Re: nodeAgg perf tweak
От | Neil Conway |
---|---|
Тема | Re: nodeAgg perf tweak |
Дата | |
Msg-id | 1102040366.22124.244.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | Re: nodeAgg perf tweak (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-hackers |
On Thu, 2004-12-02 at 20:51 -0500, Tom Lane wrote: > No. The current code involves two pallocs per cycle, one inside the > aggregate function to construct its result value, and then one in > datumCopy to copy the result into the proper context. Ah, true -- missed the fact that PG_RETURN_INT64() does a palloc(). (We really ought to fix that on 64-bit machines...) > The fact that it's a central fix for all aggregate functions is > definitely a nice feature of your approach, but I am concerned about the > possible side-effects on user-defined aggregate functions that may not > work as you expect them to. I think it's safer to keep the aggregate > code behaving as-is and get the performance win in the individual > functions. There are not that many aggregates that we really care that > much about. Okay, fair enough :) BTW, the spec you posted in your previous message makes sense to me. -Neil
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