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Overview
| Comment: | Set the NULLEQ flag on the sequence counter comparison in the ORDER BY LIMIT optimization, to avoid coverage complaints about not testing the NULL case. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | orderby-limit |
| Files: | files | file ages | folders |
| SHA1: |
ed1b30dc932a7c03e173b130c5f55f99 |
| User & Date: | drh 2016-05-20 13:44:58 |
Context
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2016-05-20
| ||
| 14:11 | For queries with both ORDER BY and LIMIT, if the rows of the inner loop are emitted in ORDER BY order and the LIMIT has been reached, then optimize by exiting the inner loop and continuing with the next cycle of the first outer loop. check-in: 559733b0 user: drh tags: trunk | |
| 13:44 | Set the NULLEQ flag on the sequence counter comparison in the ORDER BY LIMIT optimization, to avoid coverage complaints about not testing the NULL case. Closed-Leaf check-in: ed1b30dc user: drh tags: orderby-limit | |
| 00:21 | A few simple test cases for the ORDER BY LIMIT optimization. check-in: 08849eab user: drh tags: orderby-limit | |
Changes
Changes to src/select.c.
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/* If the inner loop is driven by an index such that values from
** the same iteration of the inner loop are in sorted order, then
** immediately jump to the next iteration of an inner loop if the
** entry from the current iteration does not fit into the top
** LIMIT+OFFSET entries of the sorter. */
int iBrk = sqlite3VdbeCurrentAddr(v) + 2;
sqlite3VdbeAddOp3(v, OP_Eq, regBase+nExpr, iBrk, r1);
VdbeCoverage(v);
}
sqlite3VdbeJumpHere(v, addr);
}
}
/*
|
> |
607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 |
/* If the inner loop is driven by an index such that values from
** the same iteration of the inner loop are in sorted order, then
** immediately jump to the next iteration of an inner loop if the
** entry from the current iteration does not fit into the top
** LIMIT+OFFSET entries of the sorter. */
int iBrk = sqlite3VdbeCurrentAddr(v) + 2;
sqlite3VdbeAddOp3(v, OP_Eq, regBase+nExpr, iBrk, r1);
sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
VdbeCoverage(v);
}
sqlite3VdbeJumpHere(v, addr);
}
}
/*
|