Re: Are cached IMMUTABLE values persistent between sessions

From: Alvaro Herrera <alvherre(at)surnet(dot)cl>
To: Donald Fraser <postgres(at)kiwi-fraser(dot)net>
Cc: "[ADMIN]" <pgsql-admin(at)postgresql(dot)org>
Subject: Re: Are cached IMMUTABLE values persistent between sessions
Date: 2005-06-23 14:40:55
Message-ID: 20050623144055.GC7656@surnet.cl
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On Thu, Jun 23, 2005 at 02:26:23PM +0100, Donald Fraser wrote:
> Is the returned value of a function defined as IMMUTABLE cached
> globally? In other words could postgresql potentially return a cached
> value obtained from one client session to a different client session?

Return values from functions are never cached at all, not even for
immutable functions. The mutability flag (currently) is only used for
deciding the "optimizability" of the function within the query's
execution.

--
Alvaro Herrera (<alvherre[a]surnet.cl>)
"El que vive para el futuro es un iluso, y el que vive para el pasado,
un imbécil" (Luis Adler, "Los tripulantes de la noche")

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