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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2003-02-15 20:12:41 +0000 |
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| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2003-02-15 20:12:41 +0000 |
| commit | 056467ec6bcbd81a9d1480af8d641946a5ef1bff (patch) | |
| tree | 9bcbdc5f6443cc045783a0e712fbab572eff0952 /src/backend/parser/parse_expr.c | |
| parent | 50c4190e370a66bc8c52a0985cebf5560b28b058 (diff) | |
| download | postgresql-056467ec6bcbd81a9d1480af8d641946a5ef1bff.tar.gz postgresql-056467ec6bcbd81a9d1480af8d641946a5ef1bff.zip | |
Teach planner how to propagate pathkeys from sub-SELECTs in FROM up to
the outer query. (The implementation is a bit klugy, but it would take
nontrivial restructuring to make it nicer, which this is probably not
worth.) This avoids unnecessary sort steps in examples like
SELECT foo,count(*) FROM (SELECT ... ORDER BY foo,bar) sub GROUP BY foo
which means there is now a reasonable technique for controlling the
order of inputs to custom aggregates, even in the grouping case.
Diffstat (limited to 'src/backend/parser/parse_expr.c')
0 files changed, 0 insertions, 0 deletions