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< * Use bitmaps to combine existing indexes [performance] > * Allow the creation of bitmap indexes which can be quickly combined > with other bitmap indexes 255,257c256,266 < Bitmap indexes allow single indexed columns to be combined to < dynamically create a composite index to match a specific query. Each < index is a bitmap, and the bitmaps are AND'ed or OR'ed to be combined. > Bitmap indexes index single columns that can be combined with other bitmap > indexes to dynamically create a composite index to match a specific query. > Each index is a bitmap, and the bitmaps are bitwise AND'ed or OR'ed to be > combined. Such indexes could be more compact if there are few unique > value. Also, perhaps they can be lossy requiring a scan of the heap page > to find matching rows. > > * Allow non-bitmap indexes to be combined > > Do lookups on non-bitmap indexes and create bitmaps in memory that can be > combined with other indexes. |
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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/.