8f9622bbb3
Truncating or dropping a table is treated like deletion of all tuples, and check for conflicts accordingly. If a table is clustered or rewritten by ALTER TABLE, all predicate locks on the heap are promoted to relation-level locks, because the tuple or page ids of any existing tuples will change and won't be valid after rewriting the table. Arguably ALTER TABLE should be treated like a mass-UPDATE of every row, but if you e.g change the datatype of a column, you could also argue that it's just a change to the physical layout, not a logical change. Reindexing promotes all locks on the index to relation-level lock on the heap. Kevin Grittner, with a lot of cosmetic changes 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/.