2c78940527
This set of changes removes the list of available buffers and instead simply uses the clock-sweep algorithm to find and return an available buffer. This also removes the have_free_buffer() function and simply caps the pg_autoprewarm process to at most NBuffers. While on the surface this appears to be removing an optimization it is in fact eliminating code that induces overhead in the form of synchronization that is problematic for multi-core systems. The main reason for removing the freelist, however, is not the moderate improvement in scalability, but that having the freelist would require dedicated complexity in several upcoming patches. As we have not been able to find a case benefiting from the freelist... Author: Greg Burd <greg@burd.me> Reviewed-by: Tomas Vondra <tomas@vondra.me> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/70C6A5B5-2A20-4D0B-BC73-EB09DD62D61C@getmailspring.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/.