"Bryan Murphy" <bryan.murphy@gmail.com> writes: > When we run pg_dump on our database, our web site becomes completely > unresponsive. ... > Does pg_dump create table locks? It doesn't look like an I/O problem > as far as I can tell... Only access-share locks, but that could still be an issue if anything in your system likes to take exclusive locks. Have you looked into pg_locks to see if anything's getting blocked? pg_dump is entirely capable of causing an unpleasant amount of I/O load, but that shouldn't result in "complete unresponsiveness", and anyway your iostat output doesn't look like you're saturated... regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org/

"Bryan Murphy" <bryan.murphy@gmail.com> writes: > It does appear to be lock contention. I took a closer look this > morning, and I noticed our web site was consistently locking up on a > particular table, and there were a number of exclusive locks. I > started eliminating various jobs, and found the one that essentially > rewrites that particular table every 5 minutes to be the culprit > (create new table, drop old table, rename new table). > Is there a better way we can do this so that we won't causes lock > contention during a dump? Why dump such a table at all? It evidently doesn't contain any data you need to preserve ... I forget which version you are running, but 8.2 pg_dump has an --exclude-table switch which'd work peachy for this. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq