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PostgreSQL. This hash function replaces the one used by hash indexes and the catalog cache. Hash joins use a different, relatively poor-quality hash function, but I'll fix that later. As suggested by Tom Lane, this patch also changes the size of the fixed hash table used by the catalog cache to be a power-of-2 (instead of a prime: I chose 256 instead of 257). This allows the catcache to lookup hash buckets using a simple bitmask. This should improve the performance of the catalog cache slightly, since the previous method (modulo a prime) was slow. In my tests, this improves the performance of hash indexes by between 4% and 8%; the performance when using btree indexes or seqscans is basically unchanged. Neil Conway <neilconway@rogers.com>
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, C++, Perl, Python, and Tcl, as well as drivers for JDBC and ODBC. 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/.