=?KOI8-U?B?96bUwcymyiD0yc3eydvJzg==?= <tivv00@xxxxxxxxx> writes: > I've thought and someone in this list've told me that this should be done > automatically. No, that's not true. We do make deductions about transitive equalities, ie, given WHERE a=b AND b=c the planner will infer a=c and use that if it's helpful. We don't make deductions about inequalities such as a>c. In theory there's enough information available to do so, but overall trying to do that would probably waste more cycles than it would save. You'd need a lot of expensive new planner infrastructure, and in the vast majority of queries it wouldn't produce anything very helpful. As was pointed out, even if we had such logic it wouldn't apply in this example, because the equality conditions aren't real equalities but OUTER JOIN conditions. 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
