943e881733
On platforms where we can read or write the whole LSN atomically, we do not need to lock the buffer header to prevent torn LSNs. We can do this only on platforms with PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY, and when the pd_lsn field is properly aligned. For historical reasons the PageXLogRecPtr was defined as a struct with two uint32 fields. This replaces it with a single uint64 value, to make the intent clearer. To prevent issues with weak typedefs the value is still wrapped in a struct. This also adjusts heapfuncs() in pageinspect, to ensure proper alignment when reading the LSN from a page on alignment-sensitive hardware. Idea by Andres Freund. Initial patch by Andreas Karlsson, improved by Peter Geoghegan. Minor tweaks by me. Author: Andreas Karlsson <andreas@proxel.se> Author: Peter Geoghegan <pg@bowt.ie> Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: Tomas Vondra <tomas@vondra.me> Discussion: https://postgr.es/m/b6610c3b-3f59-465a-bdbb-8e9259f0abc4@proxel.se
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/.