I know the idea has come up a few times to do cross-column statistics to improve plans when the data distributions are dependent. I found a couple references in the archives:
http://archives.postgresql.org/pgsql-hackers/2006-09/msg02118.php http://archives.postgresql.org/pgsql-hackers/2006-08/msg00924.php We can already keep stats for a functional index. Is there a reason we can't keep stats for a multi-column index? Out of the two situations outlined by Jim Nasby here: http://archives.postgresql.org/pgsql-hackers/2006-08/msg00948.php It would not help with joins, but it would help with columns that are referred to as a group (e.g. a=1 AND b<20). Regards, Jeff Davis ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
