<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >GiST Indexes</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 8.0.11 Documentation" HREF="index.html"><LINK REL="UP" TITLE="Internals" HREF="internals.html"><LINK REL="PREVIOUS" TITLE="Index Cost Estimation Functions" HREF="indexcost.html"><LINK REL="NEXT" TITLE="Extensibility" HREF="extensibility.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"><META NAME="creation" CONTENT="2007-02-02T03:57:22"></HEAD ><BODY CLASS="CHAPTER" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="5" ALIGN="center" VALIGN="bottom" >PostgreSQL 8.0.11 Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="indexcost.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="indexcost.html" >Fast Backward</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="storage.html" >Fast Forward</A ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="extensibility.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="CHAPTER" ><H1 ><A NAME="GIST" ></A >Chapter 48. GiST Indexes</H1 ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT >48.1. <A HREF="gist.html#INTRO" >Introduction</A ></DT ><DT >48.2. <A HREF="extensibility.html" >Extensibility</A ></DT ><DT >48.3. <A HREF="implementation.html" >Implementation</A ></DT ><DT >48.4. <A HREF="limitations.html" >Limitations</A ></DT ><DT >48.5. <A HREF="examples.html" >Examples</A ></DT ></DL ></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="INTRO" >48.1. Introduction</A ></H1 ><P > <A NAME="AEN57961" ></A > <A NAME="AEN57964" ></A > <ACRONYM CLASS="ACRONYM" >GiST</ACRONYM > stands for Generalized Search Tree. It is a balanced, tree-structured access method, that acts as a base template in which to implement arbitrary indexing schemes. B+-trees, R-trees and many other indexing schemes can be implemented in <ACRONYM CLASS="ACRONYM" >GiST</ACRONYM >. </P ><P > One advantage of <ACRONYM CLASS="ACRONYM" >GiST</ACRONYM > is that it allows the development of custom data types with the appropriate access methods, by an expert in the domain of the data type, rather than a database expert. </P ><P > Some of the information here is derived from <A HREF="http://gist.cs.berkeley.edu/" TARGET="_top" >the University of California at Berkeley's GiST Indexing Project web site</A > and Marcel Kornacker's thesis, <A HREF="http://citeseer.nj.nec.com/448594.html" TARGET="_top" >Access Methods for Next-Generation Database Systems</A >. The <ACRONYM CLASS="ACRONYM" >GiST</ACRONYM > implementation in <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > is primarily maintained by Teodor Sigaev and Oleg Bartunov, and there is more information on their website: <A HREF="http://www.sai.msu.su/~megera/postgres/gist/" TARGET="_top" >http://www.sai.msu.su/~megera/postgres/gist/</A >. </P ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="indexcost.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="extensibility.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Index Cost Estimation Functions</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="internals.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Extensibility</TD ></TR ></TABLE ></DIV ></BODY ></HTML >