952365cded
In get_database_list() and get_subscription_list(), the GetTransactionSnapshot() call is not required because the catalog table scans use the catalog snapshot, which is held until the end of the scan. See table_beginscan_catalog(), which calls RegisterSnapshot(GetCatalogSnapshot(relid)). In InitPostgres, it's a little less obvious that it's not required, but still true I believe. All the catalog lookups in InitPostgres() also use the catalog snapshot, and the looked up values are copied while still holding the snapshot. Furthermore, as the removed FIXME comments said, calling GetTransactionSnapshot() didn't really prevent MyProc->xmin from being reset anyway. Discussion: https://www.postgresql.org/message-id/7c56f180-b9e1-481e-8c1d-efa63de3ecbb@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/.