doc/src/sgml/ref/reset.sgml

   1 <!--
   2 $PostgreSQL$
   3 PostgreSQL documentation
   4 -->
   5
   6 <refentry id="SQL-RESET">
   7  <refmeta>
   8   <refentrytitle id="SQL-RESET-TITLE">RESET</refentrytitle>
   9   <manvolnum>7</manvolnum>
  10   <refmiscinfo>SQL - Language Statements</refmiscinfo>
  11  </refmeta>
  12
  13  <refnamediv>
  14   <refname>RESET</refname>
  15   <refpurpose>restore the value of a run-time parameter to the default value</refpurpose>
  16  </refnamediv>
  17
  18  <indexterm zone="sql-reset">
  19   <primary>RESET</primary>
  20  </indexterm>
  21
  22  <refsynopsisdiv>
  23 <synopsis>
  24 RESET <replaceable class="PARAMETER">configuration_parameter</replaceable>
  25 RESET ALL
  26 </synopsis>
  27  </refsynopsisdiv>
  28
  29  <refsect1>
  30   <title>Description</title>
  31
  32   <para>
  33    <command>RESET</command> restores run-time parameters to their
  34    default values.  <command>RESET</command> is an alternative
  35    spelling for
  36 <synopsis>
  37 SET <replaceable class="parameter">configuration_parameter</replaceable> TO DEFAULT
  38 </synopsis>
  39    Refer to <xref linkend="sql-set" endterm="sql-set-title"> for
  40    details.
  41   </para>
  42
  43   <para>
  44    The default value is defined as the value that the parameter would
  45    have had, if no <command>SET</> had ever been issued for it in the
  46    current session.  The actual source of this value might be a
  47    compiled-in default, the configuration file, command-line options,
  48    or per-database or per-user default settings.  This is subtly different
  49    from defining it as <quote>the value that the parameter had at session
  50    start</>, because if the value came from the configuration file, it
  51    will be reset to whatever is specified by the configuration file now.
  52    See <xref linkend="runtime-config"> for details.
  53   </para>
  54
  55   <para>
  56    The transactional behavior of <command>RESET</> is the same as
  57    <command>SET</>: its effects will be undone by transaction rollback.
  58   </para>
  59  </refsect1>
  60
  61  <refsect1>
  62   <title>Parameters</title>
  63
  64   <variablelist>
  65    <varlistentry>
  66     <term><replaceable class="PARAMETER">configuration_parameter</replaceable></term>
  67     <listitem>
  68      <para>
  69       Name of a settable run-time parameter.  Available parameters are
  70       documented in <xref linkend="runtime-config"> and on the
  71       <xref linkend="sql-set" endterm="sql-set-title"> reference page.
  72      </para>
  73     </listitem>
  74    </varlistentry>
  75
  76    <varlistentry>
  77     <term><literal>ALL</literal></term>
  78     <listitem>
  79      <para>
  80       Resets all settable run-time parameters to default values.
  81      </para>
  82     </listitem>
  83    </varlistentry>
  84   </variablelist>
  85  </refsect1>
  86
  87  <refsect1>
  88   <title>Examples</title>
  89
  90   <para>
  91    Set the <varname>timezone</> configuration variable to its default value:
  92 <screen>
  93 RESET timezone;
  94 </screen>
  95   </para>
  96  </refsect1>
  97
  98  <refsect1>
  99   <title>Compatibility</title>
 100
 101   <para>
 102    <command>RESET</command> is a <productname>PostgreSQL</productname> extension.
 103   </para>
 104  </refsect1>
 105
 106  <refsect1>
 107   <title>See Also</title>
 108
 109   <simplelist type="inline">
 110    <member><xref linkend="SQL-SET" endterm="SQL-SET-title"></member>
 111    <member><xref linkend="SQL-SHOW" endterm="SQL-SHOW-title"></member>
 112   </simplelist>
 113  </refsect1>
 114 </refentry>