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The previous commit introduced the infrastructure to start io_workers. This commit actually makes the workers execute IOs. IO workers consume IOs from a shared memory submission queue, run traditional synchronous system calls, and perform the shared completion handling immediately. Client code submits most requests by pushing IOs into the submission queue, and waits (if necessary) using condition variables. Some IOs cannot be performed in another process due to lack of infrastructure for reopening the file, and must processed synchronously by the client code when submitted. For now the default io_method is changed to "worker". We should re-evaluate that around beta1, we might want to be careful and set the default to "sync" for 18. Reviewed-by: Noah Misch <noah@leadboat.com> Co-authored-by: Thomas Munro <thomas.munro@gmail.com> Co-authored-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/uvrtrknj4kdytuboidbhwclo4gxhswwcpgadptsjvjqcluzmah%40brqs62irg4dt Discussion: https://postgr.es/m/20210223100344.llw5an2aklengrmn@alap3.anarazel.de Discussion: https://postgr.es/m/stj36ea6yyhoxtqkhpieia2z4krnam7qyetc57rfezgk4zgapf@gcnactj4z56m
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/.