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Additional simplifications of the WHERE loop code generator logic for

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NULLS LAST.

FossilOrigin-Name: 1383680d927d7d703933be7653c0019199845e7f7e82bcc76d9ca3808093e9d8
This commit is contained in:
drh
2019-08-23 17:00:22 +00:00
parent 0086e07865
commit 5f6a4ea2e2
3 changed files with 21 additions and 21 deletions
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28
src/wherecode.c
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@@ -1708,6 +1708,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
assert( bSeekPastNull==0 || bStopAtNull==0 );
if( regBignull ){
assert( bSeekPastNull==1 || bStopAtNull==1 );
assert( bSeekPastNull==!bStopAtNull );
assert( bStopAtNull==startEq );
sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+2);
op = aStartOp[(nConstraint>1)*4 + 2 + bRev];
@@ -1766,6 +1767,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
/* Check if the index cursor is past the end of the range. */
if( nConstraint ){
if( regBignull ){
/* Except, skip the end-of-range check while doing the NULL-scan */
sqlite3VdbeAddOp2(v, OP_IfNot, regBignull, sqlite3VdbeCurrentAddr(v)+3);
VdbeComment((v, "If NULL-scan active"));
VdbeCoverage(v);
@@ -1778,23 +1780,21 @@ Bitmask sqlite3WhereCodeOneLoopStart(
testcase( op==OP_IdxLE ); VdbeCoverageIf(v, op==OP_IdxLE );
}
if( regBignull ){
/* During a NULL-scan, check to see if we have reached the end of
** the NULLs */
assert( bSeekPastNull==!bStopAtNull );
assert( bSeekPastNull+bStopAtNull==1 );
assert( nConstraint+bSeekPastNull>0 );
sqlite3VdbeAddOp2(v, OP_If, regBignull, sqlite3VdbeCurrentAddr(v)+2);
VdbeComment((v, "If NULL-scan pending"));
VdbeCoverage(v);
if( bStopAtNull ){
op = aEndOp[bRev*2 + 0];
assert( op==OP_IdxGE || op==OP_IdxLE );
sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
testcase( op==OP_IdxGE ); VdbeCoverageIf(v, op==OP_IdxGE );
testcase( op==OP_IdxLE ); VdbeCoverageIf(v, op==OP_IdxLE );
}else{
op = aEndOp[bRev*2 + endEq];
sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint+1);
testcase( op==OP_IdxGT ); VdbeCoverageIf(v, op==OP_IdxGT );
testcase( op==OP_IdxGE ); VdbeCoverageIf(v, op==OP_IdxGE );
testcase( op==OP_IdxLT ); VdbeCoverageIf(v, op==OP_IdxLT );
testcase( op==OP_IdxLE ); VdbeCoverageIf(v, op==OP_IdxLE );
}
op = aEndOp[bRev*2 + bSeekPastNull];
sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase,
nConstraint+bSeekPastNull);
testcase( op==OP_IdxGT ); VdbeCoverageIf(v, op==OP_IdxGT );
testcase( op==OP_IdxGE ); VdbeCoverageIf(v, op==OP_IdxGE );
testcase( op==OP_IdxLT ); VdbeCoverageIf(v, op==OP_IdxLT );
testcase( op==OP_IdxLE ); VdbeCoverageIf(v, op==OP_IdxLE );
}
if( pLoop->wsFlags & WHERE_IN_EARLYOUT ){