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Overview
| Comment: | Clearer presentation of the logic. No functional changes. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | skip-scan-improvement |
| Files: | files | file ages | folders |
| SHA1: |
a3dcf6db76cc09bdfedb1bbeba3b359b |
| User & Date: | drh 2016-02-22 21:19:54 |
Context
|
2016-02-22
| ||
| 23:14 | Avoid an unnecessary seek operation some corner-case skip-scan operations. check-in: 2a6003a9 user: drh tags: trunk | |
| 21:19 | Clearer presentation of the logic. No functional changes. Closed-Leaf check-in: a3dcf6db user: drh tags: skip-scan-improvement | |
| 20:52 | Avoid an unnecessary seek operation on some corner-case skip-scans. check-in: 38e837e6 user: drh tags: skip-scan-improvement | |
Changes
Changes to src/wherecode.c.
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}else if( bSeekPastNull ){
sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
nConstraint++;
startEq = 0;
start_constraints = 1;
}
codeApplyAffinity(pParse, regBase, nConstraint - bSeekPastNull, zStartAff);
if( pLoop->nSkip==0 || nConstraint>pLoop->nSkip ){
op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev];
assert( op!=0 );
sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
VdbeCoverage(v);
VdbeCoverageIf(v, op==OP_Rewind); testcase( op==OP_Rewind );
VdbeCoverageIf(v, op==OP_Last); testcase( op==OP_Last );
VdbeCoverageIf(v, op==OP_SeekGT); testcase( op==OP_SeekGT );
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| > > > > |
1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 |
}else if( bSeekPastNull ){
sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
nConstraint++;
startEq = 0;
start_constraints = 1;
}
codeApplyAffinity(pParse, regBase, nConstraint - bSeekPastNull, zStartAff);
if( pLoop->nSkip>0 && nConstraint==pLoop->nSkip ){
/* The skip-scan logic inside the call to codeAllEqualityConstraints()
** above has already left the cursor sitting on the correct row,
** so no further seeking is needed */
}else{
op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev];
assert( op!=0 );
sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
VdbeCoverage(v);
VdbeCoverageIf(v, op==OP_Rewind); testcase( op==OP_Rewind );
VdbeCoverageIf(v, op==OP_Last); testcase( op==OP_Last );
VdbeCoverageIf(v, op==OP_SeekGT); testcase( op==OP_SeekGT );
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