| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> |
| Cc: | Rob Sargent <robjsargent(at)gmail(dot)com>, "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: query not scaling |
| Date: | 2017-10-26 15:01:27 |
| Message-ID: | 30441.1509030087@sss.pgh.pa.us |
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| Lists: | pgsql-general |
Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> writes:
> Also, to have PostgreSQL inline the function, which would be good
> for performance, it should be declared IMMUTABLE.
Actually, if you hope to have a SQL function be inlined, it's better
not to decorate it at all --- not with IMMUTABLE, and not with STRICT
either. Both of those restrict the parser's ability to inline unless
it can prove the contained expression is equally immutable/strict.
With the default attributes of volatile/not strict, there's nothing
to prove.
(In any case, it's usually easy enough to tell from EXPLAIN output
whether inlining has happened.)
regards, tom lane
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