Re: Avg performance for int8/numeric
От | Neil Conway |
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Тема | Re: Avg performance for int8/numeric |
Дата | |
Msg-id | 1164341365.23622.191.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | Avg performance for int8/numeric (Mark Kirkwood <markir@paradise.net.nz>) |
Ответы |
Re: Avg performance for int8/numeric
Re: Avg performance for int8/numeric Re: Avg performance for int8/numeric |
Список | pgsql-patches |
On Fri, 2006-11-24 at 11:08 +1300, Mark Kirkwood wrote: > - Modifies do_numeric_accum to have an extra bool parameter and does not > calc sumX2 when it is false. I think it would be clearer to reorganize this function slightly, and have only a single branch on "useSumX2". On first glance it isn't obviously that transdatums[2] is defined (but unchanged) when useSumX2 is false. > Performance gain is approx 33% Nice. > (it is still slower than doing sum/count - possibly due to the > construct/deconstruct overhead of the numeric transition array). This would indeed be worth profiling. If it turns out that array overhead is significant, I wonder if we could use a composite type for the transition variable instead. That might also make it easier to represent the "N" value as an int8 rather than a numeric. -Neil
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