We already do this in CreateParallelContext, InitializeParallelDSM, and LaunchParallelWorkers. I suspect the reason why the matching logic was omitted from ReinitializeParallelDSM is that I failed to realize that any memory allocation was happening here -- but shm_mq_attach does allocate, which could result in a shm_mq_handle being allocated in a shorter-lived context than the ParallelContext which points to it. That could result in a crash if the shorter-lived context is freed before the parallel context is destroyed. As far as I am currently aware, there is no way to reach a crash using only code that is present in core PostgreSQL, but extensions could potentially trip over this. Fixing this in the back-branches appears low-risk, so back-patch to all supported versions. Author: Jakub Wartak <jakub.wartak@enterprisedb.com> Co-authored-by: Jeevan Chalke <jeevan.chalke@enterprisedb.com> Backpatch-through: 14 Discussion: http://postgr.es/m/CAKZiRmwfVripa3FGo06=5D1EddpsLu9JY2iJOTgbsxUQ339ogQ@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.
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