Re: Full page images in WAL & Cache Invalidation - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Full page images in WAL & Cache Invalidation
Date
Msg-id 2668.1185128738@sss.pgh.pa.us
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In response to Re: Full page images in WAL & Cache Invalidation  ("Florian G. Pflug" <fgp@phlo.org>)
Responses Re: Full page images in WAL & Cache Invalidation  ("Florian G. Pflug" <fgp@phlo.org>)
List pgsql-hackers
"Florian G. Pflug" <fgp@phlo.org> writes:
> Leaving aside the btree issues, are you worried about performance
> problems, or can aggressive cache flushing hurt correctness?

It shouldn't hurt correctness, but I don't think you entirely grasp
the magnitude of the performance hit you'll take.  The last time I
tried running the regression tests with CLOBBER_CACHE_ALWAYS enabled,
they took about one hundred times longer than normal.  Now you are
evidently hoping not to disable the caches entirely, but I don't
understand how you are going to handle the various random
CacheInvalidateRelcache calls that are here and there in the system
(not only in btree).
        regards, tom lane


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