It's not far-fetched that we'd try to read a multixid with an invalid offset in case of bugs or corruption. Or if you call pg_get_multixact_members() after a crash that left behind invalid but unused multixids. Better to get a somewhat descriptive error message if that happens. Discussion: https://www.postgresql.org/message-id/3624730d-6dae-42bf-9458-76c4c965fb27@iki.fi
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/.