4331d20f4d
If no DSM segment can be created, a ParallelContext can still be
created with zero workers, but its seg pointer is NULL. Parallel
autovacuum registered a segment detach callback on that NULL pointer,
crashing the autovacuum worker.
Fix by setting up the shared cost parameters and the detach callback
only when the parallel context has workers, as there are no workers to
propagate the parameters to otherwise.
Oversight in commit 1ff3180ca0.
Found by Bharath using AI assisted review with Claude.
Reported-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Author: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Discussion: https://postgr.es/m/CALj2ACVjBN03Fq4XWgKH1zOfkapK6-P3ufNLHUHnZcW1zPm+Mg@mail.gmail.com
Backpatch-through: 19
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/19/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/19/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/.