Re: hyrax vs. RelationBuildPartitionDesc

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: hyrax vs. RelationBuildPartitionDesc
Date: 2019-03-14 16:36:20
Message-ID: 3969.1552581380@sss.pgh.pa.us
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Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> I did not back-patch, because the code is in a different file in v11,
> none of the hunks of the patch apply on v11, and v11 is not failing on
> hyrax.

Hmm, I wonder why not. I suppose the answer is that
the leak is worse in HEAD than before, but how come?

I followed your reference to 898e5e329, and I've got to say that
the hunk it adds in relcache.c looks fishy as can be. The argument
that the rd_pdcxt "will get cleaned up eventually" reads to me like
"this leaks memory like a sieve", especially in the repeated-rebuild
scenario which is exactly what CLOBBER_CACHE_ALWAYS would provoke.
Probably the only thing that keeps it from being effectively a
session-lifespan leak is that CCA will generally result in relcache
entries being flushed entirely as soon as their refcount goes to 0.
Still, because of that, I wouldn't think it'd move the needle very
much on a CCA animal; so my guess is that there's something else.

regards, tom lane

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