On Thu, Jun 7, 2012 at 5:07 PM, Jerry Sievers <gsievers19@xxxxxxxxxxx> wrote: > Lonni J Friedman <netllama@xxxxxxxxx> writes: > >> On Thu, Jun 7, 2012 at 12:40 PM, Magnus Hagander <magnus@xxxxxxxxxxxx> wrote: >> >>> On Thu, Jun 7, 2012 at 8:04 PM, Lonni J Friedman <netllama@xxxxxxxxx> wrote: >>>> On Thu, Jun 7, 2012 at 10:41 AM, Lonni J Friedman <netllama@xxxxxxxxx> wrote: >>>>> Greetings, >>>>> I have a 4 server postgresql-9.1.3 cluster (one master doing streaming >>>>> replication to 3 hot standby servers). All of them are running >>>>> Fedora-16-x86_64. >>>>> >>>>> http://wiki.postgresql.org/wiki/Lock_Monitoring >>>> >>>> err, i included that URL but neglected to explain why. On a different >>>> list someone suggested that I verify that there were no locks that >>>> were blocking things, and I did so, and found no locks. >>>> >>>> So I'm still at a loss why pg_basebackup is killing perf, and would >>>> appreciate pointers on how to debug it or at least reduce its impact >>>> on performance if that is possible. >>>> >>> >>> My guess would be that you are overloading your I/O system. You should >>> look at values from iostat and vmstat from when the system works fine >>> and when you run pg_basebackup, that should give you a hint in the >>> right direction. >> >> ok, thanks. i'll take a look at that. If this turns out to be the >> issue, is there some way to get pg_basebackup to run more slowly, so >> that it has less impact? Or could I do this with ionice on the >> pg_basebackup process? > > You might try stopping pg_basebackup in place with SIGSTOP and check > if problem goes away. SIGCONT and you should start having > sluggishness again. > > If verified, then any sort of throttling mechanism should work. I'm certain that the problem is triggered only when pg_basebackup is running. Its very predictable, and goes away as soon as pg_basebackup finishes running. What do you mean by a throttling mechanism? -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
