<?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>66.6. Limitations</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-tips.html" title="66.5. GIN Tips and Tricks" /><link rel="next" href="gin-examples.html" title="66.7. Examples" /></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">66.6. Limitations</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="gin-tips.html" title="66.5. GIN Tips and Tricks">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="gin.html" title="Chapter 66. GIN Indexes">Up</a></td><th width="60%" align="center">Chapter 66. GIN Indexes</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="gin-examples.html" title="66.7. Examples">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="GIN-LIMIT"><div class="titlepage"><div><div><h2 class="title" style="clear: both">66.6. Limitations</h2></div></div></div><p> <acronym class="acronym">GIN</acronym> assumes that indexable operators are strict. This means that <code class="function">extractValue</code> will not be called at all on a null item value (instead, a placeholder index entry is created automatically), and <code class="function">extractQuery</code> will not be called on a null query value either (instead, the query is presumed to be unsatisfiable). Note however that null key values contained within a non-null composite item or query value are supported. </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="gin-tips.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="gin.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="gin-examples.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">66.5. GIN Tips and Tricks </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 66.7. Examples</td></tr></table></div></body></html>
