Re: old synchronized scan patch
От | Florian G. Pflug |
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Тема | Re: old synchronized scan patch |
Дата | |
Msg-id | 4575881C.60206@phlo.org обсуждение исходный текст |
Ответ на | Re: old synchronized scan patch (Hannu Krosing <hannu@skype.net>) |
Ответы |
Re: old synchronized scan patch
Re: old synchronized scan patch |
Список | pgsql-hackers |
Hannu Krosing wrote: > The worst that can happen, is a hash collision, in which case you lose > the benefits of sync scans, but you wont degrade compared to non-sync > scans But it could cause "mysterious" performance regressions, no? Image that your app includes two large tables, which are both scannen frequently. Suppose that synchronous scanning gives this use-case a noticeable performance boost. Now, you dump and reload your schema, and suddently the hashes of oids of those tables collide. You percieve a noticeable drop in performance that you can neither explain nor fix without a rather deep understanding of postgres internals. greetings, Florian Pflug
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