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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: hyrax vs. RelationBuildPartitionDesc
Date: Thu, 14 Mar 2019 12:36:20 -0400
Message-ID: <3969.1552581380@sss.pgh.pa.us> (raw)
In-Reply-To: <CA+TgmoY71GwY8WhQKBH+7yexyZEw6WDbFBtj2E3EDszc0LnSqQ@mail.gmail.com>
References: <CA+TgmoY3bRmGB6-DUnoVy5fJoreiBJ43rwMrQRCdPXuKt4Ykaw@mail.gmail.com>
	<20190313164232.GA5270@alvherre.pgsql>
	<CA+Tgmoabw8KW9rx6ThnUTR_ofJC8GwVaC+XMe7HkZvsG7J1rvA@mail.gmail.com>
	<7448.1552497345@sss.pgh.pa.us>
	<7961.1552498252@sss.pgh.pa.us>
	<CA+TgmoaZ021fRZawzU_gozwgHMo-tXJc12uf3MJoA6k=HZsLJA@mail.gmail.com>
	<10788.1552501588@sss.pgh.pa.us>
	<CA+TgmoYd3vqd26RiT4sp7Mez3oQf-AxAzdBpEeTyCNF-7OchhA@mail.gmail.com>
	<CA+TgmoY71GwY8WhQKBH+7yexyZEw6WDbFBtj2E3EDszc0LnSqQ@mail.gmail.com>

Robert Haas <robertmhaas@gmail.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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