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Postgres documentation
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<refentry id="APP-INITDB">
 <docinfo>
  <date>2000-11-11</date>
 </docinfo>

 <refmeta>
  <refentrytitle id="APP-INITDB-TITLE"><application>initdb</application></refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo>Application</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>initdb</refname>
  <refpurpose>Create a new <productname>Postgres</productname> database cluster</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
  <cmdsynopsis>
   <command>initdb</command>
    <group choice="plain">
     <arg>--pgdata </arg>
     <arg>-D </arg>
     <replaceable>dbdir</replaceable>
    </group>
    <group>
     <arg>--sysid </arg>
     <arg>-i </arg>
     <replaceable>sysid</replaceable>
    </group>
    <group><arg>--pwprompt</arg><arg>-W</arg></group>
    <group>
     <arg>--encoding </arg>
     <arg>-E </arg>
     <replaceable>encoding</replaceable>
    </group>
    <arg>-L <replaceable>directory</replaceable></arg>
    <group><arg>--noclean</arg><arg>-n</arg></group>
    <group><arg>--debug</arg><arg>-d</arg></group>
    <group><arg>--template</arg><arg>-t</arg></group>
  </cmdsynopsis>
 </refsynopsisdiv>

 <refsect1 id="R1-APP-INITDB-1">
  <title>
   Description
  </title>
  <para>
   <application>initdb</application> creates a new
   <productname>Postgres</productname> database cluster or system.  A
   database cluster is a collection of databases that are managed by a
   single postmaster.
  </para>
  <para>
   Creating a database system consists of creating the directories in which
   the database data will live, generating the shared catalog tables 
   (tables that don't belong to any particular database), and
   creating the <literal>template1</literal>
   database.  When you create a new database, everything in the
   <literal>template1</literal> database is copied.
   It contains catalog tables filled in for things like the
   built-in types.
  </para>

  <para>
   You must not execute <application>initdb</application> as root. This is
   because you cannot run the database server as root either, but the
   server needs to have access to the files <application>initdb</application>
   creates. Furthermore, during the initialization phase, when there are no
   users and no access controls installed, <productname>Postgres</productname>
   will only connect with
   the name of the current Unix user, so you must log in under the account
   that will own the server process.
  </para>

  <para>
   Although <application>initdb</application> will attempt to create the respective
   data directory, chances are that it won't have the permission to do so. Thus
   it is a good idea to create the data directory before running <application>initdb</application>
   <emphasis>and</emphasis> to hand over the ownership of it to the database superuser.
  </para>

  <refsect2>
   <title>Options</title>

   <para>
    <variablelist>
     <varlistentry>
      <term>--pgdata=<replaceable class="parameter">dbdir</replaceable></term>
      <term>-D <replaceable class="parameter">dbdir</replaceable></term>
      <listitem>
       <para>
        This option specifies where in the file system the database should be
        stored. This is the only information required by initdb, but you can avoid
        it by setting the <envar>PGDATA</envar> environment variable, which
        can be convenient since the database server (<filename>postmaster</filename>)
        can find the database directory later by the same variable.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>--sysid=<replaceable class="parameter">sysid</replaceable></term>
      <term>-i <replaceable class="parameter">sysid</replaceable></term>
      <listitem>
       <para>
        Selects the system id of the database superuser. This defaults to
        the effective user id of the user running initdb. It is really
        not important what the superuser's sysid is, but one might choose
        to start the numbering at some number like 1.
       </para>
      </listitem>
     </varlistentry>
 
     <varlistentry>
      <term>--pwprompt</term>
      <term>-W</term>
      <listitem>
       <para>
        Makes initdb prompt for a password of the database superuser. If you
        don't plan on using password authentication, this is not important.
        Otherwise you won't be able to use password authentication until
        you have a password set up.
       </para>
      </listitem>
     </varlistentry>
 
     <varlistentry>
      <term>--encoding=<replaceable class="parameter">encoding</replaceable></term>
      <term>-E <replaceable class="parameter">encoding</replaceable></term>
      <listitem>
       <para>
        Selects the multibyte encoding of the template database. This will also
        be the default encoding of any database you create later, unless you
        override it there. To use the multibyte encoding feature, you must
        specify so at build time, at which time you also select the default
        for this option.
       </para>
      </listitem>
     </varlistentry>

   </variablelist>
   </para>

   <para>
    Other, less commonly used, parameters are also available:

    <variablelist>
     <varlistentry>
      <term>-L <replaceable class="parameter">directory</replaceable></term>
      <listitem>
       <para>
        Specifies where initdb should find its input files to
        initialize the database system.  This is normally not
        necessary.  You will be told if you need to specify their
        location explicitly.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>--template</term>
      <term>-t</term>
      <listitem>
       <para>
	Replace the <literal>template1</literal>
	database in an existing database system, and don't touch anything else.
	This is useful when you need to upgrade your <literal>template1</literal>
	database using <application>initdb</application>
	from a newer release of <productname>Postgres</productname>, 
	or when your <literal>template1</literal>
	database has become corrupted by some system problem.  Normally the
	contents of <literal>template1</literal>
	remain constant throughout the life of the database system.  You can't
	destroy anything by running <application>initdb</application>
	with the 
	<option>--template</option>
	option.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>--noclean</term>
      <term>-n</term>
      <listitem>
       <para>
	By default, when <application>initdb</application>
	determines that an error prevented it from completely creating the database
	system, it removes any files it may have created before determining
	that it can't finish the job. This option inhibits any tidying-up and is
	thus useful for debugging.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>--debug</term>
      <term>-d</term>
      <listitem>
       <para>
	Print debugging output from the bootstrap backend and a few other
        messages of lesser interest for the general public.
	The bootstrap backend is the program <application>initdb</application>
	uses to create the catalog tables.  This option generates a tremendous
	amount of output.
       </para>
      </listitem>
     </varlistentry>

    </variablelist>
   </para>

  </refsect2>
 </refsect1>

 <refsect1>
  <title>See also</title>

  <simpara>
   <citetitle>PostgreSQL Administrator's Guide</citetitle>
  </simpara>
 </refsect1>

</refentry>

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