From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | "Tambet Matiisen" <t(dot)matiisen(at)aprote(dot)ee> |
Cc: | "Neil Conway" <neilc(at)samurai(dot)com>, pgsql-performance(at)postgresql(dot)org |
Subject: | Re: SQL function inlining (was: View vs function) |
Date: | 2005-03-23 16:55:28 |
Message-ID: | 7635.1111596928@sss.pgh.pa.us |
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Lists: | pgsql-performance |
"Tambet Matiisen" <t(dot)matiisen(at)aprote(dot)ee> writes:
> I observed slowdowns when I declared SQL function as strict. There were
> no slowdowns, when I implmented the same function in plpgsql, in fact it
> got faster with strict, if parameters where NULL. Could it be
> side-effect of SQL function inlining? Is there CASE added around the
> function to not calculate it, when one of the parameters is NULL?
IIRC we will not inline a STRICT SQL function if the resulting
expression would not behave strict-ly. This is clearly a necessary rule
because inlining would change the behavior otherwise. But the test for
it is pretty simplistic: CASEs are considered not strict, period. So I
think you are measuring the difference between inlined and not-inlined.
I'd suggest just leaving off the STRICT if you are writing a SQL
function you hope to have inlined.
regards, tom lane
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