<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!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>Chapter 11. Indexes</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="typeconv-select.html" title="10.6. SELECT Output Columns" /><link rel="next" href="indexes-intro.html" title="11.1. Introduction" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">Chapter 11. Indexes</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="typeconv-select.html" title="10.6. SELECT Output Columns">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql.html" title="Part II. The SQL Language">Up</a></td><th width="60%" align="center">Part II. The SQL Language</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="indexes-intro.html" title="11.1. Introduction">Next</a></td></tr></table><hr></hr></div><div class="chapter" id="INDEXES"><div class="titlepage"><div><div><h2 class="title">Chapter 11. Indexes</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="sect1"><a href="indexes-intro.html">11.1. Introduction</a></span></dt><dt><span class="sect1"><a href="indexes-types.html">11.2. Index Types</a></span></dt><dt><span class="sect1"><a href="indexes-multicolumn.html">11.3. Multicolumn Indexes</a></span></dt><dt><span class="sect1"><a href="indexes-ordering.html">11.4. Indexes and <code class="literal">ORDER BY</code></a></span></dt><dt><span class="sect1"><a href="indexes-bitmap-scans.html">11.5. Combining Multiple Indexes</a></span></dt><dt><span class="sect1"><a href="indexes-unique.html">11.6. Unique Indexes</a></span></dt><dt><span class="sect1"><a href="indexes-expressional.html">11.7. Indexes on Expressions</a></span></dt><dt><span class="sect1"><a href="indexes-partial.html">11.8. Partial Indexes</a></span></dt><dt><span class="sect1"><a href="indexes-index-only-scans.html">11.9. Index-Only Scans and Covering Indexes</a></span></dt><dt><span class="sect1"><a href="indexes-opclass.html">11.10. Operator Classes and Operator Families</a></span></dt><dt><span class="sect1"><a href="indexes-collations.html">11.11. Indexes and Collations</a></span></dt><dt><span class="sect1"><a href="indexes-examine.html">11.12. Examining Index Usage</a></span></dt></dl></div><a id="id-1.5.10.2" class="indexterm"></a><p> Indexes are a common way to enhance database performance. An index allows the database server to find and retrieve specific rows much faster than it could do without an index. But indexes also add overhead to the database system as a whole, so they should be used sensibly. </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="typeconv-select.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="indexes-intro.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">10.6. <code class="literal">SELECT</code> Output Columns </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 11.1. Introduction</td></tr></table></div></body></html>
