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71b9549d05
Commit 62c7bd31c8878dd45c9b9b2429ab7a12103f3590 had assorted problems, most visibly that it broke PREPARE TRANSACTION in the presence of session-level advisory locks (which should be ignored by PREPARE), as per a recent complaint from Stephen Rees. More abstractly, the patch made the LockMethodData.transactional flag not merely useless but outright dangerous, because in point of fact that flag no longer tells you anything at all about whether a lock is held transactionally. This fix therefore removes that flag altogether. We now rely entirely on the convention already in use in lock.c that transactional lock holds must be owned by some ResourceOwner, while session holds are never so owned. Setting the locallock struct's owner link to NULL thus denotes a session hold, and there is no redundant marker for that. PREPARE TRANSACTION now works again when there are session-level advisory locks, and it is also able to transfer transactional advisory locks to the prepared transaction, but for implementation reasons it throws an error if we hold both types of lock on a single lockable object. Perhaps it will be worth improving that someday. Assorted other minor cleanup and documentation editing, as well. Back-patch to 9.1, except that in the 9.1 branch I did not remove the LockMethodData.transactional flag for fear of causing an ABI break for any external code that might be examining those structs.
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/.