d493bed28f
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
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.