Richard Kojedzinszky <krichy@xxxxxxxxxxxx> writes: > Dear list, > We have a database schema, which looks the same as the attached script. > When filling the tables with data, and skipping analyze on the table (so > pg_stats contains no records for table 'a'), the first select in the > script runs fast, but after an analyze the planner decides to sequence > scan tables b and c, thus making the query much slower. Can somebody help > me solving this issue, or tuning our installation to not to use sequence > scans in this case? Um ... did you analyze all the tables, or just some of them? I get sub-millisecond runtimes if all four tables have been analyzed, but it does seem to pick lousy plans if, say, only a and b have been analyzed. What you really need for this query structure is the parameterized-path work I've been doing for 9.2; but at least on the exact example given, I'm not seeing that 9.1 is that much worse. 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
