"Anne Rosset" <arosset@xxxxxxxxxx> wrote: > We are running some performances tests. With a lot of concurrent > access, queries get very slow. When there is no load, those > queries run fast. What's "a lot"? > We kind of see a trend about these queries: it seems like the > ones that become very slow have an ORDER BY or MAX in them. Without knowing the PostgreSQL version or more details about the queries, I would only be guessing at the cause. > It seems to me that we should try increasing shared_buffers. But > do you have any other suggestions? Or do you see anything wrong in > our config? I don't think you showed us your whole PostgreSQL configuration, and the format was hard to read -- it's best to show the contents of your postgresql.conf file, minus comments. If you read this page and re-post we can probably be more helpful: http://wiki.postgresql.org/wiki/SlowQueryQuestions -Kevin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance