On Dec 5, 2007 9:49 PM, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > 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... 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? I can disable the process, but if the backup takes an hour that's an hour where all the data in this table is stale. I believe we chose to do it this way, because we wanted to minimize the amount of time the table wasn't available, which is why we didn't use a truncate based strategy. Thanks, Bryan ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
