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Multiranges are basically sorted arrays of non-overlapping ranges with set-theoretic operations defined over them. Since v14, each range type automatically gets a corresponding multirange datatype. There are both manual and automatic mechanisms for naming multirange types. Once can specify multirange type name using multirange_type_name attribute in CREATE TYPE. Otherwise, a multirange type name is generated automatically. If the range type name contains "range" then we change that to "multirange". Otherwise, we add "_multirange" to the end. Implementation of multiranges comes with a space-efficient internal representation format, which evades extra paddings and duplicated storage of oids. Altogether this format allows fetching a particular range by its index in O(n). Statistic gathering and selectivity estimation are implemented for multiranges. For this purpose, stored multirange is approximated as union range without gaps. This field will likely need improvements in the future. Catversion is bumped. Discussion: https://postgr.es/m/CALNJ-vSUpQ_Y%3DjXvTxt1VYFztaBSsWVXeF1y6gTYQ4bOiWDLgQ%40mail.gmail.com Discussion: https://postgr.es/m/a0b8026459d1e6167933be2104a6174e7d40d0ab.camel%40j-davis.com#fe7218c83b08068bfffb0c5293eceda0 Author: Paul Jungwirth, revised by me Reviewed-by: David Fetter, Corey Huinker, Jeff Davis, Pavel Stehule Reviewed-by: Alvaro Herrera, Tom Lane, Isaac Morland, David G. Johnston Reviewed-by: Zhihong Yu, Alexander Korotkov |
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README
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/.