Re: Checkpoint question
От | Jim C. Nasby |
---|---|
Тема | Re: Checkpoint question |
Дата | |
Msg-id | 20060113184025.GI9017@pervasive.com обсуждение исходный текст |
Ответ на | Re: Checkpoint question (Qingqing Zhou <zhouqq@cs.toronto.edu>) |
Список | pgsql-hackers |
On Thu, Jan 12, 2006 at 05:00:49PM -0500, Qingqing Zhou wrote: > > > On Thu, 12 Jan 2006, Jim C. Nasby wrote: > > > > > It sounds like worrying about this would be much more interesting on a > > machine that is seeing both a fairly heavy IO load (meaning checkpoint > > will both take longer and affect other workloads more) and is seeing a > > pretty high rate of buffer updates (meaning that we'd likely do a bunch > > of extra work as part of the checkpoint if we didn't take note of > > exactly what buffers needed to be flushed). Unfortunately I don't think > > there's any way for the backend to know much about either condition > > right now, so it couldn't decide when it made sense to make a list of > > buffers to flush. Maybe in the future... > > > > The senario you mentioned is happened in many OLTP applications. No need > for backend to know this -- we can leave the decision to the DBA: > CHECKPOINT FULL or CHECPOINT PARTIAL. If you got some machines can observe > its CHECKPOINT duration, that would be sweet. Maybe I'm missing something here, but wouldn't that only help if you were manually issuing checkpoints? -- Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
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