Many hyperlinks are disabled.
Use anonymous login
to enable hyperlinks.
Overview
Comment: | Smaller and faster implementation of exprMightBeIndexed(). |
---|---|
Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA3-256: |
76cd611d41465fcec61c21520d55172c |
User & Date: | drh 2017-04-11 18:06:48.387 |
Context
2017-04-11
| ||
19:00 | Update this branch with latest trunk changes. (check-in: 0f66a09393 user: dan tags: schemalint) | |
18:55 | Limit the depth of recursion for valid JSON in the JSON1 extension in order to avoid using excess stack space in the recursive descent parser. Fix for ticket [981329adeef51011052667a9]. (check-in: 1f68c18459 user: drh tags: trunk) | |
18:06 | Smaller and faster implementation of exprMightBeIndexed(). (check-in: 76cd611d41 user: drh tags: trunk) | |
16:44 | Very slight smaller and faster sqlite3SelectNew() (check-in: 4143650c4c user: drh tags: trunk) | |
Changes
Changes to src/whereexpr.c.
︙ | ︙ | |||
826 827 828 829 830 831 832 | return mask; } /* ** Expression pExpr is one operand of a comparison operator that might ** be useful for indexing. This routine checks to see if pExpr appears ** in any index. Return TRUE (1) if pExpr is an indexed term and return | | | | < > | < < > > > > > > > > > > | > > > > > > > > > > > | | < < < < < < < < < | < < < < | 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 | return mask; } /* ** Expression pExpr is one operand of a comparison operator that might ** be useful for indexing. This routine checks to see if pExpr appears ** in any index. Return TRUE (1) if pExpr is an indexed term and return ** FALSE (0) if not. If TRUE is returned, also set aiCurCol[0] to the cursor ** number of the table that is indexed and aiCurCol[1] to the column number ** of the column that is indexed, or XN_EXPR (-2) if an expression is being ** indexed. ** ** If pExpr is a TK_COLUMN column reference, then this routine always returns ** true even if that particular column is not indexed, because the column ** might be added to an automatic index later. */ static SQLITE_NOINLINE int exprMightBeIndexed2( SrcList *pFrom, /* The FROM clause */ Bitmask mPrereq, /* Bitmask of FROM clause terms referenced by pExpr */ int *aiCurCol, /* Write the referenced table cursor and column here */ Expr *pExpr /* An operand of a comparison operator */ ){ Index *pIdx; int i; int iCur; for(i=0; mPrereq>1; i++, mPrereq>>=1){} iCur = pFrom->a[i].iCursor; for(pIdx=pFrom->a[i].pTab->pIndex; pIdx; pIdx=pIdx->pNext){ if( pIdx->aColExpr==0 ) continue; for(i=0; i<pIdx->nKeyCol; i++){ if( pIdx->aiColumn[i]!=XN_EXPR ) continue; if( sqlite3ExprCompareSkip(pExpr, pIdx->aColExpr->a[i].pExpr, iCur)==0 ){ aiCurCol[0] = iCur; aiCurCol[1] = XN_EXPR; return 1; } } } return 0; } static int exprMightBeIndexed( SrcList *pFrom, /* The FROM clause */ Bitmask mPrereq, /* Bitmask of FROM clause terms referenced by pExpr */ int *aiCurCol, /* Write the referenced table cursor & column here */ Expr *pExpr, /* An operand of a comparison operator */ int op /* The specific comparison operator */ ){ /* If this expression is a vector to the left or right of a ** inequality constraint (>, <, >= or <=), perform the processing ** on the first element of the vector. */ assert( TK_GT+1==TK_LE && TK_GT+2==TK_LT && TK_GT+3==TK_GE ); assert( TK_IS<TK_GE && TK_ISNULL<TK_GE && TK_IN<TK_GE ); assert( op<=TK_GE ); if( pExpr->op==TK_VECTOR && (op>=TK_GT && ALWAYS(op<=TK_GE)) ){ pExpr = pExpr->x.pList->a[0].pExpr; } if( pExpr->op==TK_COLUMN ){ aiCurCol[0] = pExpr->iTable; aiCurCol[1] = pExpr->iColumn; return 1; } if( mPrereq==0 ) return 0; /* No table references */ if( (mPrereq&(mPrereq-1))!=0 ) return 0; /* Refs more than one table */ return exprMightBeIndexed2(pFrom,mPrereq,aiCurCol,pExpr); } /* ** The input to this routine is an WhereTerm structure with only the ** "pExpr" field filled in. The job of this routine is to analyze the ** subexpression and populate all the other fields of the WhereTerm ** structure. |
︙ | ︙ | |||
957 958 959 960 961 962 963 | } } pTerm->prereqAll = prereqAll; pTerm->leftCursor = -1; pTerm->iParent = -1; pTerm->eOperator = 0; if( allowedOp(op) ){ | | | | | | | 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 | } } pTerm->prereqAll = prereqAll; pTerm->leftCursor = -1; pTerm->iParent = -1; pTerm->eOperator = 0; if( allowedOp(op) ){ int aiCurCol[2]; Expr *pLeft = sqlite3ExprSkipCollate(pExpr->pLeft); Expr *pRight = sqlite3ExprSkipCollate(pExpr->pRight); u16 opMask = (pTerm->prereqRight & prereqLeft)==0 ? WO_ALL : WO_EQUIV; if( pTerm->iField>0 ){ assert( op==TK_IN ); assert( pLeft->op==TK_VECTOR ); pLeft = pLeft->x.pList->a[pTerm->iField-1].pExpr; } if( exprMightBeIndexed(pSrc, prereqLeft, aiCurCol, pLeft, op) ){ pTerm->leftCursor = aiCurCol[0]; pTerm->u.leftColumn = aiCurCol[1]; pTerm->eOperator = operatorMask(op) & opMask; } if( op==TK_IS ) pTerm->wtFlags |= TERM_IS; if( pRight && exprMightBeIndexed(pSrc, pTerm->prereqRight, aiCurCol, pRight, op) ){ WhereTerm *pNew; Expr *pDup; u16 eExtraOp = 0; /* Extra bits for pNew->eOperator */ assert( pTerm->iField==0 ); if( pTerm->leftCursor>=0 ){ int idxNew; |
︙ | ︙ | |||
1005 1006 1007 1008 1009 1010 1011 | eExtraOp = WO_EQUIV; } }else{ pDup = pExpr; pNew = pTerm; } exprCommute(pParse, pDup); | | | | 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 | eExtraOp = WO_EQUIV; } }else{ pDup = pExpr; pNew = pTerm; } exprCommute(pParse, pDup); pNew->leftCursor = aiCurCol[0]; pNew->u.leftColumn = aiCurCol[1]; testcase( (prereqLeft | extraRight) != prereqLeft ); pNew->prereqRight = prereqLeft | extraRight; pNew->prereqAll = prereqAll; pNew->eOperator = (operatorMask(pDup->op) + eExtraOp) & opMask; } } |
︙ | ︙ |