From: Nathan Bossart <nathandbossart@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: David Rowley <dgrowleyml@gmail.com>
Cc: Dmitriy Kuzmin <kuzmin.db4@gmail.com>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Startup process on a hot standby crashes with an error "invalid memory alloc request size 1073741824" while replaying "Standby/LOCK" records
Date: Tue, 4 Oct 2022 17:15:31 -0700
Message-ID: <20221005001531.GC779730@nathanxps13> (raw)
In-Reply-To: <2208668.1664927591@sss.pgh.pa.us>
References: <CAHLDt=_ts0A7Agn=hCpUh+RCFkxd+G6uuT=kcTfqFtGur0dp=A@mail.gmail.com>
<CAApHDvrDg2rJ-sqa7c=wPoHeEGrox46sQ=CFj=FkXqBx26dr0A@mail.gmail.com>
<2138765.1664924048@sss.pgh.pa.us>
<2208668.1664927591@sss.pgh.pa.us>
On Tue, Oct 04, 2022 at 07:53:11PM -0400, Tom Lane wrote:
> I wrote:
>> PFA a quick-hack fix that solves this issue by making per-transaction
>> subsidiary hash tables. That's overkill perhaps; I'm a little worried
>> about whether this slows down normal cases more than it's worth.
>> But we ought to do something about this, because aside from the
>> duplication aspect the current storage of these lists seems mighty
>> space-inefficient.
>
> After further thought, maybe it'd be better to do it as attached,
> with one long-lived hash table for all the locks. This is a shade
> less space-efficient than the current code once you account for
> dynahash overhead, but the per-transaction overhead should be lower
> than the previous patch since we only need to create/destroy a hash
> table entry not a whole hash table.
This feels like a natural way to solve this problem. I saw several cases
of the issue that was fixed with 6301c3a, so I'm inclined to believe this
usage pattern is actually somewhat common.
--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-bugs@postgresql.org
Cc: nathandbossart@gmail.com, tgl@sss.pgh.pa.us, dgrowleyml@gmail.com, kuzmin.db4@gmail.com, pgsql-hackers@lists.postgresql.org
Subject: Re: Startup process on a hot standby crashes with an error "invalid memory alloc request size 1073741824" while replaying "Standby/LOCK" records
In-Reply-To: <20221005001531.GC779730@nathanxps13>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox