doc/src/sgml/ref/show.sgml

   1 <!--
   2 $PostgreSQL$
   3 PostgreSQL documentation
   4 -->
   5
   6 <refentry id="SQL-SHOW">
   7  <refmeta>
   8   <refentrytitle id="SQL-SHOW-TITLE">SHOW</refentrytitle>
   9   <refmiscinfo>SQL - Language Statements</refmiscinfo>
  10  </refmeta>
  11
  12  <refnamediv>
  13   <refname>SHOW</refname>
  14   <refpurpose>show the value of a run-time parameter</refpurpose>
  15  </refnamediv>
  16
  17  <indexterm zone="sql-show">
  18   <primary>SHOW</primary>
  19  </indexterm>
  20
  21  <refsynopsisdiv>
  22 <synopsis>
  23 SHOW <replaceable class="PARAMETER">name</replaceable>
  24 SHOW ALL
  25 </synopsis>
  26  </refsynopsisdiv>
  27
  28  <refsect1>
  29   <title>Description</title>
  30
  31   <para>
  32    <command>SHOW</command> will display the current setting of
  33    run-time parameters. These variables can be set using the
  34    <command>SET</command> statement, by editing the
  35    <filename>postgresql.conf</filename> configuration file, through
  36    the <envar>PGOPTIONS</envar> environmental variable (when using
  37    <application>libpq</> or a <application>libpq</>-based
  38    application), or through command-line flags when starting the
  39    <command>postgres</command> server.  See <xref
  40    linkend="runtime-config"> for details.
  41   </para>
  42  </refsect1>
  43
  44  <refsect1>
  45   <title>Parameters</title>
  46
  47   <variablelist>
  48    <varlistentry>
  49     <term><replaceable class="PARAMETER">name</replaceable></term>
  50     <listitem>
  51      <para>
  52       The name of a run-time parameter.  Available parameters are
  53       documented in <xref linkend="runtime-config"> and on the <xref
  54       linkend="SQL-SET" endterm="SQL-SET-title"> reference page.  In
  55       addition, there are a few parameters that can be shown but not
  56       set:
  57
  58       <variablelist>
  59        <varlistentry>
  60         <term><literal>SERVER_VERSION</literal></term>
  61         <listitem>
  62          <para>
  63           Shows the server's version number.
  64          </para>
  65         </listitem>
  66        </varlistentry>
  67
  68        <varlistentry>
  69         <term><literal>SERVER_ENCODING</literal></term>
  70         <listitem>
  71          <para>
  72           Shows the server-side character set encoding.  At present,
  73           this parameter can be shown but not set, because the
  74           encoding is determined at database creation time.
  75          </para>
  76         </listitem>
  77        </varlistentry>
  78
  79        <varlistentry>
  80         <term><literal>LC_COLLATE</literal></term>
  81         <listitem>
  82          <para>
  83           Shows the database's locale setting for collation (text
  84           ordering).  At present, this parameter can be shown but not
  85           set, because the setting is determined at
  86           <command>initdb</> time.
  87          </para>
  88         </listitem>
  89        </varlistentry>
  90
  91        <varlistentry>
  92         <term><literal>LC_CTYPE</literal></term>
  93         <listitem>
  94          <para>
  95           Shows the database's locale setting for character
  96           classification.  At present, this parameter can be shown but
  97           not set, because the setting is determined at
  98           <command>initdb</> time.
  99          </para>
 100         </listitem>
 101        </varlistentry>
 102
 103        <varlistentry>
 104         <term><literal>IS_SUPERUSER</literal></term>
 105         <listitem>
 106          <para>
 107           True if the current session authorization identifier has
 108           superuser privileges.
 109          </para>
 110         </listitem>
 111        </varlistentry>
 112       </variablelist>
 113      </para>
 114     </listitem>
 115    </varlistentry>
 116
 117    <varlistentry>
 118     <term><literal>ALL</literal></term>
 119     <listitem>
 120      <para>
 121       Show the values of all configuration parameters, with descriptions.
 122      </para>
 123     </listitem>
 124    </varlistentry>
 125   </variablelist>
 126  </refsect1>
 127
 128  <refsect1>
 129   <title>Notes</title>
 130
 131   <para>
 132    The function <function>current_setting</function> produces
 133    equivalent output; see <xref linkend="functions-admin">.
 134    Also, the
 135    <link linkend="view-pg-settings"><structname>pg_settings</structname></link>
 136    system view produces the same information.
 137
 138   </para>
 139  </refsect1>
 140
 141  <refsect1>
 142   <title>Examples</title>
 143
 144   <para>
 145    Show the current setting of the parameter <varname>DateStyle</varname>:
 146
 147 <programlisting>
 148 SHOW DateStyle;
 149  DateStyle
 150 -----------
 151  ISO, MDY
 152 (1 row)
 153 </programlisting>
 154   </para>
 155
 156   <para>
 157    Show the current setting of the parameter <varname>geqo</varname>:
 158 <programlisting>
 159 SHOW geqo;
 160  geqo
 161 ------
 162  on
 163 (1 row)
 164 </programlisting>
 165   </para>
 166
 167   <para>
 168    Show all settings:
 169 <programlisting>
 170 SHOW ALL;
 171               name              |            setting             |                                         description
 172 --------------------------------+--------------------------------+----------------------------------------------------------------------------------------------
 173  add_missing_from               | off                            | Automatically adds missing table references to FROM clauses.
 174  allow_system_table_mods        | off                            | Allows modifications of the structure of system tables.
 175     .
 176     .
 177     .
 178  work_mem                       | 1024                           | Sets the maximum memory to be used for query workspaces.
 179  zero_damaged_pages             | off                            | Continues processing past damaged page headers.
 180 (146 rows)
 181 </programlisting>
 182   </para>
 183  </refsect1>
 184
 185  <refsect1>
 186   <title>Compatibility</title>
 187
 188   <para>
 189    The <command>SHOW</command> command is a
 190    <productname>PostgreSQL</productname> extension.
 191   </para>
 192  </refsect1>
 193
 194  <refsect1>
 195   <title>See Also</title>
 196
 197   <simplelist type="inline">
 198    <member><xref linkend="SQL-SET" endterm="SQL-SET-title"></member>
 199    <member><xref linkend="SQL-RESET" endterm="SQL-RESET-title"></member>
 200   </simplelist>
 201  </refsect1>
 202
 203 </refentry>