8e18d04d4d
Although user-defined relations can't be directly created in pg_catalog, it's possible for them to end up there, because you can create them in some other schema and then use ALTER TABLE .. SET SCHEMA to move them there. Previously, such relations couldn't afterwards be manipulated, because IsSystemRelation()/IsSystemClass() rejected all attempts to modify objects in the pg_catalog schema, regardless of their origin. With this patch, they now reject only those objects in pg_catalog which were created at initdb-time, allowing most operations on user-created tables in pg_catalog to proceed normally. This patch also adds new functions IsCatalogRelation() and IsCatalogClass(), which is similar to IsSystemRelation() and IsSystemClass() but with a slightly narrower definition: only TOAST tables of system catalogs are included, rather than *all* TOAST tables. This is currently used only for making decisions about when invalidation messages need to be sent, but upcoming logical decoding patches will find other uses for this information. Andres Freund, with some modifications by me.
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. PostgreSQL has many language interfaces, many of which are listed here: http://www.postgresql.org/download See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Changes between all PostgreSQL releases are recorded in the file HISTORY. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at http://www.postgresql.org/download/. For more information look at our web site located at http://www.postgresql.org/.