Re: Interesting case of IMMUTABLE significantly hurting performance

From: Craig Ringer <craig(at)2ndquadrant(dot)com>
To: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Cc: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Interesting case of IMMUTABLE significantly hurting performance
Date: 2013-08-14 03:57:00
Message-ID: 520B000C.2030104@2ndquadrant.com
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On 08/14/2013 11:52 AM, Pavel Stehule wrote:
>
> If I understand, a used IMMUTABLE flag disables inlining. What you see,
> is SQL eval overflow.
>
> My rule is - don't use flags in SQL functions, when it is possible.

Interesting. I knew that was the case for STRICT, but am surprised to
hear it's the case for IMMUTABLE as well. That seems ...
counter-intuitive. Not to mention undocumented as far as I can see.

--
Craig Ringer http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services

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