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that it's good to join where there are join clauses rather than where there are not. Also enable it to generate bushy plans at need, so that it doesn't fail in the presence of multiple IN clauses containing sub-joins. These changes appear to improve the behavior enough that we can substantially reduce the default pool size and generations count, thereby decreasing the runtime, and yet get as good or better plans as we were getting in 7.4. Consequently, adjust the default GEQO parameters. I also modified the way geqo_effort is used so that it affects both population size and number of generations; it's now useful as a single control to adjust the GEQO runtime-vs-plan-quality tradeoff. Bump geqo_threshold to 12, since even with these changes GEQO seems to be slower than the regular planner at 11 relations.
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 several language bindings, including C and Tcl. The JDBC, ODBC, C++, and Python 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/.