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$PostgreSQL: pgsql/doc/src/sgml/ref/initdb.sgml,v 1.37.2.2 2007/03/26 17:23:44 tgl Exp $
PostgreSQL documentation
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<refentry id="APP-INITDB">
 <refmeta>
  <refentrytitle id="APP-INITDB-TITLE">initdb</refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo>Application</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>initdb</refname>
  <refpurpose>create a new <productname>PostgreSQL</productname> database cluster</refpurpose>
 </refnamediv>

 <indexterm zone="app-initdb">
  <primary>initdb</primary>
 </indexterm>

 <refsynopsisdiv>
  <cmdsynopsis>
   <command>initdb</command>
   <arg rep="repeat"><replaceable>option</></arg>
   <group choice="plain">
    <arg>--pgdata </arg>
    <arg>-D </arg>
    <replaceable>directory</replaceable>
   </group>
  </cmdsynopsis>
 </refsynopsisdiv>

 <refsect1 id="R1-APP-INITDB-1">
  <title>
   Description
  </title>
  <para>
   <command>initdb</command> creates a new
   <productname>PostgreSQL</productname> database cluster.  A database
   cluster is a collection of databases that are managed by a single
   server instance.
  </para>

  <para>
   Creating a database cluster consists of creating the directories in
   which the database data will live, generating the shared catalog
   tables (tables that belong to the whole cluster rather than to any
   particular database), and creating the <literal>template1</literal>
   and <literal>postgres</literal> databases. When you later create a 
   new database, everything in the <literal>template1</literal> database is 
   copied.  (Therefore, anything installed in <literal>template1</literal>
   is automatically copied into each database created later.)
   The <literal>postgres</literal> database is a default database meant
   for use by users, utilities and third party applications.
  </para>

  <para>
   Although <command>initdb</command> will attempt to create the
   specified data directory, it might not have permission if the parent
   directory of the desired data directory is root-owned. To initialize
   in such a setup, create an empty data directory as root, then use
   <command>chown</command> to assign ownership of that directory to the
   database user account, then <command>su</command> to become the
   database user to run <command>initdb</command>.
  </para>

  <para>
   <command>initdb</command> must be run as the user that will own the
   server process, because the server needs to have access to the
   files and directories that <command>initdb</command> creates.
   Since the server may not be run as root, you must not run
   <command>initdb</command> as root either.  (It will in fact refuse
   to do so.)
  </para>

  <para>
   <command>initdb</command> initializes the database cluster's default
   locale and character set encoding. The collation order
   (<literal>LC_COLLATE</>) and character set classes
   (<literal>LC_CTYPE</>, e.g. upper, lower, digit) are fixed for all
   databases and can not be changed. Collation orders other than
   <literal>C</> or <literal>POSIX</> also have a performance penalty.
   For these reasons it is important to choose the right locale when
   running <command>initdb</command>. The remaining locale categories
   can be changed later when the server is started. All server locale
   values (<literal>lc_*</>) can be displayed via <command>SHOW ALL</>.
   More details can be found in <xref linkend="locale">.
  </para>

  <para>
   The character set encoding can be set separately for a database when
   it is created. <command>initdb</command> determines the encoding for
   the <literal>template1</literal> database, which will serve as the
   default for all other databases. To alter the default encoding use
   the <option>--encoding</option> option. More details can be found in
   <xref linkend="multibyte">.
  </para>

 </refsect1>

 <refsect1>
  <title>Options</title>

   <para>
    <variablelist>
     <varlistentry>
      <term><option>-A <replaceable class="parameter">authmethod</replaceable></option></term>
      <term><option>--auth=<replaceable class="parameter">authmethod</replaceable></option></term>
      <listitem>
       <para>
        This option specifies the authentication method for local users
        used in <filename>pg_hba.conf</>.  Do not use <literal>trust</>
        unless you trust all local users on your system.  <literal>Trust</> 
        is the default for ease of installation.
       </para>
      </listitem>
     </varlistentry>

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

     <varlistentry>
      <term><option>-E <replaceable class="parameter">encoding</replaceable></option></term>
      <term><option>--encoding=<replaceable class="parameter">encoding</replaceable></option></term>
      <listitem>
       <para>
        Selects the encoding of the template database. This will also
        be the default encoding of any database you create later,
        unless you override it there.  The default is derived from the locale, or
        <literal>SQL_ASCII</literal> if that does not work. The character sets supported by
        the <productname>PostgreSQL</productname> server are described
        in <xref linkend="multibyte-charset-supported">.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>--locale=<replaceable>locale</replaceable></option></term>
      <listitem>
       <para>
        Sets the default locale for the database cluster.  If this
        option is not specified, the locale is inherited from the
        environment that <command>initdb</command> runs in. Locale
        support is described in <xref linkend="locale">.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>--lc-collate=<replaceable>locale</replaceable></option></term>
      <term><option>--lc-ctype=<replaceable>locale</replaceable></option></term>
      <term><option>--lc-messages=<replaceable>locale</replaceable></option></term>
      <term><option>--lc-monetary=<replaceable>locale</replaceable></option></term>
      <term><option>--lc-numeric=<replaceable>locale</replaceable></option></term>
      <term><option>--lc-time=<replaceable>locale</replaceable></option></term>

      <listitem>
       <para>
        Like <option>--locale</option>, but only sets the locale in
        the specified category.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-U <replaceable class="parameter">username</replaceable></option></term>
      <term><option>--username=<replaceable class="parameter">username</replaceable></option></term>
      <listitem>
       <para>
        Selects the user name of the database superuser. This defaults
        to the name of the effective user running
        <command>initdb</command>. It is really not important what the
        superuser's name is, but one might choose to keep the
        customary name <systemitem>postgres</systemitem>, even if the operating
        system user's name is different.
       </para>
      </listitem>
     </varlistentry>
 
     <varlistentry>
      <term><option>-W</option></term>
      <term><option>--pwprompt</option></term>
      <listitem>
       <para>
        Makes <command>initdb</command> prompt for a password
        to give 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><option>--pwfile=<replaceable>filename</></option></term>
      <listitem>
       <para>
        Makes <command>initdb</command> read the database superuser's password
        from a file.  The first line of the file is taken as the password.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </para>

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

    <variablelist>
     <varlistentry>
      <term><option>-d</option></term>
      <term><option>--debug</option></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 <command>initdb</command>
	uses to create the catalog tables.  This option generates a tremendous
	amount of extremely boring output.
       </para>
      </listitem>
     </varlistentry>

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

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

 </refsect1>

 <refsect1>
  <title>Environment</title>

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

    <listitem>
     <para>
      Specifies the directory where the database cluster is to be
      stored; may be overridden using the <option>-D</option> option.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>

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

 </refsect1>

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

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

</refentry>