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Overview
Comment:Avoid an unnecessary seek operation on some corner-case skip-scans.
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Timelines: family | ancestors | descendants | both | skip-scan-improvement
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SHA1: 38e837e605076124b73235e1fd832838d9545cb2
User & Date: drh 2016-02-22 20:52:26.579
Context
2016-02-22
21:19
Clearer presentation of the logic. No functional changes. (Closed-Leaf check-in: a3dcf6db76 user: drh tags: skip-scan-improvement)
20:52
Avoid an unnecessary seek operation on some corner-case skip-scans. (check-in: 38e837e605 user: drh tags: skip-scan-improvement)
16:04
Always use the sqlite3VdbeDeleteAuxdata() routine for clearing auxdata on function parameter, rather than having a separate deleteAuxdataFromFrame() for doing the job for trigger frames. (check-in: 64386fa339 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
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);

    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 );
    VdbeCoverageIf(v, op==OP_SeekGE);  testcase( op==OP_SeekGE );
    VdbeCoverageIf(v, op==OP_SeekLE);  testcase( op==OP_SeekLE );
    VdbeCoverageIf(v, op==OP_SeekLT);  testcase( op==OP_SeekLT );


    /* Load the value for the inequality constraint at the end of the
    ** range (if any).
    */
    nConstraint = nEq;
    if( pRangeEnd ){
      Expr *pRight = pRangeEnd->pExpr->pRight;
      sqlite3ExprCacheRemove(pParse, regBase+nEq, 1);








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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 );
      VdbeCoverageIf(v, op==OP_SeekGE);  testcase( op==OP_SeekGE );
      VdbeCoverageIf(v, op==OP_SeekLE);  testcase( op==OP_SeekLE );
      VdbeCoverageIf(v, op==OP_SeekLT);  testcase( op==OP_SeekLT );
    }
    
    /* Load the value for the inequality constraint at the end of the
    ** range (if any).
    */
    nConstraint = nEq;
    if( pRangeEnd ){
      Expr *pRight = pRangeEnd->pExpr->pRight;
      sqlite3ExprCacheRemove(pParse, regBase+nEq, 1);
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