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<!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>19.16. Customized Options</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="runtime-config-preset.html" title="19.15. Preset Options" /><link rel="next" href="runtime-config-developer.html" title="19.17. Developer Options" /></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">19.16. Customized Options</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="runtime-config-preset.html" title="19.15. Preset Options">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="runtime-config.html" title="Chapter 19. Server Configuration">Up</a></td><th width="60%" align="center">Chapter 19. Server Configuration</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="runtime-config-developer.html" title="19.17. Developer Options">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="RUNTIME-CONFIG-CUSTOM"><div class="titlepage"><div><div><h2 class="title" style="clear: both">19.16. Customized Options</h2></div></div></div><p>
This feature was designed to allow parameters not normally known to
<span class="productname">PostgreSQL</span> to be added by add-on modules
(such as procedural languages). This allows extension modules to be
configured in the standard ways.
</p><p>
Custom options have two-part names: an extension name, then a dot, then
the parameter name proper, much like qualified names in SQL. An example
is <code class="literal">plpgsql.variable_conflict</code>.
</p><p>
Because custom options may need to be set in processes that have not
loaded the relevant extension module, <span class="productname">PostgreSQL</span>
will accept a setting for any two-part parameter name. Such variables
are treated as placeholders and have no function until the module that
defines them is loaded. When an extension module is loaded, it will add
its variable definitions, convert any placeholder values according to
those definitions, and issue warnings for any unrecognized placeholders
that begin with its extension name.
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