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<chapter id="backup">

<title>Backup and Restore</title>

you used as <replaceable class="parameter">outfile</replaceable>

for the pg_dump command. The database <replaceable

class="parameter">dbname</replaceable> will not be created by this

command, you mustdo that yourself before executing

<application>psql</> (e.g., with <userinput>createdb<replaceable

class="parameter">dbname</></userinput>). <application>psql</>

supports similar options to <application>pg_dump</>for

controlling the database server location and the user names. See

command, you mustcreate it yourself from template0 before executing

<application>psql</> (e.g., with <userinput>createdb-t template0

<replaceableclass="parameter">dbname</></userinput>).

<application>psql</>supports similar options to <application>pg_dump</>

forcontrolling the database server location and the user names. See

its reference page for more information.

</para>

</programlisting>

</informalexample>

</para>

<important>

<para>

The dumps produced by pg_dump are relative to template0. This means

that any languages, procedure etc added to template1 will also be

dumped by <application>pg_dump</>. As a result, when restoring, if

you are using a customized template1, you must create the empty

database from template0, as in the example above.

</para>

</important>

</sect2>

<sect2>

</para>

</formalpara>

<formalpara>

<title>Use the custom dump format (V7.1).</title>

<para>

If PostgreSQL was built on a system with the zlib compression library

installed, the custom dump format will compress data as it writes it

to the output file. For large databases, this will produce similar dump

sizes to using gzip, but has the added advantage that the tables can be

restored selectively. The following command dumps a database using the

custom dump format:

<informalexample>

<programlisting>

pg_dump -Fc <replaceable class="parameter">dbname</replaceable> > <replaceable class="parameter">filename</replaceable>

</programlisting>

</informalexample>

See the <application>pg_dump</> and <application>pg_restore</> reference pages for details.

</para>

</formalpara>

</sect2>

<sect2>

</para>

<para>

Large objects are not handled by <application>pg_dump</>. The

directory <filename>contrib/pg_dumplo</> of the

<productname>Postgres</> source tree contains a program that can

do that.

For reasons of backward compatibility, <application>pg_dump</> does

not dump large objects by default. To dump large objects you must use

either custom or TAR output format, and use the -B option in

<application>pg_dump</>. See the reference pages for details.

The directory <filename>contrib/pg_dumplo</> of the

<productname>Postgres</> source tree also contains a program that can

dump large objects.

</para>

<para>