From: Tom Lane <tgl@sss.pgh.pa.us>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Fix file descriptor leakages in pg_waldump.
Date: Wed, 25 Mar 2026 22:37:40 +0000
Message-ID: <E1w5Wr5-001Rpa-2a@gemulon.postgresql.org> (raw)
Fix file descriptor leakages in pg_waldump.
TarWALDumpCloseSegment was of the opinion that it didn't need to
do anything. It was mistaken: it has to close the open file if
any, because nothing else will, leading to a descriptor leak.
In addition, we failed to ensure that any file being read by the
XLogReader machinery gets closed before the atexit callback tries to
cleanup the temporary directory holding spilled WAL files. While the
file would have been closed already in case of a success exit, this
doesn't happen in case of pg_fatal() exits. The least messy way
to fix that is to move the atexit function into pg_waldump.c,
where it has easier access to the XLogReaderState pointer and to
WALDumpCloseSegment.
These FD leakages are pretty insignificant on Unix-ish platforms,
but they're a bug on Windows, because they prevent successful cleanup
of the temporary directory for extracted WAL files. (Windows can't
delete a directory that holds a deleted-but-still-open file.)
This is visible in occasional buildfarm failures.
This code's all new as of commit b15c15139, so no need for back-patch.
Discussion: https://postgr.es/m/374225.1774459521@sss.pgh.pa.us
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/03b1e30e7aa5c0d83514db4156cfc80632f50493
Modified Files
--------------
src/bin/pg_waldump/archive_waldump.c | 26 +++------------------
src/bin/pg_waldump/pg_waldump.c | 44 +++++++++++++++++++++++++++++++++---
2 files changed, 44 insertions(+), 26 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: tgl@sss.pgh.pa.us, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Fix file descriptor leakages in pg_waldump.
In-Reply-To: <E1w5Wr5-001Rpa-2a@gemulon.postgresql.org>
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