Re: simple functions, huge overhead, no cache - Mailing list pgsql-general

From Josip Rodin
Subject Re: simple functions, huge overhead, no cache
Date
Msg-id 20100712171508.GA701@orion.carnet.hr
Whole thread Raw
In response to Re: simple functions, huge overhead, no cache  (Pavel Stehule <pavel.stehule@gmail.com>)
Responses Re: simple functions, huge overhead, no cache  (Pavel Stehule <pavel.stehule@gmail.com>)
List pgsql-general
On Mon, Jul 12, 2010 at 04:38:48PM +0200, Pavel Stehule wrote:
> 2010/7/12 Josip Rodin <joy@entuzijast.net>:
> > On Mon, Jul 12, 2010 at 02:06:43PM +0800, Craig Ringer wrote:
> >> Meh, personally I'll stick to the good old profiling methods "is it fast
> >> enough", "\timing", and "explain analyze".
> >
> > I agree. Some hint could be included in 'explain analyze' output, maybe just
> > to separate the timings for things that are well covered by the query plan
> > optimizer from those that aren't. I found this in a line like this:
>
> it is useles for functions - explain doesn't show lines of executed
> functions. Can you show some example of some more complex query.

It doesn't have to show me any lines, but it could tell me which part of
the query is actually being optimized, and OTOH which part is simply being
executed N times unconditionally because it's a function that is marked as
volatile. That alone would be a reasonable improvement.

--
     2. That which causes joy or happiness.

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