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Previously we held buffer locks for two buffer mapping partitions at the same time to change the identity of buffers. Particularly for extending relations needing to hold the extension lock while acquiring a victim buffer is painful.But it also creates a bottleneck for workloads that just involve reads. Now we instead first acquire a victim buffer and write it out, if necessary. Then we remove that buffer from the old partition with just the old partition's partition lock held and insert it into the new partition with just that partition's lock held. By separating out the victim buffer acquisition, future commits will be able to change relation extensions to scale better. On my workstation, a micro-benchmark exercising buffered reads strenuously and under a lot of concurrency, sees a >2x improvement. Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi> Reviewed-by: Melanie Plageman <melanieplageman@gmail.com> Discussion: https://postgr.es/m/20221029025420.eplyow6k7tgu6he3@awork3.anarazel.de
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/.