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Since pg_backup_start() and pg_backup_stop() exist, the tablespace map data and the backup state data (backup_label string until 7d70809) have been allocated in the TopMemoryContext. This approach would cause memory leaks in the session calling these functions if failures happen before pg_backup_stop() ends, leaking more memory on repeated failures. Both things need little memory so that would not be really noticeable for most users, except perhaps connection poolers with long-lived connections able to trigger backup failures with these functions. This commit improves the logic in this area by not allocating anymore the backup-related data that needs to travel across the SQL-callable backup functions in TopMemoryContext, by using instead a dedicated memory context child of TopMemoryContext. The memory context is created in pg_backup_start() and deleted when finishing pg_backup_stop(). In the event of an in-flight failure, this memory context gets reset in the follow-up pg_backup_start() call, so as we are sure that only one run worth of data is leaked at any time. Some cleanup was already done for the backup data on a follow-up call of pg_backup_start(), but using a memory context makes the whole simpler. BASE_BACKUP commands are executed in isolation, relying on the memory context created for replication commands, hence these do not need such an extra logic. Author: Bharath Rupireddy Reviewed-by: Robert Haas, Alvaro Herrera, Cary Huang, Michael Paquier Discussion: https://postgr.es/m/CALj2ACXqvfKF2B0beQ=aJMdWnpNohmBPsRg=EDQj_6y1t2O8mQ@mail.gmail.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. 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/.