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Overview
| Comment: | Revise the VDBE comments for NULL-scan so that they also work make sense when reading a NULLS FIRST plan. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | nulls-last |
| Files: | files | file ages | folders |
| SHA3-256: |
bfe793780fa6fc7a1e7d0ee60606dda2 |
| User & Date: | drh 2019-08-23 17:09:02 |
Context
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2019-08-23
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| 20:33 | Move some things in parse.y so that TK_COLUMN and TK_AGG_COLUMN are assigned the same values as they are on trunk for a very small speedup. check-in: d26fdfa3 user: dan tags: nulls-last | |
| 17:09 | Revise the VDBE comments for NULL-scan so that they also work make sense when reading a NULLS FIRST plan. check-in: bfe79378 user: drh tags: nulls-last | |
| 17:00 | Additional simplifications of the WHERE loop code generator logic for NULLS LAST. check-in: 1383680d user: drh tags: nulls-last | |
Changes
Changes to src/wherecode.c.
1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 .... 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 .... 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 |
** so no further seeking is needed */
}else{
if( pLoop->wsFlags & WHERE_IN_EARLYOUT ){
sqlite3VdbeAddOp1(v, OP_SeekHit, iIdxCur);
}
if( regBignull ){
sqlite3VdbeAddOp2(v, OP_Integer, 1, regBignull);
VdbeComment((v, "NULL-scan needed flag"));
}
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 );
................................................................................
pLevel->p2 = sqlite3VdbeCurrentAddr(v);
/* 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);
}
op = aEndOp[bRev*2 + endEq];
sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
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 );
................................................................................
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);
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 );
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1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 .... 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 .... 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 |
** so no further seeking is needed */
}else{
if( pLoop->wsFlags & WHERE_IN_EARLYOUT ){
sqlite3VdbeAddOp1(v, OP_SeekHit, iIdxCur);
}
if( regBignull ){
sqlite3VdbeAddOp2(v, OP_Integer, 1, regBignull);
VdbeComment((v, "NULL-scan pass ctr"));
}
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 );
................................................................................
pLevel->p2 = sqlite3VdbeCurrentAddr(v);
/* 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 2nd pass"));
VdbeCoverage(v);
}
op = aEndOp[bRev*2 + endEq];
sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
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 );
................................................................................
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 1st pass"));
VdbeCoverage(v);
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 );
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