diff options
author | Tom Lane <tgl@sss.pgh.pa.us> | 2005-01-28 20:35:14 +0000 |
---|---|---|
committer | Tom Lane <tgl@sss.pgh.pa.us> | 2005-01-28 20:35:14 +0000 |
commit | 7c67dcacd83c885618a58936df627a17470d9991 (patch) | |
tree | 759f3d24900f14b55cd260b5ef8bddc8fa22df2b /src/backend/utils/adt/regexp.c | |
parent | a098f533d15efe5552c0b6cd661cc123231c8c54 (diff) | |
download | postgresql-7c67dcacd83c885618a58936df627a17470d9991.tar.gz postgresql-7c67dcacd83c885618a58936df627a17470d9991.zip |
When dealing with multiple grouping columns coming from the same table,
clamp the estimated number of groups to table row count over 10, instead
of table row count; this reflects a heuristic that people probably won't
group over a near-unique set of columns, and the knowledge that we don't
currently have any way to estimate the correlation of the columns better
than guessing. This change creates a trivial plan change in one of the
regression tests.
Diffstat (limited to 'src/backend/utils/adt/regexp.c')
0 files changed, 0 insertions, 0 deletions