From: Noah Misch <noah@leadboat.com>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Handle interleavings between CREATE DATABASE steps and base back
Date: Thu, 01 Feb 2024 21:46:30 +0000
Message-ID: <E1rVetC-004DfU-KD@gemulon.postgresql.org> (raw)
Handle interleavings between CREATE DATABASE steps and base backup.
Restoring a base backup taken in the middle of CreateDirAndVersionFile()
or write_relmap_file() would lose the function's effects. The symptom
was absence of the database directory, PG_VERSION file, or
pg_filenode.map. If missing the directory, recovery would fail. Either
missing file would not fail recovery but would render the new database
unusable. Fix CreateDirAndVersionFile() with the transam/README "action
first and then write a WAL entry" strategy. That has a side benefit of
moving filesystem mutations out of a critical section, reducing the ways
to PANIC. Fix the write_relmap_file() call with a lock acquisition, so
it interacts with checkpoints like non-CREATE DATABASE calls do.
Back-patch to v15, where commit 9c08aea6a3090a396be334cc58c511edab05776a
introduced STRATEGY=WAL_LOG and made it the default.
Discussion: https://postgr.es/m/20240130195003.0a.nmisch@google.com
Branch
------
REL_16_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/6d423e9ff95ac2e62655faa97633155d08dfdd64
Modified Files
--------------
src/backend/commands/dbcommands.c | 44 +++++++++++++++----------------------
src/backend/utils/cache/relmapper.c | 16 ++++++++++++--
2 files changed, 32 insertions(+), 28 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: noah@leadboat.com, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Handle interleavings between CREATE DATABASE steps and base back
In-Reply-To: <E1rVetC-004DfU-KD@gemulon.postgresql.org>
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