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for scanning one term of an OR clause if the index's predicate is implied by that same OR clause term (possibly in conjunction with top-level WHERE clauses). Per recent example from Dawid Kuroczko, http://archives.postgresql.org/pgsql-performance/2004-10/msg00095.php Also, fix a very long-standing bug in index predicate testing, namely the bizarre ordering of decomposition of predicate and restriction clauses. AFAICS the correct way is to break down the predicate all the way, and then for each component term see if you can prove it from the entire restriction set. The original coding had a purely-implementation-artifact distinction between ANDing at the top level and ANDing below that, and proceeded to get the decomposition order wrong everywhere below the top level, with the result that even slightly complicated AND/OR predicates could not be proven. For instance, given create index foop on foo(f2) where f1=42 or f1=1 or (f1 = 11 and f2 = 55); the old code would fail to match this index to the query select * from foo where f1 = 11 and f2 = 55; when it obviously ought to match.
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. The JDBC, ODBC, C++, Python, and Tcl interfaces have been moved to the PostgreSQL Projects Web Site at http://gborg.postgresql.org for separate maintenance. A Perl DBI/DBD driver is available from CPAN. 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 ftp://ftp.postgresql.org/pub/. For more information look at our web site located at http://www.postgresql.org/.