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Reduce the number of cases where it is necessary to check for NULL after

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the loop terminating condition.

FossilOrigin-Name: 3c1ae447dec8fc2af1c5105134061717594ac0e0
This commit is contained in:
drh
2014-02-14 20:59:53 +00:00
parent 4a1d365903
commit f78da0e6af
3 changed files with 12 additions and 14 deletions
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12
src/where.c
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@@ -3134,17 +3134,15 @@ static Bitmask codeOneLoopStart(
sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
}
/* If there are inequality constraints, check that the value
** of the table column that the inequality contrains is not NULL.
** If it is, jump to the next iteration of the loop.
/* If there are inequality constraint upper bound but not a lower
** bound, then check that the value of the table column that the
** inequality contrains is not NULL since there is alway an implied
** lower bound of "column>NULL".
*/
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
if( (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==WHERE_TOP_LIMIT
&& (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));