Horton

Re: BUG #17254: Crash with 0xC0000409 in pg_stat_statements when pg_stat_tmp\pgss_query_texts.stat exceeded 2GB.

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Juan José Santamaría Flecha <juanjo.santamaria@gmail.com>
Cc: egashira.yusuke@fujitsu.com, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Date: 2021-10-31T17:07:42Z
Lists: pgsql-bugs

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I wrote:
> =?UTF-8?Q?Juan_Jos=C3=A9_Santamar=C3=ADa_Flecha?= <juanjo.santamaria@gmail.com> writes:
>> On Sat, Oct 30, 2021 at 6:26 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> I think instead, we need to turn the subsequent one-off read() call into a
>>> loop that reads no more than INT_MAX bytes at a time.  It'd be possible
>>> to restrict that to Windows, but probably no harm in doing it the same
>>> way everywhere.

>> Seems reasonable to me, can such a change be back-patched?

> Don't see why not.

Here's a quick patch for that.  I don't have any ability to check it
on Windows, but the logic is easy to verify by reducing the arbitrary
constant to something small.  (I used 1GB, not INT_MAX, because I figured
we ought to read in multiples of a filesystem block if possible.)

			regards, tom lane

Commits

  1. Don't try to read a multi-GB pg_stat_statements file in one call.