From 380d68513316fa6fabd50f222ed8c5d68fc7376d Mon Sep 17 00:00:00 2001 From: drh Date: Wed, 20 Nov 2013 20:58:00 +0000 Subject: [PATCH] Improved comments on the OP_Column changes. Optimize out loading of overflow pages for content with zero length. Add test cases for the latter. FossilOrigin-Name: 0e05679db7aa302a49e087a81f85203844b98cbe --- manifest | 14 +++++++------- manifest.uuid | 2 +- src/vdbe.c | 46 +++++++++++++++++++++++++--------------------- test/func.test | 18 ++++++++++++++++++ 4 files changed, 51 insertions(+), 29 deletions(-) diff --git a/manifest b/manifest index a7de779afd..a137e832e8 100644 --- a/manifest +++ b/manifest @@ -1,5 +1,5 @@ -C Further\sperformance\stweaks\sto\sOP_Column. -D 2013-11-20T19:28:03.982 +C Improved\scomments\son\sthe\sOP_Column\schanges.\s\sOptimize\sout\sloading\sof\soverflow\npages\sfor\scontent\swith\szero\slength.\s\sAdd\stest\scases\sfor\sthe\slatter. +D 2013-11-20T20:58:00.360 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f F Makefile.in 8a07bebafbfda0eb67728f4bd15a36201662d1a1 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23 @@ -280,7 +280,7 @@ F src/update.c c05a0ee658f1a149e0960dfd110f3b8bd846bcb0 F src/utf.c 6fc6c88d50448c469c5c196acf21617a24f90269 F src/util.c 2fa6c821d28bbdbeec1b2a7b091a281c9ef8f918 F src/vacuum.c 3728d74919d4fb1356f9e9a13e27773db60b7179 -F src/vdbe.c 1a6e2c9413fca3b2d00c49e85a861e0adc8b6c6a +F src/vdbe.c 987f375b8ba5b5c3d0ded64191f72706221f76f9 F src/vdbe.h c06f0813f853566457ce9cfb1a4a4bc39a5da644 F src/vdbeInt.h fbae1c449049a1a26ebbdf44e1beb08344072b72 F src/vdbeapi.c 93a22a9ba2abe292d5c2cf304d7eb2e894dde0ed @@ -573,7 +573,7 @@ F test/fts4merge4.test c19c85ca1faa7b6d536832b49c12e1867235f584 F test/fts4noti.test aed33ba44808852dcb24bf70fa132e7bf530f057 F test/fts4unicode.test e28ba1a14181e709dcdf47455f207adf14c7cfe0 F test/full.test 6b3c8fb43c6beab6b95438c1675374b95fab245d -F test/func.test c7e80a44eebac8604397eb2ad83d0d5d9d541237 +F test/func.test 00667bbeac044d007f6f021af1b9f6150f0c7ff8 F test/func2.test 772d66227e4e6684b86053302e2d74a2500e1e0f F test/func3.test dbccee9133cfef1473c59ec07b5f0262b9d72f9a F test/func4.test 6beacdfcb0e18c358e6c2dcacf1b65d1fa80955f @@ -1140,7 +1140,7 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4 F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff -P 7c914e3997d2b28164a2fa7eb4398262b6ddb4b2 -R 72749b37eba95a49879e9308fdcd90bb +P 0e3f5df695216a27602a53eed5d25231b055adc8 +R 7b4a6a3b4e08d369fabb1ea696a3ba02 U drh -Z 441207295dddfadd80f4cc85b77f0a53 +Z a02194f256e2495862011254263d6e91 diff --git a/manifest.uuid b/manifest.uuid index 458e461e6b..d385d476cd 100644 --- a/manifest.uuid +++ b/manifest.uuid @@ -1 +1 @@ -0e3f5df695216a27602a53eed5d25231b055adc8 \ No newline at end of file +0e05679db7aa302a49e087a81f85203844b98cbe \ No newline at end of file diff --git a/src/vdbe.c b/src/vdbe.c index f3832ab34f..e70cd49ae0 100644 --- a/src/vdbe.c +++ b/src/vdbe.c @@ -2284,11 +2284,11 @@ case OP_Column: { aType = pC->aType; aOffset = pC->aOffset; #ifndef SQLITE_OMIT_VIRTUALTABLE - assert( pC->pVtabCursor==0 ); + assert( pC->pVtabCursor==0 ); /* OP_Column never called on virtual table */ #endif pCrsr = pC->pCursor; - assert( pCrsr!=0 || pC->pseudoTableReg>0 ); - assert( pC->pseudoTableReg==0 || pC->nullRow ); + assert( pCrsr!=0 || pC->pseudoTableReg>0 ); /* pCrsr NULL on PseudoTables */ + assert( pCrsr!=0 || pC->nullRow ); /* pC->nullRow on PseudoTables */ /* If the cursor cache is stale, bring it up-to-date */ rc = sqlite3VdbeCursorMoveto(pC); @@ -2339,12 +2339,15 @@ case OP_Column: { goto too_big; } } - pC->cacheStatus = p->cacheCtr; pC->iHdrOffset = getVarint32(pC->aRow, offset); pC->nHdrParsed = 0; aOffset[0] = offset; if( availaRow does not have to hold the entire row, but it does at least + ** need to cover the header of the record. If pC->aRow does not contain + ** the complete header, then set it to zero, forcing the header to be + ** dynamically allocated. */ pC->aRow = 0; pC->szRow = 0; } @@ -2368,8 +2371,8 @@ case OP_Column: { ** parsed and valid information is in aOffset[] and aType[]. */ if( pC->nHdrParsed<=p2 ){ - /* If there is more header available for parsing, try to extract - ** additional fields up through the p2-th field + /* If there is more header available for parsing in the record, try + ** to extract additional fields up through the p2+1-th field */ if( pC->iHdrOffsetnHdrParsed<=p2 ){ if( pOp->p4type==P4_MEM ){ sqlite3VdbeMemShallowCopy(pDest, pOp->p4.pMem, MEM_Static); @@ -2443,33 +2447,33 @@ case OP_Column: { } } - /* Get the column information. If aOffset[p2] is non-zero, then - ** deserialize the value from the record. If aOffset[p2] is zero, - ** then there are not enough fields in the record to satisfy the - ** request. In this case, set the value NULL or to P4 if P4 is - ** a pointer to a Mem object. + /* Extract the content for the p2+1-th column. Control can only + ** reach this point if aOffset[p2], aOffset[p2+1], and aType[p2] are + ** all valid. */ assert( p2nHdrParsed ); assert( rc==SQLITE_OK ); if( pC->szRow>=aOffset[p2+1] ){ - /* This is the common case where the whole row fits on a single page */ + /* This is the common case where the desired content fits on the original + ** page - where the content is not on an overflow page */ VdbeMemRelease(pDest); sqlite3VdbeSerialGet(pC->aRow+aOffset[p2], aType[p2], pDest); }else{ - /* This branch happens only when the row overflows onto multiple pages */ + /* This branch happens only when content is on overflow pages */ t = aType[p2]; - if( (pOp->p5 & (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG))!=0 - && ((t>=12 && (t&1)==0) || (pOp->p5 & OPFLAG_TYPEOFARG)!=0) + if( ((pOp->p5 & (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG))!=0 + && ((t>=12 && (t&1)==0) || (pOp->p5 & OPFLAG_TYPEOFARG)!=0)) + || (len = sqlite3VdbeSerialTypeLen(t))==0 ){ /* Content is irrelevant for the typeof() function and for ** the length(X) function if X is a blob. So we might as well use ** bogus content rather than reading content from disk. NULL works ** for text and blob and whatever is in the payloadSize64 variable - ** will work for everything else. */ - zData = t<12 ? (u8*)&payloadSize64 : 0; + ** will work for everything else. Content is also irrelevant if + ** the content length is 0. */ + zData = t<=13 ? (u8*)&payloadSize64 : 0; sMem.zMalloc = 0; }else{ - len = sqlite3VdbeSerialTypeLen(t); memset(&sMem, 0, sizeof(sMem)); sqlite3VdbeMemMove(&sMem, pDest); rc = sqlite3VdbeMemFromBtree(pCrsr, aOffset[p2], len, pC->isIndex, diff --git a/test/func.test b/test/func.test index 7c7d55e1b7..edec591eae 100644 --- a/test/func.test +++ b/test/func.test @@ -1319,6 +1319,24 @@ do_test func-29.6 { set x } {1} +# The OP_Column opcode has an optimization that avoids loading content +# for fields with content-length=0 when the content offset is on an overflow +# page. Make sure the optimization works. +# +do_execsql_test func-29.10 { + CREATE TABLE t29b(a,b,c,d,e,f,g,h,i); + INSERT INTO t29b + VALUES(1, hex(randomblob(2000)), null, 0, 1, '', zeroblob(0),'x',x'01'); + SELECT typeof(c), typeof(d), typeof(e), typeof(f), + typeof(g), typeof(h), typeof(i) FROM t29b; +} {null integer integer text blob text blob} +do_execsql_test func-29.11 { + SELECT length(f), length(g), length(h), length(i) FROM t29b; +} {0 0 1 1} +do_execsql_test func-29.12 { + SELECT quote(f), quote(g), quote(h), quote(i) FROM t29b; +} {'' X'' 'x' X'01'} + # EVIDENCE-OF: R-29701-50711 The unicode(X) function returns the numeric # unicode code point corresponding to the first character of the string # X.