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author | Tom Lane <tgl@sss.pgh.pa.us> | 2006-06-07 17:08:07 +0000 |
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committer | Tom Lane <tgl@sss.pgh.pa.us> | 2006-06-07 17:08:07 +0000 |
commit | ae0c8d09fb05d39c4f2c548bfc4720dadbd83532 (patch) | |
tree | 41c52c469cf75c5207158592862ac6fb95f8957a /src/backend/executor/nodeAppend.c | |
parent | ca9d50304ff664ec2fbf6ddf4cafe3d031c319cb (diff) |
Remove "fuzzy comparison" logic in qsort comparison function for
choose_bitmap_and(). It was way too fuzzy --- per comment, it was meant to be
1% relative difference, but was actually coded as 0.01 absolute difference,
thus causing selectivities of say 0.001 and 0.000000000001 to be treated as
equal. I believe this thinko explains Maxim Boguk's recent complaint. While
we could change it to a relative test coded like compare_fuzzy_path_costs(),
there's a bigger problem here, which is that any fuzziness at all renders the
comparison function non-transitive, which could confuse qsort() to the point
of delivering completely wrong results. So forget the whole thing and just
do an exact comparison.
Diffstat (limited to 'src/backend/executor/nodeAppend.c')
0 files changed, 0 insertions, 0 deletions