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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>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><div xmlns="http://www.w3.org/TR/xhtml1/transitional" 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 11.5 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></hr></div><div class="refentry" id="SQL-SET"><div class="titlepage"></div><a id="id-1.9.3.173.1" 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>timezone</code></em> | LOCAL | DEFAULT }
</pre></div><div class="refsect1" id="id-1.9.3.173.5"><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 19. Server Configuration">Chapter 19</a> can be changed on-the-fly with
<code class="command">SET</code>.
(But some require superuser privileges to change, and others 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-1.9.3.173.6"><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 19. Server Configuration">Chapter 19</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 19. Server Configuration">Chapter 19</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, which are then
multiplied by 2<sup>31</sup>-1.
</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"><-07>+07</code>.
</p><p>
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-1.9.3.173.7"><h2>Notes</h2><p>
The function <code class="function">set_config</code> provides equivalent
functionality; see <a class="xref" href="functions-admin.html" title="9.26. System Administration Functions">Section 9.26</a>.
Also, it is possible to UPDATE the
<a class="link" href="view-pg-settings.html" title="52.85. 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-1.9.3.173.8"><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-1.9.3.173.9"><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-1.9.3.173.10"><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">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-set-constraints.html">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">Home</a></td><td width="40%" align="right" valign="top"> SET CONSTRAINTS</td></tr></table></div></body></html>
