Re: nodeAgg perf tweak
От | Neil Conway |
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Тема | Re: nodeAgg perf tweak |
Дата | |
Msg-id | 1102038280.22124.232.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | Re: nodeAgg perf tweak (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: nodeAgg perf tweak
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Список | pgsql-hackers |
On Thu, 2004-12-02 at 19:07 -0500, Tom Lane wrote: > True, but you still have to palloc if it returns the second argument. Is that common? In any case, I don't see how you can _ever_ avoid a palloc if the aggregate returns the second argument. The second argument is in a per-tuple memory context: there's nothing the aggregate, or nodeAgg, can do about it. I think the tradeoffs between our patches are: - mine would apply to all aggregates, without the need to modify any of them individually - yours would mean that int8inc() and similar aggregates wouldn't ever need to do palloc(); mine would require a palloc() every k calls to the transition function. I don't really see this as a problem: in practice k will be sufficiently large that the palloc overhead should be negligible. -Neil
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