Re: shared_preload_libraries support on Win32?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Andrew Dunstan <andrew(at)dunslane(dot)net>
Cc: korryd(at)enterprisedb(dot)com, pgsql-hackers(at)postgresql(dot)org
Subject: Re: shared_preload_libraries support on Win32?
Date: 2007-01-29 16:53:51
Message-ID: 11414.1170089631@sss.pgh.pa.us
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Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
> Tom Lane wrote:
>> I don't entirely see the point. The value of shared_preload_libraries
>> is to avoid paying per-process overhead to load the libraries, and that
>> benefit is already lost in a fork/exec world. Might as well just let
>> the libraries be loaded when and if needed.

> The only benefit I can see is that it would assist in having a common
> configuration.

Actually ... I take that back. I was thinking of the original purpose
of preload_libraries, which was strictly performance optimization.
But in the new world of plugins there may be functional reasons for
wanting libraries to be loaded into backends --- and
shared_preload_libraries is not isomorphic to local_preload_libraries.
The permissions situation is different.

Korry's right, we should force re-loading of shared_preload_libraries
in the EXEC_BACKEND case. The needed documentation change is to point
out that on Windows this is not a performance win, but it might still
be wanted for instrumentation or debugging plugins.

regards, tom lane

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