Josh Berkus <josh@xxxxxxxxxxxx> writes: > On 03/06/2013 06:54 AM, David Leverton wrote: >> I'm encountering very poor query plans when joining against a union, > Actually, in case #4, Postgres *is* pushing down the join qual into the > segments of the Union. Yeah, but not further. I believe the core issue here (as of 9.2) is that we're not willing to generate parameterized paths for subquery relations. We could do that without a huge amount of new code, I think, but the scary thing is how much time it might take to generate (and then discard most of the) plans for assorted parameterizations of complicated subqueries. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
