Re: Bypassing shared_buffers - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Bypassing shared_buffers
Date
Msg-id 2034773.1686792150@sss.pgh.pa.us
Whole thread Raw
In response to Bypassing shared_buffers  (Vladimir Churyukin <vladimir@churyukin.com>)
Responses Re: Bypassing shared_buffers
List pgsql-hackers
Vladimir Churyukin <vladimir@churyukin.com> writes:
> There is often a need to test particular queries executed in the worst-case
> scenario, i.e. right after a server restart or with no or minimal amount of
> data in shared buffers. In Postgres it's currently hard to achieve (other
> than to restart the server completely to run a single query, which is not
> practical). Is there a simple way to introduce a GUC variable that makes
> queries bypass shared_buffers and always read from storage? It would make
> testing like that orders of magnitude simpler. I mean, are there serious
> technical obstacles or any other objections to that idea in principle?

It's a complete non-starter.  Pages on disk are not necessarily up to
date; but what is in shared buffers is.

            regards, tom lane



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