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Overview
Comment:Avoid unnecessary OP_IfNull checks when doing a range query where there is a constraint on the lower bound of the range.
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SHA1: de08a7e7abbad9b94d0268d096ef4555d31c8b0c
User & Date: drh 2013-11-16 14:03:53
Context
2013-11-16
15:35
Fully constraint the ORDER BY on the top-10 line of the --summary output from the wordcount test program. Add the run-wordcount.bash script for running wordcount in various configurations. check-in: 7edf39eb user: drh tags: trunk
14:03
Avoid unnecessary OP_IfNull checks when doing a range query where there is a constraint on the lower bound of the range. check-in: de08a7e7 user: drh tags: trunk
13:55
Simplification and performance improvement to the logic that factors constant expressions ouf of inner loops. check-in: ee9353fd user: drh tags: trunk
Changes
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Changes to src/where.c.

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    */
    r1 = sqlite3GetTempReg(pParse);
    testcase( pLoop->wsFlags & WHERE_BTM_LIMIT );
    testcase( pLoop->wsFlags & WHERE_TOP_LIMIT );
    if( (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 
     && (j = pIdx->aiColumn[nEq])>=0 
     && pIdx->pTable->aCol[j].notNull==0 

    ){
      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, nEq, r1);
      VdbeComment((v, "%s", pIdx->pTable->aCol[j].zName));
      sqlite3VdbeAddOp2(v, OP_IsNull, r1, addrCont);
    }
    sqlite3ReleaseTempReg(pParse, r1);








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3139
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    */
    r1 = sqlite3GetTempReg(pParse);
    testcase( pLoop->wsFlags & WHERE_BTM_LIMIT );
    testcase( pLoop->wsFlags & WHERE_TOP_LIMIT );
    if( (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 
     && (j = pIdx->aiColumn[nEq])>=0 
     && pIdx->pTable->aCol[j].notNull==0 
     && (nEq || (pLoop->wsFlags & WHERE_BTM_LIMIT)==0)
    ){
      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, nEq, r1);
      VdbeComment((v, "%s", pIdx->pTable->aCol[j].zName));
      sqlite3VdbeAddOp2(v, OP_IsNull, r1, addrCont);
    }
    sqlite3ReleaseTempReg(pParse, r1);