On Fri, 2008-09-05 at 11:21 -0700, Tom Raney wrote: > Why does the planner consider both input variations of each symmetric merge > join? The README says "there is not a lot of difference" between the two > options. When are there any differences? > > -Tom Raney >
http://archives.postgresql.org/pgsql-general/2008-08/msg00967.php My understanding from that thread is that if one table has high ndistinct and the other has low ndistinct, one plan may require more re-scanning than the other. Regards, Jeff Davis -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
