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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 13:44:03 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 13:44:03 +0000
commit293913568e6a7a86fd1479e1cff8e2ecb58d6568 (patch)
treefc3b469a3ec5ab71b36ea97cc7aaddb838423a0c /doc/src/sgml/html/sql-set.html
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downloadpostgresql-16-293913568e6a7a86fd1479e1cff8e2ecb58d6568.tar.xz
postgresql-16-293913568e6a7a86fd1479e1cff8e2ecb58d6568.zip
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Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+<?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>SET</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="sql-selectinto.html" title="SELECT INTO" /><link rel="next" href="sql-set-constraints.html" title="SET CONSTRAINTS" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">SET</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-selectinto.html" title="SELECT INTO">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</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="sql-set-constraints.html" title="SET CONSTRAINTS">Next</a></td></tr></table><hr /></div><div class="refentry" id="SQL-SET"><div class="titlepage"></div><a id="id-1.9.3.174.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">SET</span></h2><p>SET — change a run-time parameter</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">
+SET [ SESSION | LOCAL ] <em class="replaceable"><code>configuration_parameter</code></em> { TO | = } { <em class="replaceable"><code>value</code></em> | '<em class="replaceable"><code>value</code></em>' | DEFAULT }
+SET [ SESSION | LOCAL ] TIME ZONE { <em class="replaceable"><code>value</code></em> | '<em class="replaceable"><code>value</code></em>' | LOCAL | DEFAULT }
+</pre></div><div class="refsect1" id="id-1.9.3.174.5"><h2>Description</h2><p>
+ The <code class="command">SET</code> command changes run-time configuration
+ parameters. Many of the run-time parameters listed in
+ <a class="xref" href="runtime-config.html" title="Chapter 20. Server Configuration">Chapter 20</a> can be changed on-the-fly with
+ <code class="command">SET</code>.
+ (Some parameters can only be changed by superusers and users who
+ have been granted <code class="literal">SET</code> privilege on that parameter.
+ There are also parameters that cannot be changed after server or
+ session start.)
+ <code class="command">SET</code> only affects the value used by the current
+ session.
+ </p><p>
+ If <code class="command">SET</code> (or equivalently <code class="command">SET SESSION</code>)
+ is issued within a transaction that is later aborted, the effects of the
+ <code class="command">SET</code> command disappear when the transaction is rolled
+ back. Once the surrounding transaction is committed, the effects
+ will persist until the end of the session, unless overridden by another
+ <code class="command">SET</code>.
+ </p><p>
+ The effects of <code class="command">SET LOCAL</code> last only till the end of
+ the current transaction, whether committed or not. A special case is
+ <code class="command">SET</code> followed by <code class="command">SET LOCAL</code> within
+ a single transaction: the <code class="command">SET LOCAL</code> value will be
+ seen until the end of the transaction, but afterwards (if the transaction
+ is committed) the <code class="command">SET</code> value will take effect.
+ </p><p>
+ The effects of <code class="command">SET</code> or <code class="command">SET LOCAL</code> are
+ also canceled by rolling back to a savepoint that is earlier than the
+ command.
+ </p><p>
+ If <code class="command">SET LOCAL</code> is used within a function that has a
+ <code class="literal">SET</code> option for the same variable (see
+ <a class="xref" href="sql-createfunction.html" title="CREATE FUNCTION"><span class="refentrytitle">CREATE FUNCTION</span></a>),
+ the effects of the <code class="command">SET LOCAL</code> command disappear at
+ function exit; that is, the value in effect when the function was called is
+ restored anyway. This allows <code class="command">SET LOCAL</code> to be used for
+ dynamic or repeated changes of a parameter within a function, while still
+ having the convenience of using the <code class="literal">SET</code> option to save and
+ restore the caller's value. However, a regular <code class="command">SET</code> command
+ overrides any surrounding function's <code class="literal">SET</code> option; its effects
+ will persist unless rolled back.
+ </p><div class="note"><h3 class="title">Note</h3><p>
+ In <span class="productname">PostgreSQL</span> versions 8.0 through 8.2,
+ the effects of a <code class="command">SET LOCAL</code> would be canceled by
+ releasing an earlier savepoint, or by successful exit from a
+ <span class="application">PL/pgSQL</span> exception block. This behavior
+ has been changed because it was deemed unintuitive.
+ </p></div></div><div class="refsect1" id="id-1.9.3.174.6"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">SESSION</code></span></dt><dd><p>
+ Specifies that the command takes effect for the current session.
+ (This is the default if neither <code class="literal">SESSION</code> nor
+ <code class="literal">LOCAL</code> appears.)
+ </p></dd><dt><span class="term"><code class="literal">LOCAL</code></span></dt><dd><p>
+ Specifies that the command takes effect for only the current
+ transaction. After <code class="command">COMMIT</code> or <code class="command">ROLLBACK</code>,
+ the session-level setting takes effect again. Issuing this
+ outside of a transaction block emits a warning and otherwise has
+ no effect.
+ </p></dd><dt><span class="term"><em class="replaceable"><code>configuration_parameter</code></em></span></dt><dd><p>
+ Name of a settable run-time parameter. Available parameters are
+ documented in <a class="xref" href="runtime-config.html" title="Chapter 20. Server Configuration">Chapter 20</a> and below.
+ </p></dd><dt><span class="term"><em class="replaceable"><code>value</code></em></span></dt><dd><p>
+ New value of parameter. Values can be specified as string
+ constants, identifiers, numbers, or comma-separated lists of
+ these, as appropriate for the particular parameter.
+ <code class="literal">DEFAULT</code> can be written to specify
+ resetting the parameter to its default value (that is, whatever
+ value it would have had if no <code class="command">SET</code> had been executed
+ in the current session).
+ </p></dd></dl></div><p>
+ Besides the configuration parameters documented in <a class="xref" href="runtime-config.html" title="Chapter 20. Server Configuration">Chapter 20</a>, there are a few that can only be
+ adjusted using the <code class="command">SET</code> command or that have a
+ special syntax:
+
+ </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">SCHEMA</code></span></dt><dd><p><code class="literal">SET SCHEMA '<em class="replaceable"><code>value</code></em>'</code> is an alias for
+ <code class="literal">SET search_path TO <em class="replaceable"><code>value</code></em></code>. Only one
+ schema can be specified using this syntax.
+ </p></dd><dt><span class="term"><code class="literal">NAMES</code></span></dt><dd><p><code class="literal">SET NAMES <em class="replaceable"><code>value</code></em></code> is an alias for
+ <code class="literal">SET client_encoding TO <em class="replaceable"><code>value</code></em></code>.
+ </p></dd><dt><span class="term"><code class="literal">SEED</code></span></dt><dd><p>
+ Sets the internal seed for the random number generator (the
+ function <code class="function">random</code>). Allowed values are
+ floating-point numbers between -1 and 1 inclusive.
+ </p><p>
+ The seed can also be set by invoking the function
+ <code class="function">setseed</code>:
+</p><pre class="programlisting">
+SELECT setseed(<em class="replaceable"><code>value</code></em>);
+</pre></dd><dt><span class="term"><code class="literal">TIME ZONE</code></span></dt><dd><p><code class="literal">SET TIME ZONE '<em class="replaceable"><code>value</code></em>'</code> is an alias
+ for <code class="literal">SET timezone TO '<em class="replaceable"><code>value</code></em>'</code>. The
+ syntax <code class="literal">SET TIME ZONE</code> allows special syntax
+ for the time zone specification. Here are examples of valid
+ values:
+
+ </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">'PST8PDT'</code></span></dt><dd><p>
+ The time zone for Berkeley, California.
+ </p></dd><dt><span class="term"><code class="literal">'Europe/Rome'</code></span></dt><dd><p>
+ The time zone for Italy.
+ </p></dd><dt><span class="term"><code class="literal">-7</code></span></dt><dd><p>
+ The time zone 7 hours west from UTC (equivalent
+ to PDT). Positive values are east from UTC.
+ </p></dd><dt><span class="term"><code class="literal">INTERVAL '-08:00' HOUR TO MINUTE</code></span></dt><dd><p>
+ The time zone 8 hours west from UTC (equivalent
+ to PST).
+ </p></dd><dt><span class="term"><code class="literal">LOCAL</code><br /></span><span class="term"><code class="literal">DEFAULT</code></span></dt><dd><p>
+ Set the time zone to your local time zone (that is, the
+ server's default value of <code class="varname">timezone</code>).
+ </p></dd></dl></div><p>
+ </p><p>
+ Timezone settings given as numbers or intervals are internally
+ translated to POSIX timezone syntax. For example, after
+ <code class="literal">SET TIME ZONE -7</code>, <code class="command">SHOW TIME ZONE</code> would
+ report <code class="literal">&lt;-07&gt;+07</code>.
+ </p><p>
+ Time zone abbreviations are not supported by <code class="command">SET</code>;
+ see <a class="xref" href="datatype-datetime.html#DATATYPE-TIMEZONES" title="8.5.3. Time Zones">Section 8.5.3</a> for more information
+ about time zones.
+ </p></dd></dl></div><p>
+ </p></div><div class="refsect1" id="id-1.9.3.174.7"><h2>Notes</h2><p>
+ The function <code class="function">set_config</code> provides equivalent
+ functionality; see <a class="xref" href="functions-admin.html#FUNCTIONS-ADMIN-SET" title="9.27.1. Configuration Settings Functions">Section 9.27.1</a>.
+ Also, it is possible to UPDATE the
+ <a class="link" href="view-pg-settings.html" title="54.24. pg_settings"><code class="structname">pg_settings</code></a>
+ system view to perform the equivalent of <code class="command">SET</code>.
+ </p></div><div class="refsect1" id="id-1.9.3.174.8"><h2>Examples</h2><p>
+ Set the schema search path:
+</p><pre class="programlisting">
+SET search_path TO my_schema, public;
+</pre><p>
+ </p><p>
+ Set the style of date to traditional
+ <span class="productname">POSTGRES</span> with <span class="quote">“<span class="quote">day before month</span>”</span>
+ input convention:
+</p><pre class="screen">
+SET datestyle TO postgres, dmy;
+</pre><p>
+ </p><p>
+ Set the time zone for Berkeley, California:
+</p><pre class="screen">
+SET TIME ZONE 'PST8PDT';
+</pre><p>
+ </p><p>
+ Set the time zone for Italy:
+</p><pre class="screen">
+SET TIME ZONE 'Europe/Rome';
+</pre></div><div class="refsect1" id="id-1.9.3.174.9"><h2>Compatibility</h2><p>
+ <code class="literal">SET TIME ZONE</code> extends syntax defined in the SQL
+ standard. The standard allows only numeric time zone offsets while
+ <span class="productname">PostgreSQL</span> allows more flexible
+ time-zone specifications. All other <code class="literal">SET</code>
+ features are <span class="productname">PostgreSQL</span> extensions.
+ </p></div><div class="refsect1" id="id-1.9.3.174.10"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-reset.html" title="RESET"><span class="refentrytitle">RESET</span></a>, <a class="xref" href="sql-show.html" title="SHOW"><span class="refentrytitle">SHOW</span></a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sql-selectinto.html" title="SELECT INTO">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-set-constraints.html" title="SET CONSTRAINTS">Next</a></td></tr><tr><td width="40%" align="left" valign="top">SELECT INTO </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"> SET CONSTRAINTS</td></tr></table></div></body></html> \ No newline at end of file
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