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1<?xml version="1.0" encoding="UTF-8" standalone="no"?>2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>F.9. btree_gist — GiST operator classes with B-tree behavior</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="btree-gin.html" title="F.8. btree_gin — GIN operator classes with B-tree behavior" /><link rel="next" href="citext.html" title="F.10. citext — a case-insensitive character string type" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">F.9. btree_gist — GiST operator classes with B-tree behavior</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="btree-gin.html" title="F.8. btree_gin — GIN operator classes with B-tree behavior">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="contrib.html" title="Appendix F. Additional Supplied Modules and Extensions">Up</a></td><th width="60%" align="center">Appendix F. Additional Supplied Modules and Extensions</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="citext.html" title="F.10. citext — a case-insensitive character string type">Next</a></td></tr></table><hr /></div><div class="sect1" id="BTREE-GIST"><div class="titlepage"><div><div><h2 class="title" style="clear: both">F.9. btree_gist — GiST operator classes with B-tree behavior <a href="#BTREE-GIST" class="id_link">#</a></h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="btree-gist.html#BTREE-GIST-EXAMPLE-USAGE">F.9.1. Example Usage</a></span></dt><dt><span class="sect2"><a href="btree-gist.html#BTREE-GIST-AUTHORS">F.9.2. Authors</a></span></dt></dl></div><a id="id-1.11.7.19.2" class="indexterm"></a><p>3 <code class="filename">btree_gist</code> provides GiST index operator classes that4 implement B-tree equivalent behavior for the data types5 <code class="type">int2</code>, <code class="type">int4</code>, <code class="type">int8</code>, <code class="type">float4</code>,6 <code class="type">float8</code>, <code class="type">numeric</code>, <code class="type">timestamp with time zone</code>,7 <code class="type">timestamp without time zone</code>, <code class="type">time with time zone</code>,8 <code class="type">time without time zone</code>, <code class="type">date</code>, <code class="type">interval</code>,9 <code class="type">oid</code>, <code class="type">money</code>, <code class="type">char</code>,10 <code class="type">varchar</code>, <code class="type">text</code>, <code class="type">bytea</code>, <code class="type">bit</code>,11 <code class="type">varbit</code>, <code class="type">macaddr</code>, <code class="type">macaddr8</code>, <code class="type">inet</code>,12 <code class="type">cidr</code>, <code class="type">uuid</code>, <code class="type">bool</code> and all <code class="type">enum</code> types.13 </p><p>14 In general, these operator classes will not outperform the equivalent15 standard B-tree index methods, and they lack one major feature of the16 standard B-tree code: the ability to enforce uniqueness. However,17 they provide some other features that are not available with a B-tree18 index, as described below. Also, these operator classes are useful19 when a multicolumn GiST index is needed, wherein some of the columns20 are of data types that are only indexable with GiST but other columns21 are just simple data types. Lastly, these operator classes are useful for22 GiST testing and as a base for developing other GiST operator classes.23 </p><p>24 In addition to the typical B-tree search operators, <code class="filename">btree_gist</code>25 also provides index support for <code class="literal"><></code> (<span class="quote">“<span class="quote">not26 equals</span>”</span>). This may be useful in combination with an27 <a class="link" href="sql-createtable.html#SQL-CREATETABLE-EXCLUDE">exclusion constraint</a>,28 as described below.29 </p><p>30 Also, for data types for which there is a natural distance metric,31 <code class="filename">btree_gist</code> defines a distance operator <code class="literal"><-></code>,32 and provides GiST index support for nearest-neighbor searches using33 this operator. Distance operators are provided for34 <code class="type">int2</code>, <code class="type">int4</code>, <code class="type">int8</code>, <code class="type">float4</code>,35 <code class="type">float8</code>, <code class="type">timestamp with time zone</code>,36 <code class="type">timestamp without time zone</code>,37 <code class="type">time without time zone</code>, <code class="type">date</code>, <code class="type">interval</code>,38 <code class="type">oid</code>, and <code class="type">money</code>.39 </p><p>40 This module is considered <span class="quote">“<span class="quote">trusted</span>”</span>, that is, it can be41 installed by non-superusers who have <code class="literal">CREATE</code> privilege42 on the current database.43 </p><div class="sect2" id="BTREE-GIST-EXAMPLE-USAGE"><div class="titlepage"><div><div><h3 class="title">F.9.1. Example Usage <a href="#BTREE-GIST-EXAMPLE-USAGE" class="id_link">#</a></h3></div></div></div><p>44 Simple example using <code class="literal">btree_gist</code> instead of <code class="literal">btree</code>:45 </p><pre class="programlisting">46CREATE TABLE test (a int4);47-- create index48CREATE INDEX testidx ON test USING GIST (a);49-- query50SELECT * FROM test WHERE a < 10;51-- nearest-neighbor search: find the ten entries closest to "42"52SELECT *, a <-> 42 AS dist FROM test ORDER BY a <-> 42 LIMIT 10;53</pre><p>54 Use an <a class="link" href="sql-createtable.html#SQL-CREATETABLE-EXCLUDE">exclusion55 constraint</a> to enforce the rule that a cage at a zoo56 can contain only one kind of animal:57 </p><pre class="programlisting">58=> CREATE TABLE zoo (59 cage INTEGER,60 animal TEXT,61 EXCLUDE USING GIST (cage WITH =, animal WITH <>)62);63 64=> INSERT INTO zoo VALUES(123, 'zebra');65INSERT 0 166=> INSERT INTO zoo VALUES(123, 'zebra');67INSERT 0 168=> INSERT INTO zoo VALUES(123, 'lion');69ERROR: conflicting key value violates exclusion constraint "zoo_cage_animal_excl"70DETAIL: Key (cage, animal)=(123, lion) conflicts with existing key (cage, animal)=(123, zebra).71=> INSERT INTO zoo VALUES(124, 'lion');72INSERT 0 173</pre></div><div class="sect2" id="BTREE-GIST-AUTHORS"><div class="titlepage"><div><div><h3 class="title">F.9.2. Authors <a href="#BTREE-GIST-AUTHORS" class="id_link">#</a></h3></div></div></div><p>74 Teodor Sigaev (<code class="email"><<a class="email" href="mailto:teodor@stack.net">teodor@stack.net</a>></code>),75 Oleg Bartunov (<code class="email"><<a class="email" href="mailto:oleg@sai.msu.su">oleg@sai.msu.su</a>></code>),76 Janko Richter (<code class="email"><<a class="email" href="mailto:jankorichter@yahoo.de">jankorichter@yahoo.de</a>></code>), and77 Paul Jungwirth (<code class="email"><<a class="email" href="mailto:pj@illuminatedcomputing.com">pj@illuminatedcomputing.com</a>></code>). See78 <a class="ulink" href="http://www.sai.msu.su/~megera/postgres/gist/" target="_top">http://www.sai.msu.su/~megera/postgres/gist/</a>79 for additional information.80 </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="btree-gin.html" title="F.8. btree_gin — GIN operator classes with B-tree behavior">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="contrib.html" title="Appendix F. 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