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author | Tom Lane <tgl@sss.pgh.pa.us> | 2006-06-07 17:08:15 +0000 |
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committer | Tom Lane <tgl@sss.pgh.pa.us> | 2006-06-07 17:08:15 +0000 |
commit | 735529ce2429a033074537e5e48250fc5bc07a39 (patch) | |
tree | 2623d357e7c1a37181330d492df9c20b2c8d15c2 /src/tutorial/funcs_new.c | |
parent | c944851a791d8d43ea1918ab766fe0e7e93a48d0 (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/tutorial/funcs_new.c')
0 files changed, 0 insertions, 0 deletions