40e2e5e92b
A number of pg_upgrade steps require connecting to every database in the cluster and running the same query in each one. When there are many databases, these steps are particularly time-consuming, especially since they are performed sequentially, i.e., we connect to a database, run the query, and process the results before moving on to the next database. This commit introduces a new framework that makes it easy to parallelize most of these once-in-each-database tasks by processing multiple databases concurrently. This framework manages a set of slots that follow a simple state machine, and it uses libpq's asynchronous APIs to establish the connections and run the queries. The --jobs option is used to determine the number of slots to use. To use this new task framework, callers simply need to provide the query and a callback function to process its results, and the framework takes care of the rest. A more complete description is provided at the top of the new task.c file. None of the eligible once-in-each-database tasks are converted to use this new framework in this commit. That will be done via several follow-up commits. Reviewed-by: Jeff Davis, Robert Haas, Daniel Gustafsson, Ilya Gladyshev, Corey Huinker Discussion: https://postgr.es/m/20240516211638.GA1688936%40nathanxps13
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/.