| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Hadi Moshayedi <hadi(at)moshayedi(dot)net> |
| Cc: | Kevin Grittner <kgrittn(at)ymail(dot)com>, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, "mark(dot)kirkwood(at)catalyst(dot)net(dot)nz" <mark(dot)kirkwood(at)catalyst(dot)net(dot)nz> |
| Subject: | Re: Improving avg performance for numeric |
| Date: | 2013-03-19 16:45:48 |
| Message-ID: | 6577.1363711548@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
[ please do not top-reply ]
Hadi Moshayedi <hadi(at)moshayedi(dot)net> writes:
> On Tue, Mar 19, 2013 at 6:25 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Uh, what? Fooling around with the implementation of avg() should surely
>> not change any planning decisions.
> I am not sure how this works, but I also changed numeric sum(), and the
> views in question had a numeric sum() column. Can that have any impact?
[ looks at patch... ] Oh, I see what's affecting the plan: you changed
the aggtranstypes to internal for a bunch of aggregates. That's not
very good, because right now the planner takes that to mean that the
aggregate could eat a lot of space. We don't want that to happen for
these aggregates, I think.
regards, tom lane
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