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Until now, all extended statistics on a given relation were built in the same memory context, without resetting. Some of the memory was released explicitly, but not all of it - for example memory allocated while detoasting values is hard to free. This is how it worked since extended statistics were introduced in PostgreSQL 10, but adding support for extended stats on expressions made the issue somewhat worse as it increases the number of statistics to build. Fixed by adding a memory context which gets reset after building each statistics object (all the statistics kinds included in it). Resetting it after building each statistics kind would be even better, but it would require more invasive changes and copying of results, making it harder to backpatch. Backpatch to PostgreSQL 10, where extended statistics were introduced. Author: Justin Pryzby Reported-by: Justin Pryzby Reviewed-by: Tomas Vondra Backpatch-through: 10 Discussion: https://www.postgresql.org/message-id/20210915200928.GP831%40telsasoft.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/.