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Re: BUG #5611: SQL Function STABLE promoting to VOLATILE

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Brian Ceccarelli <bceccarelli(at)net32(dot)com>
Cc: "pgsql-bugs(at)postgresql(dot)org" <pgsql-bugs(at)postgresql(dot)org>
Subject: Re: BUG #5611: SQL Function STABLE promoting to VOLATILE
Date: 2010-08-11 15:18:26
Message-ID: 5912.1281539906@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-bugs
Brian Ceccarelli <bceccarelli(at)net32(dot)com> writes:
>      STABLE no longer means STABLE.  This behavior is killing my performance.  I am getting 500% to 30000% increase in latency.

You seem to be under the illusion that "stable" is a control knob for a
function result cache.  It is not, and never has been.  Postgres doesn't
do function result caching.

If you've constructed your app in such a way that it depends on not
inlining SQL set-returning functions, it's fairly easy to defeat that.
>From memory, marking a SRF as either strict or volatile will do it
(although volatile might cause you problems elsewhere --- I suspect
your design is pretty brittle in this area).

			regards, tom lane

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Subject: Re: BUG #5611: SQL Function STABLE promoting to VOLATILE
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Subject: Re: BUG #5612: Database Integrity

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