202b12774d
Previously we would have the following inaccuracies when a backend tried to read in a buffer, but that buffer was read in concurrently by another backend: - the read IO was double-counted in the global buffer access stats (pgBufferUsage) - the buffer hit was not accounted for in: - global buffer access statistics - pg_stat_io - relation level IO stats - vacuum cost balancing While trying to read in a buffer that is concurrently read in by another backend is not a common occurrence, it's also not that rare, e.g. due to concurrent sequential scans on the same relation. This scenario has become more likely in PG 17, due to the introducing of read streams, which can pin multiple buffers before calling StartBufferIO() for all the buffers. This behaviour has historically grown, but there doesn't seem to be any reason to continue with the wrong accounting. Reviewed-by: Melanie Plageman <melanieplageman@gmail.com> Discussion: https://postgr.es/m/CAAKRu_Zk-B08AzPsO-6680LUHLOCGaNJYofaxTFseLa=OepV1g@mail.gmail.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/.