pg_dump.sgml

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$Header: /cvsroot/pgsql/doc/src/sgml/ref/pg_dump.sgml,v 1.29 2001/03/06 05:22:18 pjw Exp $
Postgres documentation
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<refentry id="APP-PGDUMP">
 <docinfo>
  <date>2000-12-25</date>
 </docinfo>

 <refmeta>
  <refentrytitle id="app-pgdump-title">
   <application>pg_dump</application>
  </refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo>Application</refmiscinfo>
 </refmeta>
 <refnamediv>
  <refname>
   <application>pg_dump</application>
  </refname>
  <refpurpose>
   Extract a <productname>Postgres</productname> database into a script file or other archive file 
  </refpurpose>
 </refnamediv>
 <refsynopsisdiv>
  <refsynopsisdivinfo>
   <date>2000-11-22</date>
  </refsynopsisdivinfo>
  <synopsis>
pg_dump [ <replaceable class="parameter">dbname</replaceable> ]
pg_dump [ -h <replaceable class="parameter">host</replaceable> ]
    [ -p <replaceable class="parameter">port</replaceable> ]
    [ -t <replaceable class="parameter">table</replaceable> ]
    [ -a  ] [ -b ] [ -c  ] [-C] [ -d  ] [ -D  ] 
    [-f <REPLACEABLE CLASS="PARAMETER">file</REPLACEABLE>] 
    [-F <REPLACEABLE CLASS="PARAMETER">format</REPLACEABLE>] 
    [ -i  ] [ -n  ] [ -N  ] [ -o  ] [ -O ] [-R] 
    [ -s  ] [ -S ] [ -u  ] [ -v  ] [ -x ] [ -Z 0..9 ] 
    [ <replaceable class="parameter">dbname</replaceable> ]
  </synopsis>

  <refsect2 id="R2-APP-PG-DUMP-1">
   <refsect2info>
    <date>2000-11-22</date>
   </refsect2info>
   <title>
    Inputs
   </title>
   <para>
    <application>pg_dump</application> accepts the following command
    line arguments:

    <variablelist>
     <varlistentry>
      <term><replaceable class="parameter">dbname</replaceable></term>
      <listitem>
       <para>
	Specifies the name of the database to be extracted.
	<replaceable class="parameter">dbname</replaceable>
	defaults to the value of the
	<envar>USER</envar>
	environment variable.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-a</term>
      <listitem>
       <para>
	Dump out only the data, no schema (definitions).
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-b</term>
      <listitem>
       <para>
 	Dump data and BLOB data.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-c</term>
      <listitem>
       <para>
	Clean (drop) schema prior to create.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-C</term>
      <listitem>
       <para>
	For plain text (script) output, include SQL to create the database itself.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-d</term>
      <listitem>
       <para>
	Dump data as proper insert strings. This is not recommended for large databases
      for performance reasons.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-D</term>
      <listitem>
       <para>
	Dump data as inserts with attribute names. This is not recommended for large databases
      for performance reasons.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-f <replaceable class="parameter">file</replaceable></term>
      <listitem>
       <para>
	Send output to the specified file.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-F <replaceable class="parameter">format</replaceable></term>
      <listitem>
       <para>
	Format can be one of the following:
       </para>


       <variablelist>
        <varlistentry>
         <term>p</term>
         <listitem>
          <para>
         output a plain text SQL script file (default)
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term>t</term>
         <listitem>
          <para>
         output a TAR archive suitable for input into 
         <APPLICATION>pg_restore</APPLICATION>. Using this archive format 
         allows reordering and/or exclusion of schema elements 
         at the time the database is restored. It is also possible to limit 
         which data is reloaded at restore time.
          </para>
         </listitem>
        </varlistentry>

        <varlistentry>
         <term>c</term>
         <listitem>
          <para>
         output a custom archive suitable for input into 
         <APPLICATION>pg_restore</APPLICATION>. This is the most flexible 
         format in that it allows reordering of data load as well 
         as schema elements. This format is also compressed by default.
          </para>
         </listitem>
        </varlistentry>

       </variablelist>

      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-i</term>
      <listitem>
       <para>
        Ignore version mismatch between <application>pg_dump</application>
	and the database server.  Since <application>pg_dump</application>
	knows a great deal about system catalogs, any given version of
	<application>pg_dump</application> is only intended to work with
	the corresponding release of the database server.  Use this option
	if you need to override the version check (and if
	<application>pg_dump</application> then fails, don't
	say you weren't warned).
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-n</term>
      <listitem>
       <para>
	Suppress double quotes around identifiers unless absolutely necessary.
	This may cause trouble loading this dumped data if there are reserved words
	used for identifiers. 
	This was the default behavior for
	<application>pg_dump</application> prior to v6.4.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-N</term>
      <listitem>
       <para>
	Include double quotes around identifiers.
	This is the default.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-o</term>
      <listitem>
       <para>
	Dump object identifiers (<acronym>OID</acronym>s) for every table.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-O</term>
      <listitem>
       <para>
	In plain text output mode, don't set object ownership to match the 
      original database. Typically, <APPLICATION>pg_dump</APPLICATION> 
      issues <PROGRAMLISTING>\connect</PROGRAMLISTING> statments to set 
      ownership of schema elements.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-R</term>
      <listitem>
       <para>
	In plain text output mode, prohibit <APPLICATION>pg_dump</APPLICATION> 
      from issuing any <PROGRAMLISTING>\connect</PROGRAMLISTING> statements.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-s</term>
      <listitem>
       <para>
	Dump out only the schema (definitions), no data.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-S <replaceable class="parameter">username</replaceable></term>
      <listitem>
       <para>
	Specify the superuser username to use when disabling triggers and/or 
      setting ownership of schema elements.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-t <replaceable class="parameter">table</replaceable></term>
      <listitem>
       <para>
	Dump data for <replaceable class="parameter">table</replaceable> only.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-u</term>
      <listitem>
       <para>
	Use password authentication. Prompts for username and password.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-v</term>
      <listitem>
       <para>
	Specifies verbose mode.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-x</term>
      <listitem>
       <para>
	Prevent dumping of ACLs (grant/revoke commands) and table ownership information.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-Z <replaceable class="parameter">0..9</replaceable></term>
      <listitem>
       <para>
	Specify the compression level to use in archive formats that support 
      compression (currently only the custom archive format supports compression).
       </para>
      </listitem>
     </varlistentry>


    </variablelist>
   </para>
   <para>
    <application>pg_dump</application> also accepts 
    the following command line arguments for connection parameters:

    <variablelist>
     <varlistentry>
      <term>-h <replaceable class="parameter">host</replaceable></term>
      <listitem>
       <para>
	Specifies the hostname of the machine on which the 
	<application>postmaster</application>
	is running.  If host begins with a slash, it is used 
	as the directory for the unix domain socket.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-p <replaceable class="parameter">port</replaceable></term>
      <listitem>
       <para>
	Specifies the Internet TCP/IP port or local Unix domain socket file 
	extension on which the <application>postmaster</application>
	is listening for connections.  The port number defaults to 5432,
	or the value of the <envar>PGPORT</envar>
	environment variable (if set).
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term>-u</term>
      <listitem>
       <para>
	Use password authentication. 
	Prompts for
	<replaceable class="parameter">username</replaceable>
	and <replaceable class="parameter">password</replaceable>.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </para>
  </refsect2>

  <refsect2 id="R2-APP-PG-DUMP-2">
   <refsect2info>
    <date>1998-11-05</date>
   </refsect2info>
   <title>
    Outputs
   </title>
   <para>
    <application>pg_dump</application> will create a file or
    write to <filename>stdout</filename>.

    <variablelist>
     <varlistentry>
      <term><computeroutput>
Connection to database 'template1' failed.
connectDBStart() -- connect() failed: No such file or directory
        Is the postmaster running locally
        and accepting connections on Unix socket '/tmp/.s.PGSQL.5432'?
       </computeroutput></term>
      <listitem>
       <para>
	<application>pg_dump</application> could not attach to the 
	<application>postmaster</application> 
	process on the specified host and port.  If you see this message,
	ensure that the <application>postmaster</application> 
	is running on the proper host and that you have specified the proper
	port.  If your site uses an authentication system, ensure that you
	have obtained the required authentication credentials.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><computeroutput>
Connection to database '<replaceable class="parameter">dbname</replaceable>' failed.
FATAL 1:  SetUserId: user '<replaceable class="parameter">username</replaceable>' is not in 'pg_shadow'
       </computeroutput></term>
      <listitem>
       <para>
	You do not have a valid entry in the relation <literal>pg_shadow</literal>
	and and will not be allowed to access <productname>Postgres</productname>. 
	Contact your <productname>Postgres</productname> administrator.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><computeroutput>
dumpSequence(<replaceable class="parameter">table</replaceable>): SELECT failed
       </computeroutput></term>
      <listitem>
       <para>
	You do not have permission to read the database.
	Contact your <productname>Postgres</productname> site administrator.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </para>

   <note>
    <para>
     <application>pg_dump</application> internally executes
     <command>SELECT</command> statements. If you have problems running
     <application>pg_dump</application>,
     make sure you are able to select information from the database using, for
     example, <application>psql</application>.
    </para>
   </note>
  </refsect2>
 </refsynopsisdiv>

 <refsect1 id="R1-APP-PG-DUMP-1">
  <refsect1info>
   <date>2000-</date>
  </refsect1info>
  <title>
   Description
  </title>
  <para>
   <application>pg_dump</application> is a utility for dumping out a 
   <productname>Postgres</productname> database into a script or archive 
   file containing query commands. The script files are in text format 
   and can be used to reconstruct the database, even on other machines 
   and other architectures.
  </para>
  <para> 
   The archive files, new with version 7.1, contain enough information for 
   <APPLICATION>pg_restore</APPLICATION> to rebuild the database, but also
   allow pg_restore to be selective about what is restored, or even to 
   reorder the items prior to being restored. The archive files should 
   also be portable across architectures.
  </para>
  <para>
   <application>pg_dump</application> 
   will produce the queries necessary to re-generate all
   user-defined types, functions, tables, indices, aggregates, and
   operators.  In addition, all the data is copied out in text format so
   that it can be readily copied in again, as well as imported into tools
   for editing.
  </para>

  <para>
   <application>pg_dump</application> 
   is useful for dumping out the contents of a database to move from one
   <productname>Postgres</productname> installation to another.  After running 
   <application>pg_dump</application>,
   one should examine the output for any warnings, especially
   in light of the limitations listed below. 
  </para>

  <para>
   When used with one of the alternate file formats and combined with 
   <APPLICATION>pg_restore</APPLICATION>, it provides a flexible archival 
   and trasfer mechanism. <APPLICATION>pg_dump</APPLICATION> can be used 
   to backup an entire database, then <APPLICATION>pg_restore</APPLICATION> 
   can be used to examine the archive and/or select which parts of the 
   database are to be restored.
  </para>

  <para>
   See the <APPLICATION>pg_restore</APPLICATION> documentation for details.
  </para>

 </refsect1>

 <refsect1 id="R1-APP-PG-DUMP-2">
  <refsect1info>
   <date>2000-11-21</date>
  </refsect1info>
  <title>
   Notes
  </title>
  <para>
   <application>pg_dump</application> has a few limitations.
   The limitations mostly stem from
   difficulty in extracting certain meta-information from the system
   catalogs.

   <itemizedlist>
    <listitem>
     <para>
      <application>pg_dump</application> 
      does not understand partial indices. The reason is
      the same as above; partial index predicates are stored as plans.
     </para>
    </listitem>

    <listitem>
     <para>
      When dumping a single table or as plain text, <application>pg_dump</application> 
      does not handle large objects. Large objects must be dumped in their
      entirity using one of the binary archive formats.
     </para>
    </listitem>

    <listitem>
     <para>
      When doing a data only dump, <application>pg_dump</application> emits queries
      to disable triggers on user tables before inserting the data and queries to
      re-enable them after the data has been inserted.  If the restore is stopped
      in the middle, the system catalogs may be left in the wrong state.
     </para>
    </listitem>

   </itemizedlist>
  </para>
 </refsect1>

 <refsect1 id="R1-APP-PG-DUMP-3">
  <refsect1info>
   <date>2000-11-21</date>
  </refsect1info>
  <title>
   Usage
  </title>
  <para>
   To dump a database of the same name as the user:

   <programlisting>
$ pg_dump > db.out
   </programlisting>
  </para>

  <para>
   To reload this database:

   <programlisting>
$ psql -e database < db.out
   </programlisting>
  </para>

  <para>
   To dump a database called mydb that contains BLOBs to a TAR file:

   <programlisting>
$ pg_dump -Ft --blobs mydb > db.tar
   </programlisting>
  </para>

  <para>
   To reload this database (with BLOBs) to an existing db called newdb:

   <programlisting>
$ pg_restore db.tar --dbname=newdb
   </programlisting>
  </para>

 </refsect1>
</refentry>

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