3c96f5c647
When updating or deleting a system catalog tuple, it's necessary to acquire RowExclusiveLock on the catalog before looking up the tuple; otherwise a concurrent VACUUM FULL on the catalog might move the tuple to a different TID before we can apply the update. Coding patterns that find the tuple via a table scan aren't at risk here, but when obtaining the tuple from a catalog cache, correct ordering is important; and several routines in foreigncmds.c got it wrong. Noted while running the regression tests in parallel with VACUUM FULL of assorted system catalogs. For consistency I moved all the heap_open calls to the starts of their functions, including a couple for which there was no actual bug. Back-patch to 8.4 where foreigncmds.c was added.
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/.