Re: Hot standby having high requested checkpoints?
От | Brian Fehrle |
---|---|
Тема | Re: Hot standby having high requested checkpoints? |
Дата | |
Msg-id | 4F592FA1.6060005@consistentstate.com обсуждение исходный текст |
Ответ на | Re: Hot standby having high requested checkpoints? (Brian Fehrle <brianf@consistentstate.com>) |
Список | pgsql-admin |
Anyone have any thoughts on why this may be happening? thanks, - Brian F On 03/01/2012 04:38 PM, Brian Fehrle wrote: > I just now ran the following query a few times after each other on the > hot standby: > > select now(), * from pg_stat_bgwriter; > > Here are the results: > > now | checkpoints_timed | checkpoints_req | > buffers_checkpoint | buffers_clean | maxwritten_clean | > buffers_backend | buffers_alloc > -------------------------------+-------------------+-----------------+--------------------+---------------+------------------+-----------------+--------------- > > 2012-03-01 23:24:49.099194+00 | 11546 | 145300 > | 1000409459 | 38483026 | 170724 | > 5058186 | 438703950 > 2012-03-01 23:24:52.139176+00 | 11546 | 145300 > | 1000409459 | 38483027 | 170724 | > 5058191 | 438703975 > 2012-03-01 23:24:59.129171+00 | 11546 | 145302 > | 1000409459 | 38483081 | 170724 | > 5058214 | 438704438 > 2012-03-01 23:25:05.957532+00 | 11546 | 145304 > | 1000409459 | 38483118 | 170724 | > 5058230 | 438704689 > 2012-03-01 23:25:09.519175+00 | 11546 | 145305 > | 1000409459 | 38483160 | 170724 | > 5058239 | 438704968 > 2012-03-01 23:25:37.019194+00 | 11546 | 145308 > | 1000409459 | 38483259 | 170724 | > 5058255 | 438705566 > 2012-03-01 23:25:40.659164+00 | 11546 | 145308 > | 1000409459 | 38483268 | 170724 | > 5058257 | 438705639 > 2012-03-01 23:25:47.239281+00 | 11546 | 145309 > | 1000409459 | 38483283 | 170724 | > 5058266 | 438705815 > 2012-03-01 23:26:23.858716+00 | 11546 | 145312 > | 1000409459 | 38483393 | 170724 | > 5058307 | 438706561 > 2012-03-01 23:26:46.467493+00 | 11546 | 145317 > | 1000409670 | 38483524 | 170724 | > 5058354 | 438707619 > > in two minutes, I saw 17 checkpoints_req, and the number of > buffers_checkpoint didn't budge till the last few and even then not much. > > checkpoint_segments = 256 > > - Brian F > > On 03/01/2012 01:35 AM, Simon Riggs wrote: >> On Tue, Feb 28, 2012 at 10:53 PM, Brian Fehrle >> <brianf@consistentstate.com> wrote: >> >>> I have two PostgreSQL 9.0.5 clusters, one is a master and the other >>> is a hot >>> standby via streaming replication. I'm monitoring some stats on each >>> and I'm >>> noticing something very odd. On the master, I get between 2 and 4 >>> requested >>> checkpoints per hour, but on the hot standby I'm seeing between 200 >>> and 300 >>> requested checkpoints per hour. >> We don't do a restartpoint on the standby unless we see a checkpoint >> record, so that result should be impossible. >> >> So I'm guessing you're reading the stats wrong? >> > >
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