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Overview
| Comment: | Simplify the range scan code generate while also avoiding an unnecessary OP_Affinity opcode. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | expr-codegen-enhancement |
| Files: | files | file ages | folders |
| SHA1: |
372686bfbb1da08b04bddb085e30da5d |
| User & Date: | drh 2013-11-15 12:41:01.696 |
Context
|
2013-11-15
| ||
| 15:52 | Improvements to the Expr comparison routine to make it more general. Improvements to unary-minus code generation so that it can make use of a global constant register with a zero value. (check-in: 835be656bb user: drh tags: expr-codegen-enhancement) | |
| 12:41 | Simplify the range scan code generate while also avoiding an unnecessary OP_Affinity opcode. (check-in: 372686bfbb user: drh tags: expr-codegen-enhancement) | |
| 03:30 | Merge EXPLAIN fixes from trunk. (check-in: cd579727b1 user: drh tags: expr-codegen-enhancement) | |
Changes
Changes to src/where.c.
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int start_constraints; /* Start of range is constrained */
int nConstraint; /* Number of constraint terms */
Index *pIdx; /* The index we will be using */
int iIdxCur; /* The VDBE cursor for the index */
int nExtraReg = 0; /* Number of extra registers needed */
int op; /* Instruction opcode */
char *zStartAff; /* Affinity for start of range constraint */
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int start_constraints; /* Start of range is constrained */
int nConstraint; /* Number of constraint terms */
Index *pIdx; /* The index we will be using */
int iIdxCur; /* The VDBE cursor for the index */
int nExtraReg = 0; /* Number of extra registers needed */
int op; /* Instruction opcode */
char *zStartAff; /* Affinity for start of range constraint */
char cEndAff = 0; /* Affinity for end of range constraint */
pIdx = pLoop->u.btree.pIndex;
iIdxCur = pLevel->iIdxCur;
assert( nEq>=pLoop->u.btree.nSkip );
/* If this loop satisfies a sort order (pOrderBy) request that
** was passed to this function to implement a "SELECT min(x) ..."
|
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}
/* Generate code to evaluate all constraint terms using == or IN
** and store the values of those terms in an array of registers
** starting at regBase.
*/
regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff);
| > | | 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 |
}
/* Generate code to evaluate all constraint terms using == or IN
** and store the values of those terms in an array of registers
** starting at regBase.
*/
regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff);
assert( zStartAff==0 || sqlite3Strlen30(zStartAff)>=nEq );
if( zStartAff ) cEndAff = zStartAff[nEq];
addrNxt = pLevel->addrNxt;
/* If we are doing a reverse order scan on an ascending index, or
** a forward order scan on a descending index, interchange the
** start and end terms (pRangeStart and pRangeEnd).
*/
if( (nEq<pIdx->nKeyCol && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC))
|
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if( pRangeEnd ){
Expr *pRight = pRangeEnd->pExpr->pRight;
sqlite3ExprCacheRemove(pParse, regBase+nEq, 1);
sqlite3ExprCode(pParse, pRight, regBase+nEq);
if( (pRangeEnd->wtFlags & TERM_VNULL)==0 ){
sqlite3ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
}
| < | < < < < < | > | | < < < | 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 |
if( pRangeEnd ){
Expr *pRight = pRangeEnd->pExpr->pRight;
sqlite3ExprCacheRemove(pParse, regBase+nEq, 1);
sqlite3ExprCode(pParse, pRight, regBase+nEq);
if( (pRangeEnd->wtFlags & TERM_VNULL)==0 ){
sqlite3ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
}
if( sqlite3CompareAffinity(pRight, cEndAff)!=SQLITE_AFF_NONE
&& !sqlite3ExprNeedsNoAffinityChange(pRight, cEndAff)
){
codeApplyAffinity(pParse, regBase+nEq, 1, &cEndAff);
}
nConstraint++;
testcase( pRangeEnd->wtFlags & TERM_VIRTUAL );
}
sqlite3DbFree(db, zStartAff);
/* Top of the loop body */
pLevel->p2 = sqlite3VdbeCurrentAddr(v);
/* Check if the index cursor is past the end of the range. */
op = aEndOp[(pRangeEnd || nEq) * (1 + bRev)];
testcase( op==OP_Noop );
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