This field is not used directly in the code, but it is important for query jumbling to be able to make a difference between a named DEALLOCATE and DEALLOCATE ALL (see bb45156f342c). This behavior is tracked in the regression tests of pg_stat_statements, but the reason why this field is important can be easily missed, as a recent discussion has proved, so let's improve its comment to document the reason why it needs to be around. Wording has been suggested by Tom Lane Discussion: https://postgr.es/m/Zih1ATt37YFda8_p@paquier.xyz
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/.