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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2005-11-28 23:46:03 +0000 |
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| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2005-11-28 23:46:03 +0000 |
| commit | 4ab76b1c20500922aebfdd0c26aef4bdcc608e88 (patch) | |
| tree | 15520d91328e0773d59e68f756d6f60302b931b9 /src/backend/utils/adt/numutils.c | |
| parent | ee4aa3021e47584120a019b47859c11d196fba04 (diff) | |
| download | postgresql-4ab76b1c20500922aebfdd0c26aef4bdcc608e88.tar.gz postgresql-4ab76b1c20500922aebfdd0c26aef4bdcc608e88.zip | |
Tweak hash join code to use an additional heuristic for deciding whether
it's worth probing the outer relation for emptiness before building the
hash table. To wit, if we're rescanning a join previously performed,
remember whether we found it nonempty the previous time, and don't bother
with the probe if it was nonempty. This buys back the performance lost
in examples like Mario Weilguni's.
Diffstat (limited to 'src/backend/utils/adt/numutils.c')
0 files changed, 0 insertions, 0 deletions