From: drh Date: Fri, 1 Aug 2014 21:00:53 +0000 (+0000) Subject: Improved detection and handling of NULL values on the RHS of a IN operator. X-Git-Tag: version-3.8.6~39 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6be515ebe0c6976352efd82cd6cddebe4b43361f;p=thirdparty%2Fsqlite.git Improved detection and handling of NULL values on the RHS of a IN operator. FossilOrigin-Name: 468e730036edac22cfeb9ea3515aa16e6bcd6650 --- diff --git a/manifest b/manifest index 2762bc4675..5a22fd3d13 100644 --- a/manifest +++ b/manifest @@ -1,5 +1,5 @@ -C Remove\san\sunnecessary\sOP_Null\sin\sthe\sIN-operator\slogic.\s\sAttempt\sto\sclarify\ncomments\sexplaining\sthe\sIN-operator\scode,\sthough\sit\sis\snot\sclear\sthat\sthe\ncomments\sare\scorrect\seven\syet\s-\smore\swork\sto\sbe\sdone. -D 2014-08-01T18:00:24.770 +C Improved\sdetection\sand\shandling\sof\sNULL\svalues\son\sthe\sRHS\sof\sa\sIN\soperator. +D 2014-08-01T21:00:53.855 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f F Makefile.in 5eb79e334a5de69c87740edd56af6527dd219308 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23 @@ -176,7 +176,7 @@ F src/complete.c dc1d136c0feee03c2f7550bafc0d29075e36deac F src/ctime.c 0231df905e2c4abba4483ee18ffc05adc321df2a F src/date.c 593c744b2623971e45affd0bde347631bdfa4625 F src/delete.c bcf8f72126cea80fc3d5bc5494cf19b3f8935aaf -F src/expr.c 45da7f2dd6b5c52b3210387956711d578bdceb37 +F src/expr.c ac35f4c83ccc090e4b31bf3c839d519762a86fd5 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb F src/fkey.c 8545f3b36da47473e10800ea4fb0810fd4062514 F src/func.c 3bc223ea36cd29a91c481485343d0ee4257ab8dc @@ -1185,7 +1185,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f -P 7c6fbcfe6ed5739e8e4639b7b123fbf9828cbfc0 -R 76f22de612006799aae8055deaa164fe +P c11e55fabbc718cb324ecd3540453c25db98f50c +R d4c66ce9989f6295fb51f65762a6a30b U drh -Z ebc1ba4c7f530e221b3bc2fcb7e1119a +Z 526f21f790d2042539b4ae116e22530d diff --git a/manifest.uuid b/manifest.uuid index ef13592241..4742ee228e 100644 --- a/manifest.uuid +++ b/manifest.uuid @@ -1 +1 @@ -c11e55fabbc718cb324ecd3540453c25db98f50c \ No newline at end of file +468e730036edac22cfeb9ea3515aa16e6bcd6650 \ No newline at end of file diff --git a/src/expr.c b/src/expr.c index 591ea9845c..6440dea397 100644 --- a/src/expr.c +++ b/src/expr.c @@ -1475,6 +1475,22 @@ int sqlite3CodeOnce(Parse *pParse){ return sqlite3VdbeAddOp1(v, OP_Once, pParse->nOnce++); } +/* +** Generate code that checks the single-column index table iCur to see if +** contains any NULL entries. Cause the register at regHasNull to be set +** to a non-NULL value if iCur contains no NULLs. Cause register regHasNull +** to be set to NULL if iCur contains one or more NULL values. +*/ +static void sqlite3SetHasNullFlag(Vdbe *v, int iCur, int regHasNull){ + int j1; + sqlite3VdbeAddOp2(v, OP_Integer, 0, regHasNull); + j1 = sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v); + sqlite3VdbeAddOp3(v, OP_Column, iCur, 0, regHasNull); + sqlite3VdbeChangeP5(v, OPFLAG_TYPEOFARG); + VdbeComment((v, "")); + sqlite3VdbeJumpHere(v, j1); +} + /* ** This function is used by the implementation of the IN (...) operator. ** The pX parameter is the expression on the RHS of the IN operator, which @@ -1532,24 +1548,9 @@ int sqlite3CodeOnce(Parse *pParse){ ** NULL value, then *prRhsHasNull is left unchanged. ** ** If a register is allocated and its location stored in *prRhsHasNull, then -** the value in that register will be: -** -** 0 if the (...) contains no NULL values -** 1 if the (...) does not contain NULL values -** NULL if we do not yet know if (...) contains NULLs -** -** If the (...) does not remain constant for the duration of the query -** (i.e. the SELECT within the (...) is a correlated subquery) then the -** value of the allocated register is reset to NULL each time the subquery -** is rerun. This allows the caller to use vdbe code equivalent to the -** following: -** -** if( r[*prRhsHasNull] IS NULL ){ -** r[*prRhsHasNull] = -** } -** -** in order to avoid running the -** test more often than is necessary. +** the value in that register will be NULL if the b-tree contains one or more +** NULL values, and it will be some non-NULL value if the b-tree contains no +** NULL values. */ #ifndef SQLITE_OMIT_SUBQUERY int sqlite3FindInIndex(Parse *pParse, Expr *pX, u32 inFlags, int *prRhsHasNull){ @@ -1628,7 +1629,7 @@ int sqlite3FindInIndex(Parse *pParse, Expr *pX, u32 inFlags, int *prRhsHasNull){ if( prRhsHasNull && !pTab->aCol[iCol].notNull ){ *prRhsHasNull = ++pParse->nMem; - sqlite3VdbeAddOp2(v, OP_Null, 0, *prRhsHasNull); + sqlite3SetHasNullFlag(v, iTab, *prRhsHasNull); } sqlite3VdbeJumpHere(v, iAddr); } @@ -1691,10 +1692,10 @@ int sqlite3FindInIndex(Parse *pParse, Expr *pX, u32 inFlags, int *prRhsHasNull){ int sqlite3CodeSubselect( Parse *pParse, /* Parsing context */ Expr *pExpr, /* The IN, SELECT, or EXISTS operator */ - int rMayHaveNull, /* Register that records whether NULLs exist in RHS */ + int rHasNullFlag, /* Register that records whether NULLs exist in RHS */ int isRowid /* If true, LHS of IN operator is a rowid */ ){ - int testAddr = -1; /* One-time test address */ + int jmpIfDynamic = -1; /* One-time test address */ int rReg = 0; /* Register storing resulting */ Vdbe *v = sqlite3GetVdbe(pParse); if( NEVER(v==0) ) return 0; @@ -1711,13 +1712,13 @@ int sqlite3CodeSubselect( ** save the results, and reuse the same result on subsequent invocations. */ if( !ExprHasProperty(pExpr, EP_VarSelect) ){ - testAddr = sqlite3CodeOnce(pParse); VdbeCoverage(v); + jmpIfDynamic = sqlite3CodeOnce(pParse); VdbeCoverage(v); } #ifndef SQLITE_OMIT_EXPLAIN if( pParse->explain==2 ){ char *zMsg = sqlite3MPrintf( - pParse->db, "EXECUTE %s%s SUBQUERY %d", testAddr>=0?"":"CORRELATED ", + pParse->db, "EXECUTE %s%s SUBQUERY %d", jmpIfDynamic>=0?"":"CORRELATED ", pExpr->op==TK_IN?"LIST":"SCALAR", pParse->iNextSelectId ); sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC); @@ -1731,10 +1732,6 @@ int sqlite3CodeSubselect( Expr *pLeft = pExpr->pLeft; /* the LHS of the IN operator */ KeyInfo *pKeyInfo = 0; /* Key information */ - if( rMayHaveNull ){ - sqlite3VdbeAddOp2(v, OP_Null, 0, rMayHaveNull); - } - affinity = sqlite3ExprAffinity(pLeft); /* Whether this is an 'x IN(SELECT...)' or an 'x IN()' @@ -1817,9 +1814,9 @@ int sqlite3CodeSubselect( ** this code only executes once. Because for a non-constant ** expression we need to rerun this code each time. */ - if( testAddr>=0 && !sqlite3ExprIsConstant(pE2) ){ - sqlite3VdbeChangeToNoop(v, testAddr); - testAddr = -1; + if( jmpIfDynamic>=0 && !sqlite3ExprIsConstant(pE2) ){ + sqlite3VdbeChangeToNoop(v, jmpIfDynamic); + jmpIfDynamic = -1; } /* Evaluate the expression and insert it into the temp table */ @@ -1889,8 +1886,12 @@ int sqlite3CodeSubselect( } } - if( testAddr>=0 ){ - sqlite3VdbeJumpHere(v, testAddr); + if( rHasNullFlag ){ + sqlite3SetHasNullFlag(v, pExpr->iTable, rHasNullFlag); + } + + if( jmpIfDynamic>=0 ){ + sqlite3VdbeJumpHere(v, jmpIfDynamic); } sqlite3ExprCachePop(pParse); @@ -1911,7 +1912,7 @@ int sqlite3CodeSubselect( ** if the LHS is NULL or if the LHS is not contained within the RHS and the ** RHS contains one or more NULL values. ** -** This routine generates code will jump to destIfFalse if the LHS is not +** This routine generates code that jumps to destIfFalse if the LHS is not ** contained within the RHS. If due to NULLs we cannot determine if the LHS ** is contained in the RHS then jump to destIfNull. If the LHS is contained ** within the RHS then fall through. @@ -1997,34 +1998,19 @@ static void sqlite3ExprCodeIN( ** the presence of a NULL on the RHS makes a difference in the ** outcome. */ - int j1, j2; + int j1; /* First check to see if the LHS is contained in the RHS. If so, - ** then the presence of NULLs in the RHS does not matter, so jump - ** over all of the code that follows. + ** then the answer is TRUE the presence of NULLs in the RHS does + ** not matter. If the LHS is not contained in the RHS, then the + ** answer is NULL if the RHS contains NULLs and the answer is + ** FALSE if the RHS is NULL-free. */ j1 = sqlite3VdbeAddOp4Int(v, OP_Found, pExpr->iTable, 0, r1, 1); VdbeCoverage(v); - - /* Here we begin generating code that runs if the LHS is not - ** contained within the RHS. Generate additional code that - ** tests the RHS for NULLs. If the RHS contains a NULL then - ** jump to destIfNull. If there are no NULLs in the RHS then - ** jump to destIfFalse. - */ - sqlite3VdbeAddOp2(v, OP_If, rRhsHasNull, destIfNull); VdbeCoverage(v); - sqlite3VdbeAddOp2(v, OP_IfNot, rRhsHasNull, destIfFalse); VdbeCoverage(v); - j2 = sqlite3VdbeAddOp4Int(v, OP_Found, pExpr->iTable, 0, rRhsHasNull, 1); + sqlite3VdbeAddOp2(v, OP_IsNull, rRhsHasNull, destIfNull); VdbeCoverage(v); - sqlite3VdbeAddOp2(v, OP_Integer, 0, rRhsHasNull); sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfFalse); - sqlite3VdbeJumpHere(v, j2); - sqlite3VdbeAddOp2(v, OP_Integer, 1, rRhsHasNull); - sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfNull); - - /* The OP_Found at the top of this branch jumps here when true, - ** causing the overall IN expression evaluation to fall through. - */ sqlite3VdbeJumpHere(v, j1); } }