Horton

Re: Fix uninitialized xl_running_xacts padding

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2026-02-13T09:50:08Z
Lists: pgsql-hackers 
On Fri, Feb 13, 2026 at 10:39:14AM +0100, Anthonin Bonnefoy wrote:
> The 3 bytes of padding after subxid_overflow were left uninitialized,
> leading to the random 'ca ce 9b' data being written in the WAL. The
> attached patch fixes the issue by zeroing the xl_running_xacts
> structure in LogCurrentRunningXacts using MemSet.

This uninitialized padding exists for as long as this code exists,
down to efc16ea52067.  No objection here to clean up that on HEAD.
--
Michael

Commits

  1. Add test for single-page VACUUM of hash index on INSERT