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sets for outer joins, in the light of bug #3588 and additional thought and experimentation. The original methodology was fatally flawed for nests of more than two outer joins: it got the relationships between adjacent joins right, but didn't always come to the right conclusions about whether a join could be interchanged with one two or more levels below it. This was largely caused by a mistaken idea that we should use the min_lefthand + min_righthand sets of a sub-join as the minimum left or right input set of an upper join when we conclude that the sub-join can't commute with the upper one. If there's a still-lower join that the sub-join *can* commute with, this method led us to think that that one could commute with the topmost join; which it can't. Another problem (not directly connected to bug #3588) was that make_outerjoininfo's processing-order-dependent method for enforcing outer join identity #3 didn't work right: if we decided that join A could safely commute with lower join B, we dropped all information about sub-joins under B that join A could perhaps not safely commute with, because we removed B's entire min_righthand from A's. To fix, make an explicit computation of all inner join combinations that occur below an outer join, and add to that the full syntactic relsets of any lower outer joins that we determine it can't commute with. This method gives much more direct enforcement of the outer join rearrangement identities, and it turns out not to cost a lot of additional bookkeeping. Thanks to Richard Harris for the bug report and test case.
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 including some of the more common listed below: C++ - http://thaiopensource.org/development/libpqxx/ JDBC - http://jdbc.postgresql.org ODBC - http://odbc.postgresql.org Perl - http://search.cpan.org/~dbdpg/ PHP - http://www.php.net Python - http://www.initd.org/ Ruby - http://ruby.scripting.ca/postgres/ Other language binding are available from a variety of contributing parties. PostgreSQL also has a great number of procedural languages available, a short but not complete list is below: PL/pgSQL - included in PostgreSQL source distribution PL/Perl - included in PostgreSQL source distribution PL/PHP - http://projects.commandprompt.com/projects/public/plphp PL/Python - included in PostgreSQL source distribution PL/Java - http://gborg.postgresql.org/project/pljava/projdisplay.php PL/Tcl - included in PostgreSQL source distribution 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/.