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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-13 13:44:03 +0000 |
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| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-13 13:44:03 +0000 |
| commit | 293913568e6a7a86fd1479e1cff8e2ecb58d6568 (patch) | |
| tree | fc3b469a3ec5ab71b36ea97cc7aaddb838423a0c /doc/src/sgml/html/gin-intro.html | |
| parent | Initial commit. (diff) | |
| download | postgresql-16-293913568e6a7a86fd1479e1cff8e2ecb58d6568.tar.xz postgresql-16-293913568e6a7a86fd1479e1cff8e2ecb58d6568.zip | |
Adding upstream version 16.2.upstream/16.2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/src/sgml/html/gin-intro.html')
| -rw-r--r-- | doc/src/sgml/html/gin-intro.html | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/doc/src/sgml/html/gin-intro.html b/doc/src/sgml/html/gin-intro.html new file mode 100644 index 0000000..2d5165f --- /dev/null +++ b/doc/src/sgml/html/gin-intro.html @@ -0,0 +1,40 @@ +<?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>70.1. Introduction</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="gin.html" title="Chapter 70. GIN Indexes" /><link rel="next" href="gin-builtin-opclasses.html" title="70.2. Built-in Operator Classes" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">70.1. Introduction</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="gin.html" title="Chapter 70. GIN Indexes">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="gin.html" title="Chapter 70. GIN Indexes">Up</a></td><th width="60%" align="center">Chapter 70. GIN Indexes</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="gin-builtin-opclasses.html" title="70.2. Built-in Operator Classes">Next</a></td></tr></table><hr /></div><div class="sect1" id="GIN-INTRO"><div class="titlepage"><div><div><h2 class="title" style="clear: both">70.1. Introduction <a href="#GIN-INTRO" class="id_link">#</a></h2></div></div></div><p> + <acronym class="acronym">GIN</acronym> stands for Generalized Inverted Index. + <acronym class="acronym">GIN</acronym> is designed for handling cases where the items + to be indexed are composite values, and the queries to be handled by + the index need to search for element values that appear within + the composite items. For example, the items could be documents, + and the queries could be searches for documents containing specific words. + </p><p> + We use the word <em class="firstterm">item</em> to refer to a composite value that + is to be indexed, and the word <em class="firstterm">key</em> to refer to an element + value. <acronym class="acronym">GIN</acronym> always stores and searches for keys, + not item values per se. + </p><p> + A <acronym class="acronym">GIN</acronym> index stores a set of (key, posting list) pairs, + where a <em class="firstterm">posting list</em> is a set of row IDs in which the key + occurs. The same row ID can appear in multiple posting lists, since + an item can contain more than one key. Each key value is stored only + once, so a <acronym class="acronym">GIN</acronym> index is very compact for cases + where the same key appears many times. + </p><p> + <acronym class="acronym">GIN</acronym> is generalized in the sense that the + <acronym class="acronym">GIN</acronym> access method code does not need to know the + specific operations that it accelerates. + Instead, it uses custom strategies defined for particular data types. + The strategy defines how keys are extracted from indexed items and + query conditions, and how to determine whether a row that contains + some of the key values in a query actually satisfies the query. + </p><p> + One advantage of <acronym class="acronym">GIN</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. + This is much the same advantage as using <acronym class="acronym">GiST</acronym>. + </p><p> + The <acronym class="acronym">GIN</acronym> + implementation in <span class="productname">PostgreSQL</span> is primarily + maintained by Teodor Sigaev and Oleg Bartunov. There is more + information about <acronym class="acronym">GIN</acronym> on their + <a class="ulink" href="http://www.sai.msu.su/~megera/wiki/Gin" target="_top">website</a>. + </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="gin.html" title="Chapter 70. GIN Indexes">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="gin.html" title="Chapter 70. GIN Indexes">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="gin-builtin-opclasses.html" title="70.2. Built-in Operator Classes">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 70. GIN Indexes </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 70.2. Built-in Operator Classes</td></tr></table></div></body></html>
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