e656657f2b
Commit 210622c6 accidentally zeroed out pages even if they were found in the buffer pool. It should always lock the page, but it should only zero pages that were not already valid. Otherwise, concurrent readers that hold only a pin could see corrupted page contents changing under their feet. While here, rename ZeroAndLockBuffer() to match the RBM_ flag name. Also restore a some useful comments lost by 210622c6's refactoring, and add some new ones to clarify why we need to use the BM_IO_IN_PROGRESS infrastructure despite not doing I/O. Reported-by: Noah Misch <noah@leadboat.com> Reported-by: Alexander Lakhin <exclusion@gmail.com> Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org> (earlier version) Reviewed-by: Robert Haas <robertmhaas@gmail.com> (earlier version) Discussion: https://postgr.es/m/20240512171658.7e.nmisch@google.com Discussion: https://postgr.es/m/7ed10231-ce47-03d5-d3f9-4aea0dc7d5a4%40gmail.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.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.