Benjamin Minshall <minshall@xxxxxxxxxxxxxx> writes: > Tom Lane wrote: >> It's sounding like what you had was just transient bloat, in which case >> it might be useful to inquire whether anything out-of-the-ordinary had >> been done to the database right before the excessive-CPU-usage problem >> started. > I don't believe that there was any unusual activity on the server, but I > have set up some more detailed logging to hopefully identify a pattern > if the problem resurfaces. A further report led us to realize that 8.2.x in fact has a nasty bug here: the stats collector is supposed to dump its stats to a file at most every 500 milliseconds, but the code was actually waiting only 500 microseconds :-(. The larger the stats file, the more obvious this problem gets. If you want to patch this before 8.2.4, try this... Index: pgstat.c =================================================================== RCS file: /cvsroot/pgsql/src/backend/postmaster/pgstat.c,v retrieving revision 1.140.2.2 diff -c -r1.140.2.2 pgstat.c *** pgstat.c 26 Jan 2007 20:07:01 -0000 1.140.2.2 --- pgstat.c 1 Mar 2007 20:04:50 -0000 *************** *** 1689,1695 **** /* Preset the delay between status file writes */ MemSet(&write_timeout, 0, sizeof(struct itimerval)); write_timeout.it_value.tv_sec = PGSTAT_STAT_INTERVAL / 1000; ! write_timeout.it_value.tv_usec = PGSTAT_STAT_INTERVAL % 1000; /* * Read in an existing statistics stats file or initialize the stats to --- 1689,1695 ---- /* Preset the delay between status file writes */ MemSet(&write_timeout, 0, sizeof(struct itimerval)); write_timeout.it_value.tv_sec = PGSTAT_STAT_INTERVAL / 1000; ! write_timeout.it_value.tv_usec = (PGSTAT_STAT_INTERVAL % 1000) * 1000; /* * Read in an existing statistics stats file or initialize the stats to regards, tom lane
