
Similarly to B-tree, GiST index access method gets support of INCLUDE attributes. These attributes aren't used for tree navigation and aren't present in non-leaf pages. But they are present in leaf pages and can be fetched during index-only scan. The point of having INCLUDE attributes in GiST indexes is slightly different from the point of having them in B-tree. The main point of INCLUDE attributes in B-tree is to define UNIQUE constraint over part of attributes enabled for index-only scan. In GiST the main point of INCLUDE attributes is to use index-only scan for attributes, whose data types don't have GiST opclasses. Discussion: https://postgr.es/m/73A1A452-AD5F-40D4-BD61-978622FF75C1%40yandex-team.ru Author: Andrey Borodin, with small changes by me Reviewed-by: Andreas Karlsson
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, many of which are listed here: https://www.postgresql.org/download 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. 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 https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.
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