Re: Hardware recommendations to scale to silly load
От | Matt Clark |
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Тема | Re: Hardware recommendations to scale to silly load |
Дата | |
Msg-id | OAEAKHEHCMLBLIDGAFELIEFFDHAA.matt@ymogen.net обсуждение исходный текст |
Ответ на | Re: Hardware recommendations to scale to silly load (Rod Taylor <rbt@rbt.ca>) |
Ответы |
Re: Hardware recommendations to scale to silly load
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Список | pgsql-performance |
> Ok.. I would be surprised if you needed much more actual CPU power. I > suspect they're mostly idle waiting on data -- especially with a Quad > Xeon (shared memory bus is it not?). In reality the CPUs get pegged: about 65% PG and 35% system. But I agree that memory throughput and latency is an issue. > Write performance won't matter very much. 3000 inserts/second isn't high > -- some additional battery backed write cache may be useful but not > overly important with enough ram to hold the complete dataset. I suspect > those are slow due to things like foreign keys -- which of course are > selects. 3000 inserts/sec isn't high when they're inside one transaction, but if each is inside its own transaction then that's 3000 commits/second. > case, additional ram will keep the system from hitting the disk for > writes as well. How does that work? > You may want to play around with checkpoints. Prevention of a checkpoint > during this hour will help prevent peaks. Be warned though, WAL will > grow very large, and recovery time should a crash occur could be > painful. Good point. I'll have a think about that.
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