The originally submitted code (using bit masking) was correct when the number of slots was restricted to be a power of two -- but that limitation was removed during development that led to commit 53c2a97a9266, which made the bank selection code incorrect. This led to always using a smaller number of banks than available. Change said code to use integer modulo instead, which works correctly with an arbitrary number of banks. It's likely that we could improve on this to avoid runtime use of integer division. But with this change we're, at least, not wasting memory on unused banks, and more banks mean less contention, which is likely to have a much higher performance impact than a single instruction's latency. Author: Yura Sokolov <y.sokolov@postgrespro.ru> Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru> Discussion: https://postgr.es/m/9444dc46-ca47-43ed-9058-89c456316306@postgrespro.ru
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/.