pg.ddx.io pgsql-hackers@postgresql.org mailing list archive help / color / mirror / Atom feed From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Amit Langote <amitlangote09@gmail.com>
Cc: Andres Freund <andres@anarazel.de>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Cc: amul sul <sulamul@gmail.com>
Subject: Re: hyrax vs. RelationBuildPartitionDesc
Date: Tue, 11 Jun 2019 13:57:16 -0400
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Robert Haas <robertmhaas@gmail.com> writes:
> On Thu, Jun 6, 2019 at 2:48 AM Amit Langote <amitlangote09@gmail.com> wrote:
>> Attached is a patch that applies on top of Robert's pdoldcxt-v1.patch,
>> which seems to fix this issue for me.
> Yeah, that looks right. I think my patch was full of fuzzy thinking
> and inadequate testing; thanks for checking it over and coming up with
> the right solution.
> Anyone else want to look/comment?
I think the existing code is horribly ugly and this is even worse.
It adds cycles to RelationDecrementReferenceCount which is a hotspot
that has no business dealing with this; the invariants are unclear;
and there's no strong reason to think there aren't still cases where
we accumulate lots of copies of old partition descriptors during a
sequence of operations. Basically you're just doubling down on a
wrong design.
As I said upthread, my current inclination is to do nothing in this
area for v12 and then try to replace the whole thing with proper
reference counting in v13. I think the cases where we have a major
leak are corner-case-ish enough that we can leave it as-is for one
release.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, robertmhaas@gmail.com, amitlangote09@gmail.com, andres@anarazel.de, alvherre@2ndquadrant.com, pgsql-hackers@lists.postgresql.org, sulamul@gmail.com
Subject: Re: hyrax vs. RelationBuildPartitionDesc
In-Reply-To: <18286.1560275836@sss.pgh.pa.us>
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