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doc/src/sgml/ref/pg_ctl-ref.sgml
PostgreSQL documentation
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<refentry id="app-pg-ctl">
 <indexterm zone="app-pg-ctl">
  <primary>pg_ctl</primary>
 </indexterm>

 <refmeta>
  <refentrytitle><application>pg_ctl</application></refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo>Application</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>pg_ctl</refname>
  <refpurpose>initialize, start, stop, or control a <productname>PostgreSQL</productname> server</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
  <cmdsynopsis>
   <command>pg_ctl</command>
   <arg choice="plain"><option>init[db]</option></arg>
   <arg choice="opt"><option>-D</option> <replaceable>datadir</replaceable></arg>
   <arg choice="opt"><option>-s</option></arg>
   <arg choice="opt"><option>-o</option> <replaceable>initdb-options</replaceable></arg>
  </cmdsynopsis>

  <cmdsynopsis>
   <command>pg_ctl</command>
   <arg choice="plain"><option>start</option></arg>
   <arg choice="opt"><option>-D</option> <replaceable>datadir</replaceable></arg>
   <arg choice="opt"><option>-l</option> <replaceable>filename</replaceable></arg>
   <arg choice="opt"><option>-W</option></arg>
   <arg choice="opt"><option>-t</option> <replaceable>seconds</replaceable></arg>
   <arg choice="opt"><option>-s</option></arg>
   <arg choice="opt"><option>-o</option> <replaceable>options</replaceable></arg>
   <arg choice="opt"><option>-p</option> <replaceable>path</replaceable></arg>
   <arg choice="opt"><option>-c</option></arg>
  </cmdsynopsis>

  <cmdsynopsis>
   <command>pg_ctl</command>
   <arg choice="plain"><option>stop</option></arg>
   <arg choice="opt"><option>-D</option> <replaceable>datadir</replaceable></arg>
   <arg choice="opt"><option>-m</option>
     <group choice="plain">
       <arg choice="plain"><option>s[mart]</option></arg>
       <arg choice="plain"><option>f[ast]</option></arg>
       <arg choice="plain"><option>i[mmediate]</option></arg>
     </group>
   </arg>
   <arg choice="opt"><option>-W</option></arg>
   <arg choice="opt"><option>-t</option> <replaceable>seconds</replaceable></arg>
   <arg choice="opt"><option>-s</option></arg>
  </cmdsynopsis>

  <cmdsynopsis>
   <command>pg_ctl</command>
   <arg choice="plain"><option>restart</option></arg>
   <arg choice="opt"><option>-D</option> <replaceable>datadir</replaceable></arg>
   <arg choice="opt"><option>-m</option>
     <group choice="plain">
       <arg choice="plain"><option>s[mart]</option></arg>
       <arg choice="plain"><option>f[ast]</option></arg>
       <arg choice="plain"><option>i[mmediate]</option></arg>
     </group>
   </arg>
   <arg choice="opt"><option>-W</option></arg>
   <arg choice="opt"><option>-t</option> <replaceable>seconds</replaceable></arg>
   <arg choice="opt"><option>-s</option></arg>
   <arg choice="opt"><option>-o</option> <replaceable>options</replaceable></arg>
   <arg choice="opt"><option>-c</option></arg>
  </cmdsynopsis>

  <cmdsynopsis>
   <command>pg_ctl</command>
   <arg choice="plain"><option>reload</option></arg>
   <arg choice="opt"><option>-D</option> <replaceable>datadir</replaceable></arg>
   <arg choice="opt"><option>-s</option></arg>
  </cmdsynopsis>

  <cmdsynopsis>
   <command>pg_ctl</command>
   <arg choice="plain"><option>status</option></arg>
   <arg choice="opt"><option>-D</option> <replaceable>datadir</replaceable></arg>
  </cmdsynopsis>

  <cmdsynopsis>
   <command>pg_ctl</command>
   <arg choice="plain"><option>promote</option></arg>
   <arg choice="opt"><option>-D</option> <replaceable>datadir</replaceable></arg>
   <arg choice="opt"><option>-W</option></arg>
   <arg choice="opt"><option>-t</option> <replaceable>seconds</replaceable></arg>
   <arg choice="opt"><option>-s</option></arg>
  </cmdsynopsis>

  <cmdsynopsis>
   <command>pg_ctl</command>
   <arg choice="plain"><option>kill</option></arg>
   <arg choice="plain"><replaceable>signal_name</replaceable></arg>
   <arg choice="plain"><replaceable>process_id</replaceable></arg>
  </cmdsynopsis>

  <para>On Microsoft Windows, also:</para>

  <cmdsynopsis>
   <command>pg_ctl</command>
   <arg choice="plain"><option>register</option></arg>
   <arg choice="opt"><option>-D</option> <replaceable>datadir</replaceable></arg>
   <arg choice="opt"><option>-N</option> <replaceable>servicename</replaceable></arg>
   <arg choice="opt"><option>-U</option> <replaceable>username</replaceable></arg>
   <arg choice="opt"><option>-P</option> <replaceable>password</replaceable></arg>
   <arg choice="opt"><option>-S</option>
     <group choice="plain">
       <arg choice="plain"><option>a[uto]</option></arg>
       <arg choice="plain"><option>d[emand]</option></arg>
     </group>
   </arg>
   <arg choice="opt"><option>-e</option> <replaceable>source</replaceable></arg>
   <arg choice="opt"><option>-W</option></arg>
   <arg choice="opt"><option>-t</option> <replaceable>seconds</replaceable></arg>
   <arg choice="opt"><option>-s</option></arg>
   <arg choice="opt"><option>-o</option> <replaceable>options</replaceable></arg>
  </cmdsynopsis>

  <cmdsynopsis>
   <command>pg_ctl</command>
   <arg choice="plain"><option>unregister</option></arg>
   <arg choice="opt"><option>-N</option> <replaceable>servicename</replaceable></arg>
  </cmdsynopsis>
 </refsynopsisdiv>


 <refsect1 id="app-pg-ctl-description">
  <title>Description</title>
  <para>
   <application>pg_ctl</application> is a utility for initializing a
   <productname>PostgreSQL</productname> database cluster, starting,
   stopping, or restarting the <productname>PostgreSQL</productname>
   database server (<xref linkend="app-postgres"/>), or displaying the
   status of a running server.  Although the server can be started
   manually, <application>pg_ctl</application> encapsulates tasks such
   as redirecting log output and properly detaching from the terminal
   and process group. It also provides convenient options for
   controlled shutdown.
  </para>

  <para>
   The <option>init</option> or <option>initdb</option> mode creates a new
   <productname>PostgreSQL</productname> database cluster, that is,
   a collection of databases that will be managed by a single
   server instance.  This mode invokes the <command>initdb</command>
   command.  See <xref linkend="app-initdb"/> for details.
  </para>

  <para>
   <option>start</option> mode launches a new server.  The
   server is started in the background, and its standard input is attached
   to <filename>/dev/null</filename> (or <literal>nul</literal> on Windows).
   On Unix-like systems, by default, the server's standard output and
   standard error are sent to <application>pg_ctl</application>'s
   standard output (not standard error).  The standard output of
   <application>pg_ctl</application> should then be redirected to a
   file or piped to another process such as a log rotating program
   like <application>rotatelogs</application>; otherwise <command>postgres</command>
   will write its output to the controlling terminal (from the
   background) and will not leave the shell's process group.  On
   Windows, by default the server's standard output and standard error
   are sent to the terminal.  These default behaviors can be changed
   by using <option>-l</option> to append the server's output to a log file.
   Use of either <option>-l</option> or output redirection is recommended.
  </para>

  <para>
   <option>stop</option> mode shuts down the server that is running in
   the specified data directory.  Three different
   shutdown methods can be selected with the <option>-m</option>
   option.  <quote>Smart</quote> mode disallows new connections, then waits
   for all existing clients to disconnect and any online backup to finish.
   If the server is in hot standby, recovery and streaming replication
   will be terminated once all clients have disconnected.
   <quote>Fast</quote> mode (the default) does not wait for clients to disconnect and
   will terminate an online backup in progress.  All active transactions are
   rolled back and clients are forcibly disconnected, then the
   server is shut down.  <quote>Immediate</quote> mode will abort
   all server processes immediately, without a clean shutdown.  This choice
   will lead to a crash-recovery cycle during the next server start.
  </para>

  <para>
   <option>restart</option> mode effectively executes a stop followed
   by a start.  This allows changing the <command>postgres</command>
   command-line options, or changing configuration-file options that
   cannot be changed without restarting the server.
   If relative paths were used on the command line during server
   start, <option>restart</option> might fail unless
   <application>pg_ctl</application> is executed in the same current
   directory as it was during server start.
  </para>

  <para>
   <option>reload</option> mode simply sends the
   <command>postgres</command> server process a <systemitem>SIGHUP</systemitem>
   signal, causing it to reread its configuration files
   (<filename>postgresql.conf</filename>,
   <filename>pg_hba.conf</filename>, etc.).  This allows changing
   configuration-file options that do not require a full server restart
   to take effect.
  </para>

  <para>
   <option>status</option> mode checks whether a server is running in
   the specified data directory. If it is, the server's <acronym>PID</acronym>
   and the command line options that were used to invoke it are displayed.
   If the server is not running, <application>pg_ctl</application> returns
   an exit status of 3.  If an accessible data directory is not
   specified, <application>pg_ctl</application> returns an exit status of 4.
  </para>

  <para>
   <option>promote</option> mode commands the standby server that is
   running in the specified data directory to end standby mode
   and begin read-write operations.
  </para>

  <para>
   <option>kill</option> mode sends a signal to a specified process.
   This is primarily valuable on <productname>Microsoft Windows</productname>
   which does not have a built-in <application>kill</application> command.  Use
   <literal>--help</literal> to see a list of supported signal names.
  </para>

  <para>
   <option>register</option> mode registers the <productname>PostgreSQL</productname>
   server as a system service on <productname>Microsoft Windows</productname>.
   The <option>-S</option> option allows selection of service start type,
   either <quote>auto</quote> (start service automatically on system startup)
   or <quote>demand</quote> (start service on demand).
  </para>

  <para>
   <option>unregister</option> mode unregisters a system service
   on <productname>Microsoft Windows</productname>.  This undoes the effects of the
   <option>register</option> command.
  </para>
 </refsect1>

 <refsect1 id="app-pg-ctl-options">
  <title>Options</title>

    <variablelist>

     <varlistentry>
      <term><option>-c</option></term>
      <term><option>--core-files</option></term>
      <listitem>
       <para>
        Attempt to allow server crashes to produce core files, on platforms
        where this is possible, by lifting any soft resource limit placed on
        core files.
        This is useful in debugging or diagnosing problems by allowing a
        stack trace to be obtained from a failed server process.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-D <replaceable class="parameter">datadir</replaceable></option></term>
      <term><option>--pgdata=<replaceable class="parameter">datadir</replaceable></option></term>
      <listitem>
       <para>
        Specifies the file system location of the database configuration files.  If
        this option is omitted, the environment variable
        <envar>PGDATA</envar> is used.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-l <replaceable class="parameter">filename</replaceable></option></term>
      <term><option>--log=<replaceable class="parameter">filename</replaceable></option></term>
      <listitem>
       <para>
        Append the server log output to
        <replaceable>filename</replaceable>.  If the file does not
        exist, it is created.  The <systemitem>umask</systemitem> is set to 077,
        so access to the log file is disallowed to other users by default.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-m <replaceable class="parameter">mode</replaceable></option></term>
      <term><option>--mode=<replaceable class="parameter">mode</replaceable></option></term>
      <listitem>
       <para>
        Specifies the shutdown mode.  <replaceable>mode</replaceable>
        can be <literal>smart</literal>, <literal>fast</literal>, or
        <literal>immediate</literal>, or the first letter of one of
        these three.  If this option is omitted, <literal>fast</literal> is
        the default.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-o <replaceable class="parameter">options</replaceable></option></term>
      <term><option>--options=<replaceable class="parameter">options</replaceable></option></term>
      <listitem>
       <para>
        Specifies options to be passed directly to the
        <command>postgres</command> command.
        <option>-o</option> can be specified multiple times, with all the given
        options being passed through.
       </para>
       <para>
        The <replaceable>options</replaceable> should usually be surrounded by single or
        double quotes to ensure that they are passed through as a group.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-o <replaceable class="parameter">initdb-options</replaceable></option></term>
      <term><option>--options=<replaceable class="parameter">initdb-options</replaceable></option></term>
      <listitem>
       <para>
        Specifies options to be passed directly to the
        <command>initdb</command> command.
        <option>-o</option> can be specified multiple times, with all the given
        options being passed through.
       </para>
       <para>
        The <replaceable>initdb-options</replaceable> should usually be surrounded by single or
        double quotes to ensure that they are passed through as a group.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-p <replaceable class="parameter">path</replaceable></option></term>
      <listitem>
       <para>
        Specifies the location of the <filename>postgres</filename>
        executable.  By default the <filename>postgres</filename> executable is taken from the same
        directory as <command>pg_ctl</command>, or failing that, the hard-wired
        installation directory.  It is not necessary to use this
        option unless you are doing something unusual and get errors
        that the <filename>postgres</filename> executable was not found.
       </para>

       <para>
        In <literal>init</literal> mode, this option analogously
        specifies the location of the <filename>initdb</filename>
        executable.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-s</option></term>
      <term><option>--silent</option></term>
      <listitem>
       <para>
        Print only errors, no informational messages.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-t <replaceable class="parameter">seconds</replaceable></option></term>
      <term><option>--timeout=<replaceable class="parameter">seconds</replaceable></option></term>
      <listitem>
       <para>
        Specifies the maximum number of seconds to wait when waiting for an
        operation to complete (see option <option>-w</option>).  Defaults to
        the value of the <envar>PGCTLTIMEOUT</envar> environment variable or, if
        not set, to 60 seconds.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-V</option></term>
      <term><option>--version</option></term>
       <listitem>
        <para>
         Print the <application>pg_ctl</application> version and exit.
        </para>
       </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-w</option></term>
      <term><option>--wait</option></term>
      <listitem>
       <para>
        Wait for the operation to complete.  This is supported for the
        modes <literal>start</literal>, <literal>stop</literal>,
        <literal>restart</literal>, <literal>promote</literal>,
        and <literal>register</literal>, and is the default for those modes.
       </para>

       <para>
        When waiting, <command>pg_ctl</command> repeatedly checks the
        server's <acronym>PID</acronym> file, sleeping for a short amount
        of time between checks.  Startup is considered complete when
        the <acronym>PID</acronym> file indicates that the server is ready to
        accept connections.  Shutdown is considered complete when the server
        removes the <acronym>PID</acronym> file.
        <command>pg_ctl</command> returns an exit code based on the
        success of the startup or shutdown.
       </para>

       <para>
        If the operation does not complete within the timeout (see
        option <option>-t</option>), then <command>pg_ctl</command> exits with
        a nonzero exit status.  But note that the operation might continue in
        the background and eventually succeed.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-W</option></term>
      <term><option>--no-wait</option></term>
      <listitem>
       <para>
        Do not wait for the operation to complete.  This is the opposite of
        the option <option>-w</option>.
       </para>

       <para>
        If waiting is disabled, the requested action is triggered, but there
        is no feedback about its success.  In that case, the server log file
        or an external monitoring system would have to be used to check the
        progress and success of the operation.
       </para>

       <para>
        In prior releases of PostgreSQL, this was the default except for
        the <literal>stop</literal> mode.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-?</option></term>
      <term><option>--help</option></term>
      <listitem>
       <para>
        Show help about <application>pg_ctl</application> command line
        arguments, and exit.
       </para>
      </listitem>
     </varlistentry>
   </variablelist>

  <para>
   If an option is specified that is valid, but not relevant to the selected
   operating mode, <application>pg_ctl</application> ignores it.
  </para>

  <refsect2 id="app-pg-ctl-windows-options">
   <title>Options for Windows</title>

   <variablelist>
    <varlistentry>
     <term><option>-e <replaceable class="parameter">source</replaceable></option></term>
     <listitem>
      <para>
       Name of the event source for <application>pg_ctl</application> to use
       for logging to the event log when running as a Windows service.  The
       default is <literal>PostgreSQL</literal>.  Note that this only controls
       messages sent from <application>pg_ctl</application> itself; once
       started, the server will use the event source specified
       by its <xref linkend="guc-event-source"/> parameter.  Should the server
       fail very early in startup, before that parameter has been set,
       it might also log using the default event
       source name <literal>PostgreSQL</literal>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-N <replaceable class="parameter">servicename</replaceable></option></term>
     <listitem>
      <para>
       Name of the system service to register. This name will be used
       as both the service name and the display name.
       The default is <literal>PostgreSQL</literal>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-P <replaceable class="parameter">password</replaceable></option></term>
     <listitem>
      <para>
       Password for the user to run the service as.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-S <replaceable class="parameter">start-type</replaceable></option></term>
     <listitem>
      <para>
       Start type of the system service.  <replaceable>start-type</replaceable> can
       be <literal>auto</literal>, or <literal>demand</literal>, or
       the first letter of one of these two. If this option is omitted,
       <literal>auto</literal> is the default.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><option>-U <replaceable class="parameter">username</replaceable></option></term>
     <listitem>
      <para>
       User name for the user to run the service as. For domain users, use the
       format <literal>DOMAIN\username</literal>.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </refsect2>

 </refsect1>


 <refsect1>
  <title>Environment</title>

  <variablelist>
   <varlistentry>
    <term><envar>PGCTLTIMEOUT</envar></term>

    <listitem>
     <para>
      Default limit on the number of seconds to wait when waiting for startup
      or shutdown to complete.  If not set, the default is 60 seconds.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><envar>PGDATA</envar></term>

    <listitem>
     <para>
      Default data directory location.
     </para>
    </listitem>
   </varlistentry>

  </variablelist>

  <para>
   Most <command>pg_ctl</command> modes require knowing the data directory
   location; therefore, the <option>-D</option> option is required
   unless <envar>PGDATA</envar> is set.
  </para>

  <para>
   <command>pg_ctl</command>, like most other <productname>PostgreSQL</productname>
   utilities,
   also uses the environment variables supported by <application>libpq</application>
   (see <xref linkend="libpq-envars"/>).
  </para>

  <para>
   For additional variables that affect the server,
   see <xref linkend="app-postgres"/>.
  </para>
 </refsect1>


 <refsect1>
  <title>Files</title>

  <variablelist>
   <varlistentry>
    <term><filename>postmaster.pid</filename></term>

    <listitem>
     <para>
      <application>pg_ctl</application> examines this file in the data
      directory to determine whether the server is currently running.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><filename>postmaster.opts</filename></term>

    <listitem>
     <para>If this file exists in the data directory,
      <application>pg_ctl</application> (in <option>restart</option> mode)
      will pass the contents of the file as options to
      <application>postgres</application>, unless overridden
      by the <option>-o</option> option. The contents of this file
      are also displayed in <option>status</option> mode.
     </para>
    </listitem>
   </varlistentry>

  </variablelist>
 </refsect1>


 <refsect1 id="r1-app-pgctl-2">
  <title>Examples</title>

  <refsect2 id="r2-app-pgctl-3">
   <title>Starting the Server</title>

   <para>
    To start the server, waiting until the server is
    accepting connections:
<screen>
<prompt>$</prompt> <userinput>pg_ctl start</userinput>
</screen>
   </para>

   <para>
    To start the server using port 5433, and
    running without <function>fsync</function>, use:
<screen>
<prompt>$</prompt> <userinput>pg_ctl -o "-F -p 5433" start</userinput>
</screen></para>
  </refsect2>

  <refsect2 id="r2-app-pgctl-4">
   <title>Stopping the Server</title>
   <para>
    To stop the server, use:
<screen>
<prompt>$</prompt> <userinput>pg_ctl stop</userinput>
</screen>
    The <option>-m</option> option allows control over
    <emphasis>how</emphasis> the server shuts down:
<screen>
<prompt>$</prompt> <userinput>pg_ctl stop -m smart</userinput>
</screen></para>
  </refsect2>

  <refsect2 id="r2-app-pgctl-5">
   <title>Restarting the Server</title>

   <para>
    Restarting the server is almost equivalent to stopping the
    server and starting it again, except that by default,
    <command>pg_ctl</command> saves and reuses the command line options that
    were passed to the previously-running instance.  To restart
    the server using the same options as before, use:
<screen>
<prompt>$</prompt> <userinput>pg_ctl restart</userinput>
</screen>
   </para>

   <para>
    But if <option>-o</option> is specified, that replaces any previous options.
    To restart using port 5433, disabling <function>fsync</function> upon restart:
<screen>
<prompt>$</prompt> <userinput>pg_ctl -o "-F -p 5433" restart</userinput>
</screen></para>
  </refsect2>

  <refsect2 id="r2-app-pgctl-6">
   <title>Showing the Server Status</title>

   <para>
    Here is sample status output from
    <application>pg_ctl</application>:
<screen>
<prompt>$</prompt> <userinput>pg_ctl status</userinput>
<computeroutput>
pg_ctl: server is running (PID: 13718)
/usr/local/pgsql/bin/postgres "-D" "/usr/local/pgsql/data" "-p" "5433" "-B" "128"
</computeroutput></screen>
    The second line is the command that would be invoked in restart mode.
   </para>
  </refsect2>
 </refsect1>


 <refsect1>
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="app-initdb"/></member>
   <member><xref linkend="app-postgres"/></member>
  </simplelist>
 </refsect1>

</refentry>
