Not having this check would produce a core dump at startup when running pgstat_read_statsfile(), in the case where the information of a stats kind for an entry in the dshash could not be found. The same check already happens for fixed-numbered stats and entries that are stored with their names. This issue can be seen with custom stats kinds. Note that this problem can be reproduced what what is in the core code: - Tweak the test module injection_points to not load the fixed-numbered stats part, leaving only the variable-numbered stats. - Create an instance with injection_points defined in shared_preload_libraries. - Create a pgstats entry by attaching and running a point. - Restart the server without shared_preload_libraries. The startup process detects that something is wrong and reports a WARNING. Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com> Discussion: https://postgr.es/m/aAieZAvM+K1d89R2@ip-10-97-1-34.eu-west-3.compute.internal
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/.