From: | Craig Ringer <craig(at)postnewspapers(dot)com(dot)au> |
---|---|
To: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Josip Rodin <joy(at)entuzijast(dot)net>, pgsql-general(at)postgresql(dot)org |
Subject: | Re: simple functions, huge overhead, no cache |
Date: | 2010-07-12 06:06:43 |
Message-ID: | 4C3AB0F3.9060205@postnewspapers.com.au |
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Lists: | pgsql-general |
On 11/07/2010 5:46 AM, Pavel Stehule wrote:
> any using a non simple expression is very slow - so there can be some
> a warning when people use it. Sometimes people don't know (me too),
> when use expensive expression
>
> for example
>
> rowvar := (10,20)
>
> it isn't simple - I am not sure, if it is true still.
Rather than warning whenever the SPI is invoked from PL/PgSQL, perhaps
this would be a task better suited for inclusion in a profiler feature
for the PL/PgSQL debugger?
I'm not particularly interested in the notion myself, but I don't think
warnings about "non-simple" statements would be very helpful. You'd be
drowned in warnings for statements that were a necessary part of the
operation of your functions, things for which there was no other way to
do it.
It seems like a profiler, which is designed to filter and organize the
collected data, and which can be attached only to specific functions
that you want to know about, might be a better job. As there's already a
PL/PgSQL debugger, some of the infrastructure required is already present.
Meh, personally I'll stick to the good old profiling methods "is it fast
enough", "\timing", and "explain analyze".
--
Craig Ringer
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