185e304263
This patch reuses the existing aggtransspace in pg_aggregate to signal that an aggregate's transition state can grow unboundedly. If aggtransspace is set to a negative value, it now indicates that the transition state may consume unpredictable or large amounts of memory, such as in aggregates like array_agg or string_agg that accumulate input rows. This information can be used by the planner to avoid applying memory-sensitive optimizations (e.g., eager aggregation) when there is a risk of excessive memory usage during partial aggregation. Bump catalog version. Per idea from Robert Haas, though applied differently than originally suggested. Discussion: https://postgr.es/m/CA+TgmoYbkvYwLa+1vOP7RDY7kO2=A7rppoPusoRXe44VDOGBPg@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.
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/.