a6144a486a970182b7afe3f8b9 -R 48e976f275e28e838432234ac55ec7a3 +P 6513e4a121e32df7e5cd95f47cdf8049b85bdbcb378cf23db29838fb1143d3ce +R 9e082c4766b6279c798cfde2a46bb457 U drh -Z 8a4512e2e2f5f71bea9b11746a7f953a +Z d87e792c8c154c6048ea55d079b4cb9c diff --git a/manifest.uuid b/manifest.uuid index 34497a834f..8237c98750 100644 --- a/manifest.uuid +++ b/manifest.uuid @@ -1 +1 @@ -6513e4a121e32df7e5cd95f47cdf8049b85bdbcb378cf23db29838fb1143d3ce \ No newline at end of file +6f415833e0554706dcf04f68ecba4ca2e54c08f3bbf6a1dba182bb132c912a2e \ No newline at end of file diff --git a/src/btree.c b/src/btree.c index e5edf44c4d..8e7bfa5531 100644 --- a/src/btree.c +++ b/src/btree.c @@ -1781,6 +1781,16 @@ static int decodeFlags(MemPage *pPage, int flagByte){ ** we failed to detect any corruption. */ static int btreeInitPage(MemPage *pPage){ + int pc; /* Address of a freeblock within pPage->aData[] */ + u8 hdr; /* Offset to beginning of page header */ + u8 *data; /* Equal to pPage->aData */ + BtShared *pBt; /* The main btree structure */ + int usableSize; /* Amount of usable space on each page */ + u16 cellOffset; /* Offset from start of page to first cell pointer */ + int nFree; /* Number of unused bytes on the page */ + int top; /* First byte of the cell content area */ + int iCellFirst; /* First allowable cell or freeblock offset */ + int iCellLast; /* Last possible cell or freeblock offset */ assert( pPage->pBt!=0 ); assert( pPage->pBt->db!=0 ); @@ -1788,127 +1798,114 @@ static int btreeInitPage(MemPage *pPage){ assert( pPage->pgno==sqlite3PagerPagenumber(pPage->pDbPage) ); assert( pPage == sqlite3PagerGetExtra(pPage->pDbPage) ); assert( pPage->aData == sqlite3PagerGetData(pPage->pDbPage) ); + assert( pPage->isInit==0 ); - if( !pPage->isInit ){ - int pc; /* Address of a freeblock within pPage->aData[] */ - u8 hdr; /* Offset to beginning of page header */ - u8 *data; /* Equal to pPage->aData */ - BtShared *pBt; /* The main btree structure */ - int usableSize; /* Amount of usable space on each page */ - u16 cellOffset; /* Offset from start of page to first cell pointer */ - int nFree; /* Number of unused bytes on the page */ - int top; /* First byte of the cell content area */ - int iCellFirst; /* First allowable cell or freeblock offset */ - int iCellLast; /* Last possible cell or freeblock offset */ - - pBt = pPage->pBt; - - hdr = pPage->hdrOffset; - data = pPage->aData; - /* EVIDENCE-OF: R-28594-02890 The one-byte flag at offset 0 indicating - ** the b-tree page type. */ - if( decodeFlags(pPage, data[hdr]) ) return SQLITE_CORRUPT_BKPT; - assert( pBt->pageSize>=512 && pBt->pageSize<=65536 ); - pPage->maskPage = (u16)(pBt->pageSize - 1); - pPage->nOverflow = 0; - usableSize = pBt->usableSize; - pPage->cellOffset = cellOffset = hdr + 8 + pPage->childPtrSize; - pPage->aDataEnd = &data[usableSize]; - pPage->aCellIdx = &data[cellOffset]; - pPage->aDataOfst = &data[pPage->childPtrSize]; - /* EVIDENCE-OF: R-58015-48175 The two-byte integer at offset 5 designates - ** the start of the cell content area. A zero value for this integer is - ** interpreted as 65536. */ - top = get2byteNotZero(&data[hdr+5]); - /* EVIDENCE-OF: R-37002-32774 The two-byte integer at offset 3 gives the - ** number of cells on the page. */ - pPage->nCell = get2byte(&data[hdr+3]); - if( pPage->nCell>MX_CELL(pBt) ){ - /* To many cells for a single page. The page must be corrupt */ - return SQLITE_CORRUPT_BKPT; - } - testcase( pPage->nCell==MX_CELL(pBt) ); - /* EVIDENCE-OF: R-24089-57979 If a page contains no cells (which is only - ** possible for a root page of a table that contains no rows) then the - ** offset to the cell content area will equal the page size minus the - ** bytes of reserved space. */ - assert( pPage->nCell>0 || top==usableSize || CORRUPT_DB ); + pBt = pPage->pBt; + hdr = pPage->hdrOffset; + data = pPage->aData; + /* EVIDENCE-OF: R-28594-02890 The one-byte flag at offset 0 indicating + ** the b-tree page type. */ + if( decodeFlags(pPage, data[hdr]) ) return SQLITE_CORRUPT_BKPT; + assert( pBt->pageSize>=512 && pBt->pageSize<=65536 ); + pPage->maskPage = (u16)(pBt->pageSize - 1); + pPage->nOverflow = 0; + usableSize = pBt->usableSize; + pPage->cellOffset = cellOffset = hdr + 8 + pPage->childPtrSize; + pPage->aDataEnd = &data[usableSize]; + pPage->aCellIdx = &data[cellOffset]; + pPage->aDataOfst = &data[pPage->childPtrSize]; + /* EVIDENCE-OF: R-58015-48175 The two-byte integer at offset 5 designates + ** the start of the cell content area. A zero value for this integer is + ** interpreted as 65536. */ + top = get2byteNotZero(&data[hdr+5]); + /* EVIDENCE-OF: R-37002-32774 The two-byte integer at offset 3 gives the + ** number of cells on the page. */ + pPage->nCell = get2byte(&data[hdr+3]); + if( pPage->nCell>MX_CELL(pBt) ){ + /* To many cells for a single page. The page must be corrupt */ + return SQLITE_CORRUPT_BKPT; + } + testcase( pPage->nCell==MX_CELL(pBt) ); + /* EVIDENCE-OF: R-24089-57979 If a page contains no cells (which is only + ** possible for a root page of a table that contains no rows) then the + ** offset to the cell content area will equal the page size minus the + ** bytes of reserved space. */ + assert( pPage->nCell>0 || top==usableSize || CORRUPT_DB ); - /* A malformed database page might cause us to read past the end - ** of page when parsing a cell. - ** - ** The following block of code checks early to see if a cell extends - ** past the end of a page boundary and causes SQLITE_CORRUPT to be - ** returned if it does. - */ - iCellFirst = cellOffset + 2*pPage->nCell; - iCellLast = usableSize - 4; - if( pBt->db->flags & SQLITE_CellSizeCk ){ - int i; /* Index into the cell pointer array */ - int sz; /* Size of a cell */ - - if( !pPage->leaf ) iCellLast--; - for(i=0; inCell; i++){ - pc = get2byteAligned(&data[cellOffset+i*2]); - testcase( pc==iCellFirst ); - testcase( pc==iCellLast ); - if( pciCellLast ){ - return SQLITE_CORRUPT_BKPT; - } - sz = pPage->xCellSize(pPage, &data[pc]); - testcase( pc+sz==usableSize ); - if( pc+sz>usableSize ){ - return SQLITE_CORRUPT_BKPT; - } - } - if( !pPage->leaf ) iCellLast++; - } - - /* Compute the total free space on the page - ** EVIDENCE-OF: R-23588-34450 The two-byte integer at offset 1 gives the - ** start of the first freeblock on the page, or is zero if there are no - ** freeblocks. */ - pc = get2byte(&data[hdr+1]); - nFree = data[hdr+7] + top; /* Init nFree to non-freeblock free space */ - if( pc>0 ){ - u32 next, size; - if( pciCellLast ){ - return SQLITE_CORRUPT_BKPT; /* Freeblock off the end of the page */ - } - next = get2byte(&data[pc]); - size = get2byte(&data[pc+2]); - nFree = nFree + size; - if( next<=pc+size+3 ) break; - pc = next; - } - if( next>0 ){ - return SQLITE_CORRUPT_BKPT; /* Freeblock not in ascending order */ + /* A malformed database page might cause us to read past the end + ** of page when parsing a cell. + ** + ** The following block of code checks early to see if a cell extends + ** past the end of a page boundary and causes SQLITE_CORRUPT to be + ** returned if it does. + */ + iCellFirst = cellOffset + 2*pPage->nCell; + iCellLast = usableSize - 4; + if( pBt->db->flags & SQLITE_CellSizeCk ){ + int i; /* Index into the cell pointer array */ + int sz; /* Size of a cell */ + + if( !pPage->leaf ) iCellLast--; + for(i=0; inCell; i++){ + pc = get2byteAligned(&data[cellOffset+i*2]); + testcase( pc==iCellFirst ); + testcase( pc==iCellLast ); + if( pciCellLast ){ + return SQLITE_CORRUPT_BKPT; } - if( pc+size>(unsigned int)usableSize ){ - return SQLITE_CORRUPT_BKPT; /* Last freeblock extends past page end */ + sz = pPage->xCellSize(pPage, &data[pc]); + testcase( pc+sz==usableSize ); + if( pc+sz>usableSize ){ + return SQLITE_CORRUPT_BKPT; } } - - /* At this point, nFree contains the sum of the offset to the start - ** of the cell-content area plus the number of free bytes within - ** the cell-content area. If this is greater than the usable-size - ** of the page, then the page must be corrupted. This check also - ** serves to verify that the offset to the start of the cell-content - ** area, according to the page header, lies within the page. - */ - if( nFree>usableSize ){ + if( !pPage->leaf ) iCellLast++; + } + + /* Compute the total free space on the page + ** EVIDENCE-OF: R-23588-34450 The two-byte integer at offset 1 gives the + ** start of the first freeblock on the page, or is zero if there are no + ** freeblocks. */ + pc = get2byte(&data[hdr+1]); + nFree = data[hdr+7] + top; /* Init nFree to non-freeblock free space */ + if( pc>0 ){ + u32 next, size; + if( pcnFree = (u16)(nFree - iCellFirst); - pPage->isInit = 1; + while( 1 ){ + if( pc>iCellLast ){ + return SQLITE_CORRUPT_BKPT; /* Freeblock off the end of the page */ + } + next = get2byte(&data[pc]); + size = get2byte(&data[pc+2]); + nFree = nFree + size; + if( next<=pc+size+3 ) break; + pc = next; + } + if( next>0 ){ + return SQLITE_CORRUPT_BKPT; /* Freeblock not in ascending order */ + } + if( pc+size>(unsigned int)usableSize ){ + return SQLITE_CORRUPT_BKPT; /* Last freeblock extends past page end */ + } } + + /* At this point, nFree contains the sum of the offset to the start + ** of the cell-content area plus the number of free bytes within + ** the cell-content area. If this is greater than the usable-size + ** of the page, then the page must be corrupted. This check also + ** serves to verify that the offset to the start of the cell-content + ** area, according to the page header, lies within the page. + */ + if( nFree>usableSize ){ + return SQLITE_CORRUPT_BKPT; + } + pPage->nFree = (u16)(nFree - iCellFirst); + pPage->isInit = 1; return SQLITE_OK; } @@ -3360,7 +3357,7 @@ static int setChildPtrmaps(MemPage *pPage){ Pgno pgno = pPage->pgno; assert( sqlite3_mutex_held(pPage->pBt->mutex) ); - rc = btreeInitPage(pPage); + rc = pPage->isInit ? SQLITE_OK : btreeInitPage(pPage); if( rc!=SQLITE_OK ) return rc; nCell = pPage->nCell; @@ -3411,7 +3408,7 @@ static int modifyPagePointer(MemPage *pPage, Pgno iFrom, Pgno iTo, u8 eType){ int nCell; int rc; - rc = btreeInitPage(pPage); + rc = pPage->isInit ? SQLITE_OK : btreeInitPage(pPage); if( rc ) return rc; nCell = pPage->nCell; -- 2.47.2