Brian Fehrle <brianf@xxxxxxxxxxxxxxxxxxx> writes: > Hi all, need some help/clues on tracking down a performance issue. > PostgreSQL version: 8.3.11 > I've got a system that has 32 cores and 128 gigs of ram. We have > connection pooling set up, with about 100 - 200 persistent connections > open to the database. Our applications then use these connections to > query the database constantly, but when a connection isn't currently > executing a query, it's <IDLE>. On average, at any given time, there are > 3 - 6 connections that are actually executing a query, while the rest > are <IDLE>. > About once a day, queries that normally take just a few seconds slow way > down, and start to pile up, to the point where instead of just having > 3-6 queries running at any given time, we get 100 - 200. The whole > system comes to a crawl, and looking at top, the CPU usage is 99%. This is jumping to a conclusion based on insufficient data, but what you describe sounds a bit like the sinval queue contention problems that we fixed in 8.4. Some prior reports of that: http://archives.postgresql.org/pgsql-performance/2008-01/msg00001.php http://archives.postgresql.org/pgsql-performance/2010-06/msg00452.php If your symptoms match those, the best fix would be to update to 8.4.x or later, but a stopgap solution would be to cut down on the number of idle backends. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
