Re: Hardware/OS recommendations for large databases (
От | Mark Kirkwood |
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Тема | Re: Hardware/OS recommendations for large databases ( |
Дата | |
Msg-id | 437F9919.20305@paradise.net.nz обсуждение исходный текст |
Ответ на | Re: Hardware/OS recommendations for large databases ( ("Luke Lonergan" <llonergan@greenplum.com>) |
Ответы |
Re: Hardware/OS recommendations for large databases (
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Список | pgsql-performance |
Luke Lonergan wrote: > Mark, > > On 11/18/05 3:46 PM, "Mark Kirkwood" <markir@paradise.net.nz> wrote: > > >>If you alter this to involve more complex joins (e.g 4. way star) and >>(maybe add a small number of concurrent executors too) - is it still the >>case? > > > 4-way star, same result, that's part of my point. With Bizgres MPP, the > 4-way star uses 4 concurrent scanners, though not all are active all the > time. And that's per segment instance - we normally use one segment > instance per CPU, so our concurrency is NCPUs plus some. > Luke - I don't think I was clear enough about what I was asking, sorry. I added the more "complex joins" comment because: - I am happy that seqscan is cpu bound after ~110M/s (It's cpu bound on my old P3 system even earlier than that....) - I am curious if the *other* access methods (indexscan, nested loop, hash, merge, bitmap) also suffer then same fate. I'm guessing from your comment that you have tested this too, but I think its worth clarifying! With respect to Bizgres MPP, scan parallelism is a great addition... very nice! (BTW - is that in 0.8, or are we talking a new product variant?) regards Mark
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