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<!--
doc/src/sgml/ref/pg_dump.sgml
PostgreSQL documentation
-->
<refentry id="app-pgdump">
<indexterm zone="app-pgdump">
<primary>pg_dump</primary>
</indexterm>
<refmeta>
<refentrytitle><application>pg_dump</application></refentrytitle>
<manvolnum>1</manvolnum>
<refmiscinfo>Application</refmiscinfo>
</refmeta>
<refnamediv>
<refname>pg_dump</refname>
<refpurpose>
extract a <productname>PostgreSQL</productname> database into a script file or other archive file
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>pg_dump</command>
<arg rep="repeat"><replaceable>connection-option</replaceable></arg>
<arg rep="repeat"><replaceable>option</replaceable></arg>
<arg choice="opt"><replaceable>dbname</replaceable></arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1 id="pg-dump-description">
<title>Description</title>
<para>
<application>pg_dump</application> is a utility for backing up a
<productname>PostgreSQL</productname> database. It makes consistent
backups even if the database is being used concurrently.
<application>pg_dump</application> does not block other users
accessing the database (readers or writers).
</para>
<para>
<application>pg_dump</application> only dumps a single database.
To back up an entire cluster, or to back up global objects that are
common to all databases in a cluster (such as roles and tablespaces),
use <xref linkend="app-pg-dumpall"/>.
</para>
<para>
Dumps can be output in script or archive file formats. Script
dumps are plain-text files containing the SQL commands required
to reconstruct the database to the state it was in at the time it was
saved. To restore from such a script, feed it to <xref
linkend="app-psql"/>. Script files
can be used to reconstruct the database even on other machines and
other architectures; with some modifications, even on other SQL
database products.
</para>
<para>
The alternative archive file formats must be used with
<xref linkend="app-pgrestore"/> to rebuild the database. They
allow <application>pg_restore</application> to be selective about
what is restored, or even to reorder the items prior to being
restored.
The archive file formats are designed to be portable across
architectures.
</para>
<para>
When used with one of the archive file formats and combined with
<application>pg_restore</application>,
<application>pg_dump</application> provides a flexible archival and
transfer 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. The most flexible output file formats are
the <quote>custom</quote> format (<option>-Fc</option>) and the
<quote>directory</quote> format (<option>-Fd</option>). They allow
for selection and reordering of all archived items, support parallel
restoration, and are compressed by default. The <quote>directory</quote>
format is the only format that supports parallel dumps.
</para>
<para>
While running <application>pg_dump</application>, one should examine the
output for any warnings (printed on standard error), especially in
light of the limitations listed below.
</para>
</refsect1>
<refsect1 id="pg-dump-options">
<title>Options</title>
<para>
The following command-line options control the content and
format of the output.
<variablelist>
<varlistentry>
<term><replaceable class="parameter">dbname</replaceable></term>
<listitem>
<para>
Specifies the name of the database to be dumped. If this is
not specified, the environment variable
<envar>PGDATABASE</envar> is used. If that is not set, the
user name specified for the connection is used.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-a</option></term>
<term><option>--data-only</option></term>
<listitem>
<para>
Dump only the data, not the schema (data definitions).
Table data, large objects, and sequence values are dumped.
</para>
<para>
This option is similar to, but for historical reasons not identical
to, specifying <option>--section=data</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-b</option></term>
<term><option>--blobs</option></term>
<listitem>
<para>
Include large objects in the dump. This is the default behavior
except when <option>--schema</option>, <option>--table</option>, or
<option>--schema-only</option> is specified. The <option>-b</option>
switch is therefore only useful to add large objects to dumps
where a specific schema or table has been requested. Note that
blobs are considered data and therefore will be included when
<option>--data-only</option> is used, but not
when <option>--schema-only</option> is.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-B</option></term>
<term><option>--no-blobs</option></term>
<listitem>
<para>
Exclude large objects in the dump.
</para>
<para>
When both <option>-b</option> and <option>-B</option> are given, the behavior
is to output large objects, when data is being dumped, see the
<option>-b</option> documentation.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-c</option></term>
<term><option>--clean</option></term>
<listitem>
<para>
Output commands to clean (drop)
database objects prior to outputting the commands for creating them.
(Unless <option>--if-exists</option> is also specified,
restore might generate some harmless error messages, if any objects
were not present in the destination database.)
</para>
<para>
This option is ignored when emitting an archive (non-text) output
file. For the archive formats, you can specify the option when you
call <command>pg_restore</command>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-C</option></term>
<term><option>--create</option></term>
<listitem>
<para>
Begin the output with a command to create the
database itself and reconnect to the created database. (With a
script of this form, it doesn't matter which database in the
destination installation you connect to before running the script.)
If <option>--clean</option> is also specified, the script drops and
recreates the target database before reconnecting to it.
</para>
<para>
With <option>--create</option>, the output also includes the
database's comment if any, and any configuration variable settings
that are specific to this database, that is,
any <command>ALTER DATABASE ... SET ...</command>
and <command>ALTER ROLE ... IN DATABASE ... SET ...</command>
commands that mention this database.
Access privileges for the database itself are also dumped,
unless <option>--no-acl</option> is specified.
</para>
<para>
This option is ignored when emitting an archive (non-text) output
file. For the archive formats, you can specify the option when you
call <command>pg_restore</command>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-e <replaceable class="parameter">pattern</replaceable></option></term>
<term><option>--extension=<replaceable class="parameter">pattern</replaceable></option></term>
<listitem>
<para>
Dump only extensions matching <replaceable
class="parameter">pattern</replaceable>. When this option is not
specified, all non-system extensions in the target database will be
dumped. Multiple extensions can be selected by writing multiple
<option>-e</option> switches. The <replaceable
class="parameter">pattern</replaceable> parameter is interpreted as a
pattern according to the same rules used by
<application>psql</application>'s <literal>\d</literal> commands (see
<xref linkend="app-psql-patterns"/>), so multiple extensions can also
be selected by writing wildcard characters in the pattern. When using
wildcards, be careful to quote the pattern if needed to prevent the
shell from expanding the wildcards.
</para>
<para>
Any configuration relation registered by
<function>pg_extension_config_dump</function> is included in the
dump if its extension is specified by <option>--extension</option>.
</para>
<note>
<para>
When <option>-e</option> is specified,
<application>pg_dump</application> makes no attempt to dump any other
database objects that the selected extension(s) might depend upon.
Therefore, there is no guarantee that the results of a
specific-extension dump can be successfully restored by themselves
into a clean database.
</para>
</note>
</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>
Create the dump in the specified character set encoding. By default,
the dump is created in the database encoding. (Another way to get the
same result is to set the <envar>PGCLIENTENCODING</envar> environment
variable to the desired dump encoding.) The supported encodings are
described in <xref linkend="multibyte-charset-supported"/>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-f <replaceable class="parameter">file</replaceable></option></term>
<term><option>--file=<replaceable class="parameter">file</replaceable></option></term>
<listitem>
<para>
Send output to the specified file. This parameter can be omitted for
file based output formats, in which case the standard output is used.
It must be given for the directory output format however, where it
specifies the target directory instead of a file. In this case the
directory is created by <command>pg_dump</command> and must not exist
before.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-F <replaceable class="parameter">format</replaceable></option></term>
<term><option>--format=<replaceable class="parameter">format</replaceable></option></term>
<listitem>
<para>
Selects the format of the output.
<replaceable>format</replaceable> can be one of the following:
<variablelist>
<varlistentry>
<term><literal>p</literal></term>
<term><literal>plain</literal></term>
<listitem>
<para>
Output a plain-text <acronym>SQL</acronym> script file (the default).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>c</literal></term>
<term><literal>custom</literal></term>
<listitem>
<para>
Output a custom-format archive suitable for input into
<application>pg_restore</application>.
Together with the directory output format, this is the most flexible
output format in that it allows manual selection and reordering of
archived items during restore. This format is also compressed by
default.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>d</literal></term>
<term><literal>directory</literal></term>
<listitem>
<para>
Output a directory-format archive suitable for input into
<application>pg_restore</application>. This will create a directory
with one file for each table and blob being dumped, plus a
so-called Table of Contents file describing the dumped objects in a
machine-readable format that <application>pg_restore</application>
can read. A directory format archive can be manipulated with
standard Unix tools; for example, files in an uncompressed archive
can be compressed with the <application>gzip</application> tool.
This format is compressed by default and also supports parallel
dumps.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>t</literal></term>
<term><literal>tar</literal></term>
<listitem>
<para>
Output a <command>tar</command>-format archive suitable for input
into <application>pg_restore</application>. The tar format is
compatible with the directory format: extracting a tar-format
archive produces a valid directory-format archive.
However, the tar format does not support compression. Also, when
using tar format the relative order of table data items cannot be
changed during restore.
</para>
</listitem>
</varlistentry>
</variablelist></para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-j <replaceable class="parameter">njobs</replaceable></option></term>
<term><option>--jobs=<replaceable class="parameter">njobs</replaceable></option></term>
<listitem>
<para>
Run the dump in parallel by dumping <replaceable class="parameter">njobs</replaceable>
tables simultaneously. This option may reduce the time needed to perform the dump but it also
increases the load on the database server. You can only use this option with the
directory output format because this is the only output format where multiple processes
can write their data at the same time.
</para>
<para><application>pg_dump</application> will open <replaceable class="parameter">njobs</replaceable>
+ 1 connections to the database, so make sure your <xref linkend="guc-max-connections"/>
setting is high enough to accommodate all connections.
</para>
<para>
Requesting exclusive locks on database objects while running a parallel dump could
cause the dump to fail. The reason is that the <application>pg_dump</application> coordinator process
requests shared locks on the objects that the worker processes are going to dump later
in order to
make sure that nobody deletes them and makes them go away while the dump is running.
If another client then requests an exclusive lock on a table, that lock will not be
granted but will be queued waiting for the shared lock of the coordinator process to be
released. Consequently any other access to the table will not be granted either and
will queue after the exclusive lock request. This includes the worker process trying
to dump the table. Without any precautions this would be a classic deadlock situation.
To detect this conflict, the <application>pg_dump</application> worker process requests another
shared lock using the <literal>NOWAIT</literal> option. If the worker process is not granted
this shared lock, somebody else must have requested an exclusive lock in the meantime
and there is no way to continue with the dump, so <application>pg_dump</application> has no choice
but to abort the dump.
</para>
<para>
For a consistent backup, the database server needs to support
synchronized snapshots, a feature that was introduced in
<productname>PostgreSQL</productname> 9.2 for primary servers and 10
for standbys. With this feature, database clients can ensure they see
the same data set even though they use different connections.
<command>pg_dump -j</command> uses multiple database connections; it
connects to the database once with the coordinator process and once again
for each worker job. Without the synchronized snapshot feature, the
different worker jobs wouldn't be guaranteed to see the same data in
each connection, which could lead to an inconsistent backup.
</para>
<para>
If you want to run a parallel dump of a pre-9.2 server, you need to make sure that the
database content doesn't change from between the time the coordinator connects to the
database until the last worker job has connected to the database. The easiest way to
do this is to halt any data modifying processes (DDL and DML) accessing the database
before starting the backup. You also need to specify the
<option>--no-synchronized-snapshots</option> parameter when running
<command>pg_dump -j</command> against a pre-9.2 <productname>PostgreSQL</productname>
server.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-n <replaceable class="parameter">pattern</replaceable></option></term>
<term><option>--schema=<replaceable class="parameter">pattern</replaceable></option></term>
<listitem>
<para>
Dump only schemas matching <replaceable
class="parameter">pattern</replaceable>; this selects both the
schema itself, and all its contained objects. When this option is
not specified, all non-system schemas in the target database will be
dumped. Multiple schemas can be
selected by writing multiple <option>-n</option> switches. The
<replaceable class="parameter">pattern</replaceable> parameter is
interpreted as a pattern according to the same rules used by
<application>psql</application>'s <literal>\d</literal> commands
(see <xref linkend="app-psql-patterns"/> below),
so multiple schemas can also be selected by writing wildcard characters
in the pattern. When using wildcards, be careful to quote the pattern
if needed to prevent the shell from expanding the wildcards; see
<xref linkend="pg-dump-examples"/> below.
</para>
<note>
<para>
When <option>-n</option> is specified, <application>pg_dump</application>
makes no attempt to dump any other database objects that the selected
schema(s) might depend upon. Therefore, there is no guarantee
that the results of a specific-schema dump can be successfully
restored by themselves into a clean database.
</para>
</note>
<note>
<para>
Non-schema objects such as blobs are not dumped when <option>-n</option> is
specified. You can add blobs back to the dump with the
<option>--blobs</option> switch.
</para>
</note>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-N <replaceable class="parameter">pattern</replaceable></option></term>
<term><option>--exclude-schema=<replaceable class="parameter">pattern</replaceable></option></term>
<listitem>
<para>
Do not dump any schemas matching <replaceable
class="parameter">pattern</replaceable>. The pattern is
interpreted according to the same rules as for <option>-n</option>.
<option>-N</option> can be given more than once to exclude schemas
matching any of several patterns.
</para>
<para>
When both <option>-n</option> and <option>-N</option> are given, the behavior
is to dump just the schemas that match at least one <option>-n</option>
switch but no <option>-N</option> switches. If <option>-N</option> appears
without <option>-n</option>, then schemas matching <option>-N</option> are
excluded from what is otherwise a normal dump.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-O</option></term>
<term><option>--no-owner</option></term>
<listitem>
<para>
Do not output commands to set
ownership of objects to match the original database.
By default, <application>pg_dump</application> issues
<command>ALTER OWNER</command> or
<command>SET SESSION AUTHORIZATION</command>
statements to set ownership of created database objects.
These statements
will fail when the script is run unless it is started by a superuser
(or the same user that owns all of the objects in the script).
To make a script that can be restored by any user, but will give
that user ownership of all the objects, specify <option>-O</option>.
</para>
<para>
This option is ignored when emitting an archive (non-text) output
file. For the archive formats, you can specify the option when you
call <command>pg_restore</command>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-R</option></term>
<term><option>--no-reconnect</option></term>
<listitem>
<para>
This option is obsolete but still accepted for backwards
compatibility.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-s</option></term>
<term><option>--schema-only</option></term>
<listitem>
<para>
Dump only the object definitions (schema), not data.
</para>
<para>
This option is the inverse of <option>--data-only</option>.
It is similar to, but for historical reasons not identical to,
specifying
<option>--section=pre-data --section=post-data</option>.
</para>
<para>
(Do not confuse this with the <option>--schema</option> option, which
uses the word <quote>schema</quote> in a different meaning.)
</para>
<para>
To exclude table data for only a subset of tables in the database,
see <option>--exclude-table-data</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-S <replaceable class="parameter">username</replaceable></option></term>
<term><option>--superuser=<replaceable class="parameter">username</replaceable></option></term>
<listitem>
<para>
Specify the superuser user name to use when disabling triggers.
This is relevant only if <option>--disable-triggers</option> is used.
(Usually, it's better to leave this out, and instead start the
resulting script as superuser.)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-t <replaceable class="parameter">pattern</replaceable></option></term>
<term><option>--table=<replaceable class="parameter">pattern</replaceable></option></term>
<listitem>
<para>
Dump only tables with names matching
<replaceable class="parameter">pattern</replaceable>. Multiple tables
can be selected by writing multiple <option>-t</option> switches. The
<replaceable class="parameter">pattern</replaceable> parameter is
interpreted as a pattern according to the same rules used by
<application>psql</application>'s <literal>\d</literal> commands
(see <xref linkend="app-psql-patterns"/> below),
so multiple tables can also be selected by writing wildcard characters
in the pattern. When using wildcards, be careful to quote the pattern
if needed to prevent the shell from expanding the wildcards; see
<xref linkend="pg-dump-examples"/> below.
</para>
<para>
As well as tables, this option can be used to dump the definition of matching
views, materialized views, foreign tables, and sequences. It will not dump the
contents of views or materialized views, and the contents of foreign tables will
only be dumped if the corresponding foreign server is specified with
<option>--include-foreign-data</option>.
</para>
<para>
The <option>-n</option> and <option>-N</option> switches have no effect when
<option>-t</option> is used, because tables selected by <option>-t</option> will
be dumped regardless of those switches, and non-table objects will not
be dumped.
</para>
<note>
<para>
When <option>-t</option> is specified, <application>pg_dump</application>
makes no attempt to dump any other database objects that the selected
table(s) might depend upon. Therefore, there is no guarantee
that the results of a specific-table dump can be successfully
restored by themselves into a clean database.
</para>
</note>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-T <replaceable class="parameter">pattern</replaceable></option></term>
<term><option>--exclude-table=<replaceable class="parameter">pattern</replaceable></option></term>
<listitem>
<para>
Do not dump any tables matching <replaceable
class="parameter">pattern</replaceable>. The pattern is
interpreted according to the same rules as for <option>-t</option>.
<option>-T</option> can be given more than once to exclude tables
matching any of several patterns.
</para>
<para>
When both <option>-t</option> and <option>-T</option> are given, the behavior
is to dump just the tables that match at least one <option>-t</option>
switch but no <option>-T</option> switches. If <option>-T</option> appears
without <option>-t</option>, then tables matching <option>-T</option> are
excluded from what is otherwise a normal dump.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-v</option></term>
<term><option>--verbose</option></term>
<listitem>
<para>
Specifies verbose mode. This will cause
<application>pg_dump</application> to output detailed object
comments and start/stop times to the dump file, and progress
messages to standard error.
Repeating the option causes additional debug-level messages
to appear on standard error.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-V</option></term>
<term><option>--version</option></term>
<listitem>
<para>
Print the <application>pg_dump</application> version and exit.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-x</option></term>
<term><option>--no-privileges</option></term>
<term><option>--no-acl</option></term>
<listitem>
<para>
Prevent dumping of access privileges (grant/revoke commands).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-Z <replaceable class="parameter">0..9</replaceable></option></term>
<term><option>--compress=<replaceable class="parameter">0..9</replaceable></option></term>
<listitem>
<para>
Specify the compression level to use. Zero means no compression.
For the custom and directory archive formats, this specifies compression of
individual table-data segments, and the default is to compress
at a moderate level.
For plain text output, setting a nonzero compression level causes
the entire output file to be compressed, as though it had been
fed through <application>gzip</application>; but the default is not to compress.
The tar archive format currently does not support compression at all.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--binary-upgrade</option></term>
<listitem>
<para>
This option is for use by in-place upgrade utilities. Its use
for other purposes is not recommended or supported. The
behavior of the option may change in future releases without
notice.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--column-inserts</option></term>
<term><option>--attribute-inserts</option></term>
<listitem>
<para>
Dump data as <command>INSERT</command> commands with explicit
column names (<literal>INSERT INTO
<replaceable>table</replaceable>
(<replaceable>column</replaceable>, ...) VALUES
...</literal>). This will make restoration very slow; it is mainly
useful for making dumps that can be loaded into
non-<productname>PostgreSQL</productname> databases.
Any error during reloading will cause only rows that are part of the
problematic <command>INSERT</command> to be lost, rather than the
entire table contents.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--disable-dollar-quoting</option></term>
<listitem>
<para>
This option disables the use of dollar quoting for function bodies,
and forces them to be quoted using SQL standard string syntax.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--disable-triggers</option></term>
<listitem>
<para>
This option is relevant only when creating a data-only dump.
It instructs <application>pg_dump</application> to include commands
to temporarily disable triggers on the target tables while
the data is reloaded. Use this if you have referential
integrity checks or other triggers on the tables that you
do not want to invoke during data reload.
</para>
<para>
Presently, the commands emitted for <option>--disable-triggers</option>
must be done as superuser. So, you should also specify
a superuser name with <option>-S</option>, or preferably be careful to
start the resulting script as a superuser.
</para>
<para>
This option is ignored when emitting an archive (non-text) output
file. For the archive formats, you can specify the option when you
call <command>pg_restore</command>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--enable-row-security</option></term>
<listitem>
<para>
This option is relevant only when dumping the contents of a table
which has row security. By default, <application>pg_dump</application> will set
<xref linkend="guc-row-security"/> to off, to ensure
that all data is dumped from the table. If the user does not have
sufficient privileges to bypass row security, then an error is thrown.
This parameter instructs <application>pg_dump</application> to set
<xref linkend="guc-row-security"/> to on instead, allowing the user
to dump the parts of the contents of the table that they have access to.
</para>
<para>
Note that if you use this option currently, you probably also want
the dump be in <command>INSERT</command> format, as the
<command>COPY FROM</command> during restore does not support row security.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--exclude-table-data=<replaceable class="parameter">pattern</replaceable></option></term>
<listitem>
<para>
Do not dump data for any tables matching <replaceable
class="parameter">pattern</replaceable>. The pattern is
interpreted according to the same rules as for <option>-t</option>.
<option>--exclude-table-data</option> can be given more than once to
exclude tables matching any of several patterns. This option is
useful when you need the definition of a particular table even
though you do not need the data in it.
</para>
<para>
To exclude data for all tables in the database, see <option>--schema-only</option>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--extra-float-digits=<replaceable class="parameter">ndigits</replaceable></option></term>
<listitem>
<para>
Use the specified value of <option>extra_float_digits</option> when dumping
floating-point data, instead of the maximum available precision.
Routine dumps made for backup purposes should not use this option.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--if-exists</option></term>
<listitem>
<para>
Use conditional commands (i.e., add an <literal>IF EXISTS</literal>
clause) when cleaning database objects. This option is not valid
unless <option>--clean</option> is also specified.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--include-foreign-data=<replaceable class="parameter">foreignserver</replaceable></option></term>
<listitem>
<para>
Dump the data for any foreign table with a foreign server
matching <replaceable class="parameter">foreignserver</replaceable>
pattern. Multiple foreign servers can be selected by writing multiple
<option>--include-foreign-data</option> switches.
Also, the <replaceable class="parameter">foreignserver</replaceable> parameter is
interpreted as a pattern according to the same rules used by
<application>psql</application>'s <literal>\d</literal> commands
(see <xref linkend="app-psql-patterns"/> below),
so multiple foreign servers can also be selected by writing wildcard characters
in the pattern. When using wildcards, be careful to quote the pattern
if needed to prevent the shell from expanding the wildcards; see
<xref linkend="pg-dump-examples"/> below.
The only exception is that an empty pattern is disallowed.
</para>
<note>
<para>
When <option>--include-foreign-data</option> is specified,
<application>pg_dump</application> does not check that the foreign
table is writable. Therefore, there is no guarantee that the
results of a foreign table dump can be successfully restored.
</para>
</note>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--inserts</option></term>
<listitem>
<para>
Dump data as <command>INSERT</command> commands (rather
than <command>COPY</command>). This will make restoration very slow;
it is mainly useful for making dumps that can be loaded into
non-<productname>PostgreSQL</productname> databases.
Any error during reloading will cause only rows that are part of the
problematic <command>INSERT</command> to be lost, rather than the
entire table contents. Note that the restore might fail altogether if
you have rearranged column order. The
<option>--column-inserts</option> option is safe against column order
changes, though even slower.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--load-via-partition-root</option></term>
<listitem>
<para>
When dumping data for a table partition, make
the <command>COPY</command> or <command>INSERT</command> statements
target the root of the partitioning hierarchy that contains it, rather
than the partition itself. This causes the appropriate partition to
be re-determined for each row when the data is loaded. This may be
useful when reloading data on a server where rows do not always fall
into the same partitions as they did on the original server. That
could happen, for example, if the partitioning column is of type text
and the two systems have different definitions of the collation used
to sort the partitioning column.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--lock-wait-timeout=<replaceable class="parameter">timeout</replaceable></option></term>
<listitem>
<para>
Do not wait forever to acquire shared table locks at the beginning of
the dump. Instead fail if unable to lock a table within the specified
<replaceable class="parameter">timeout</replaceable>. The timeout may be
specified in any of the formats accepted by <command>SET
statement_timeout</command>. (Allowed formats vary depending on the server
version you are dumping from, but an integer number of milliseconds
is accepted by all versions.)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-comments</option></term>
<listitem>
<para>
Do not dump comments.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-publications</option></term>
<listitem>
<para>
Do not dump publications.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-security-labels</option></term>
<listitem>
<para>
Do not dump security labels.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-subscriptions</option></term>
<listitem>
<para>
Do not dump subscriptions.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-sync</option></term>
<listitem>
<para>
By default, <command>pg_dump</command> will wait for all files
to be written safely to disk. This option causes
<command>pg_dump</command> to return without waiting, which is
faster, but means that a subsequent operating system crash can leave
the dump corrupt. Generally, this option is useful for testing
but should not be used when dumping data from production installation.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-synchronized-snapshots</option></term>
<listitem>
<para>
This option allows running <command>pg_dump -j</command> against a pre-9.2
server, see the documentation of the <option>-j</option> parameter
for more details.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-tablespaces</option></term>
<listitem>
<para>
Do not output commands to select tablespaces.
With this option, all objects will be created in whichever
tablespace is the default during restore.
</para>
<para>
This option is ignored when emitting an archive (non-text) output
file. For the archive formats, you can specify the option when you
call <command>pg_restore</command>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-toast-compression</option></term>
<listitem>
<para>
Do not output commands to set <acronym>TOAST</acronym> compression
methods.
With this option, all columns will be restored with the default
compression setting.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--no-unlogged-table-data</option></term>
<listitem>
<para>
Do not dump the contents of unlogged tables. This option has no
effect on whether or not the table definitions (schema) are dumped;
it only suppresses dumping the table data. Data in unlogged tables
is always excluded when dumping from a standby server.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--on-conflict-do-nothing</option></term>
<listitem>
<para>
Add <literal>ON CONFLICT DO NOTHING</literal> to
<command>INSERT</command> commands.
This option is not valid unless <option>--inserts</option>,
<option>--column-inserts</option> or
<option>--rows-per-insert</option> is also specified.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--quote-all-identifiers</option></term>
<listitem>
<para>
Force quoting of all identifiers. This option is recommended when
dumping a database from a server whose <productname>PostgreSQL</productname>
major version is different from <application>pg_dump</application>'s, or when
the output is intended to be loaded into a server of a different
major version. By default, <application>pg_dump</application> quotes only
identifiers that are reserved words in its own major version.
This sometimes results in compatibility issues when dealing with
servers of other versions that may have slightly different sets
of reserved words. Using <option>--quote-all-identifiers</option> prevents
such issues, at the price of a harder-to-read dump script.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--rows-per-insert=<replaceable class="parameter">nrows</replaceable></option></term>
<listitem>
<para>
Dump data as <command>INSERT</command> commands (rather than
<command>COPY</command>). Controls the maximum number of rows per
<command>INSERT</command> command. The value specified must be a
number greater than zero. Any error during reloading will cause only
rows that are part of the problematic <command>INSERT</command> to be
lost, rather than the entire table contents.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--section=<replaceable class="parameter">sectionname</replaceable></option></term>
<listitem>
<para>
Only dump the named section. The section name can be
<option>pre-data</option>, <option>data</option>, or <option>post-data</option>.
This option can be specified more than once to select multiple
sections. The default is to dump all sections.
</para>
<para>
The data section contains actual table data, large-object
contents, and sequence values.
Post-data items include definitions of indexes, triggers, rules,
and constraints other than validated check constraints.
Pre-data items include all other data definition items.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--serializable-deferrable</option></term>
<listitem>
<para>
Use a <literal>serializable</literal> transaction for the dump, to
ensure that the snapshot used is consistent with later database
states; but do this by waiting for a point in the transaction stream
at which no anomalies can be present, so that there isn't a risk of
the dump failing or causing other transactions to roll back with a
<literal>serialization_failure</literal>. See <xref linkend="mvcc"/>
for more information about transaction isolation and concurrency
control.
</para>
<para>
This option is not beneficial for a dump which is intended only for
disaster recovery. It could be useful for a dump used to load a
copy of the database for reporting or other read-only load sharing
while the original database continues to be updated. Without it the
dump may reflect a state which is not consistent with any serial
execution of the transactions eventually committed. For example, if
batch processing techniques are used, a batch may show as closed in
the dump without all of the items which are in the batch appearing.
</para>
<para>
This option will make no difference if there are no read-write
transactions active when pg_dump is started. If read-write
transactions are active, the start of the dump may be delayed for an
indeterminate length of time. Once running, performance with or
without the switch is the same.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--snapshot=<replaceable class="parameter">snapshotname</replaceable></option></term>
<listitem>
<para>
Use the specified synchronized snapshot when making a dump of the
database (see
<xref linkend="functions-snapshot-synchronization-table"/> for more
details).
</para>
<para>
This option is useful when needing to synchronize the dump with
a logical replication slot (see <xref linkend="logicaldecoding"/>)
or with a concurrent session.
</para>
<para>
In the case of a parallel dump, the snapshot name defined by this
option is used rather than taking a new snapshot.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--strict-names</option></term>
<listitem>
<para>
Require that each
extension (<option>-e</option>/<option>--extension</option>),
schema (<option>-n</option>/<option>--schema</option>) and
table (<option>-t</option>/<option>--table</option>) qualifier
match at least one extension/schema/table in the database to be dumped.
Note that if none of the extension/schema/table qualifiers find
matches, <application>pg_dump</application> will generate an error
even without <option>--strict-names</option>.
</para>
<para>
This option has no effect
on <option>-N</option>/<option>--exclude-schema</option>,
<option>-T</option>/<option>--exclude-table</option>,
or <option>--exclude-table-data</option>. An exclude pattern failing
to match any objects is not considered an error.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--use-set-session-authorization</option></term>
<listitem>
<para>
Output SQL-standard <command>SET SESSION AUTHORIZATION</command> commands
instead of <command>ALTER OWNER</command> commands to determine object
ownership. This makes the dump more standards-compatible, but
depending on the history of the objects in the dump, might not restore
properly. Also, a dump using <command>SET SESSION AUTHORIZATION</command>
will certainly require superuser privileges to restore correctly,
whereas <command>ALTER OWNER</command> requires lesser privileges.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-?</option></term>
<term><option>--help</option></term>
<listitem>
<para>
Show help about <application>pg_dump</application> command line
arguments, and exit.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
<para>
The following command-line options control the database connection parameters.
<variablelist>
<varlistentry>
<term><option>-d <replaceable class="parameter">dbname</replaceable></option></term>
<term><option>--dbname=<replaceable class="parameter">dbname</replaceable></option></term>
<listitem>
<para>
Specifies the name of the database to connect to. This is
equivalent to specifying <replaceable
class="parameter">dbname</replaceable> as the first non-option
argument on the command line. The <replaceable>dbname</replaceable>
can be a <link linkend="libpq-connstring">connection string</link>.
If so, connection string parameters will override any conflicting
command line options.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-h <replaceable class="parameter">host</replaceable></option></term>
<term><option>--host=<replaceable class="parameter">host</replaceable></option></term>
<listitem>
<para>
Specifies the host name of the machine on which the server is
running. If the value begins with a slash, it is used as the
directory for the Unix domain socket. The default is taken
from the <envar>PGHOST</envar> environment variable, if set,
else a Unix domain socket connection is attempted.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-p <replaceable class="parameter">port</replaceable></option></term>
<term><option>--port=<replaceable class="parameter">port</replaceable></option></term>
<listitem>
<para>
Specifies the TCP port or local Unix domain socket file
extension on which the server is listening for connections.
Defaults to the <envar>PGPORT</envar> environment variable, if
set, or a compiled-in default.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-U <replaceable>username</replaceable></option></term>
<term><option>--username=<replaceable class="parameter">username</replaceable></option></term>
<listitem>
<para>
User name to connect as.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-w</option></term>
<term><option>--no-password</option></term>
<listitem>
<para>
Never issue a password prompt. If the server requires
password authentication and a password is not available by
other means such as a <filename>.pgpass</filename> file, the
connection attempt will fail. This option can be useful in
batch jobs and scripts where no user is present to enter a
password.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-W</option></term>
<term><option>--password</option></term>
<listitem>
<para>
Force <application>pg_dump</application> to prompt for a
password before connecting to a database.
</para>
<para>
This option is never essential, since
<application>pg_dump</application> will automatically prompt
for a password if the server demands password authentication.
However, <application>pg_dump</application> will waste a
connection attempt finding out that the server wants a password.
In some cases it is worth typing <option>-W</option> to avoid the extra
connection attempt.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--role=<replaceable class="parameter">rolename</replaceable></option></term>
<listitem>
<para>
Specifies a role name to be used to create the dump.
This option causes <application>pg_dump</application> to issue a
<command>SET ROLE</command> <replaceable class="parameter">rolename</replaceable>
command after connecting to the database. It is useful when the
authenticated user (specified by <option>-U</option>) lacks privileges
needed by <application>pg_dump</application>, but can switch to a role with
the required rights. Some installations have a policy against
logging in directly as a superuser, and use of this option allows
dumps to be made without violating the policy.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1>
<title>Environment</title>
<variablelist>
<varlistentry>
<term><envar>PGDATABASE</envar></term>
<term><envar>PGHOST</envar></term>
<term><envar>PGOPTIONS</envar></term>
<term><envar>PGPORT</envar></term>
<term><envar>PGUSER</envar></term>
<listitem>
<para>
Default connection parameters.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><envar>PG_COLOR</envar></term>
<listitem>
<para>
Specifies whether to use color in diagnostic messages. Possible values
are <literal>always</literal>, <literal>auto</literal> and
<literal>never</literal>.
</para>
</listitem>
</varlistentry>
</variablelist>
<para>
This utility, like most other <productname>PostgreSQL</productname> utilities,
also uses the environment variables supported by <application>libpq</application>
(see <xref linkend="libpq-envars"/>).
</para>
</refsect1>
<refsect1 id="app-pgdump-diagnostics">
<title>Diagnostics</title>
<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, <xref
linkend="app-psql"/>. Also, any default connection settings and environment
variables used by the <application>libpq</application> front-end
library will apply.
</para>
<para>
The database activity of <application>pg_dump</application> is
normally collected by the statistics collector. If this is
undesirable, you can set parameter <varname>track_counts</varname>
to false via <envar>PGOPTIONS</envar> or the <literal>ALTER
USER</literal> command.
</para>
</refsect1>
<refsect1 id="pg-dump-notes">
<title>Notes</title>
<para>
If your database cluster has any local additions to the <literal>template1</literal> database,
be careful to restore the output of <application>pg_dump</application> into a
truly empty database; otherwise you are likely to get errors due to
duplicate definitions of the added objects. To make an empty database
without any local additions, copy from <literal>template0</literal> not <literal>template1</literal>,
for example:
<programlisting>
CREATE DATABASE foo WITH TEMPLATE template0;
</programlisting>
</para>
<para>
When a data-only dump is chosen and the option <option>--disable-triggers</option>
is used, <application>pg_dump</application> emits commands
to disable triggers on user tables before inserting the data,
and then commands to re-enable them after the data has been
inserted. If the restore is stopped in the middle, the system
catalogs might be left in the wrong state.
</para>
<para>
The dump file produced by <application>pg_dump</application>
does not contain the statistics used by the optimizer to make
query planning decisions. Therefore, it is wise to run
<command>ANALYZE</command> after restoring from a dump file
to ensure optimal performance; see <xref linkend="vacuum-for-statistics"/>
and <xref linkend="autovacuum"/> for more information.
</para>
<para>
Because <application>pg_dump</application> is used to transfer data
to newer versions of <productname>PostgreSQL</productname>, the output of
<application>pg_dump</application> can be expected to load into
<productname>PostgreSQL</productname> server versions newer than
<application>pg_dump</application>'s version. <application>pg_dump</application> can also
dump from <productname>PostgreSQL</productname> servers older than its own version.
(Currently, servers back to version 8.0 are supported.)
However, <application>pg_dump</application> cannot dump from
<productname>PostgreSQL</productname> servers newer than its own major version;
it will refuse to even try, rather than risk making an invalid dump.
Also, it is not guaranteed that <application>pg_dump</application>'s output can
be loaded into a server of an older major version &mdash; not even if the
dump was taken from a server of that version. Loading a dump file
into an older server may require manual editing of the dump file
to remove syntax not understood by the older server.
Use of the <option>--quote-all-identifiers</option> option is recommended
in cross-version cases, as it can prevent problems arising from varying
reserved-word lists in different <productname>PostgreSQL</productname> versions.
</para>
<para>
When dumping logical replication subscriptions,
<application>pg_dump</application> will generate <command>CREATE
SUBSCRIPTION</command> commands that use the <literal>connect = false</literal>
option, so that restoring the subscription does not make remote connections
for creating a replication slot or for initial table copy. That way, the
dump can be restored without requiring network access to the remote
servers. It is then up to the user to reactivate the subscriptions in a
suitable way. If the involved hosts have changed, the connection
information might have to be changed. It might also be appropriate to
truncate the target tables before initiating a new full table copy.
</para>
<para>
<application>pg_dump</application> also supports a
<literal>--binary-upgrade</> option for upgrade utility usage.
</para>
</refsect1>
<refsect1 id="pg-dump-examples" xreflabel="Examples">
<title>Examples</title>
<para>
To dump a database called <literal>mydb</literal> into an SQL-script file:
<screen>
<prompt>$</prompt> <userinput>pg_dump mydb &gt; db.sql</userinput>
</screen>
</para>
<para>
To reload such a script into a (freshly created) database named
<literal>newdb</literal>:
<screen>
<prompt>$</prompt> <userinput>psql -d newdb -f db.sql</userinput>
</screen>
</para>
<para>
To dump a database into a custom-format archive file:
<screen>
<prompt>$</prompt> <userinput>pg_dump -Fc mydb &gt; db.dump</userinput>
</screen>
</para>
<para>
To dump a database into a directory-format archive:
<screen>
<prompt>$</prompt> <userinput>pg_dump -Fd mydb -f dumpdir</userinput>
</screen>
</para>
<para>
To dump a database into a directory-format archive in parallel with
5 worker jobs:
<screen>
<prompt>$</prompt> <userinput>pg_dump -Fd mydb -j 5 -f dumpdir</userinput>
</screen>
</para>
<para>
To reload an archive file into a (freshly created) database named
<literal>newdb</literal>:
<screen>
<prompt>$</prompt> <userinput>pg_restore -d newdb db.dump</userinput>
</screen>
</para>
<para>
To reload an archive file into the same database it was dumped from,
discarding the current contents of that database:
<screen>
<prompt>$</prompt> <userinput>pg_restore -d postgres --clean --create db.dump</userinput>
</screen>
</para>
<para>
To dump a single table named <literal>mytab</literal>:
<screen>
<prompt>$</prompt> <userinput>pg_dump -t mytab mydb &gt; db.sql</userinput>
</screen>
</para>
<para>
To dump all tables whose names start with <literal>emp</literal> in the
<literal>detroit</literal> schema, except for the table named
<literal>employee_log</literal>:
<screen>
<prompt>$</prompt> <userinput>pg_dump -t 'detroit.emp*' -T detroit.employee_log mydb &gt; db.sql</userinput>
</screen>
</para>
<para>
To dump all schemas whose names start with <literal>east</literal> or
<literal>west</literal> and end in <literal>gsm</literal>, excluding any schemas whose
names contain the word <literal>test</literal>:
<screen>
<prompt>$</prompt> <userinput>pg_dump -n 'east*gsm' -n 'west*gsm' -N '*test*' mydb &gt; db.sql</userinput>
</screen>
</para>
<para>
The same, using regular expression notation to consolidate the switches:
<screen>
<prompt>$</prompt> <userinput>pg_dump -n '(east|west)*gsm' -N '*test*' mydb &gt; db.sql</userinput>
</screen>
</para>
<para>
To dump all database objects except for tables whose names begin with
<literal>ts_</literal>:
<screen>
<prompt>$</prompt> <userinput>pg_dump -T 'ts_*' mydb &gt; db.sql</userinput>
</screen>
</para>
<para>
To specify an upper-case or mixed-case name in <option>-t</option> and related
switches, you need to double-quote the name; else it will be folded to
lower case (see <xref linkend="app-psql-patterns"/> below). But
double quotes are special to the shell, so in turn they must be quoted.
Thus, to dump a single table with a mixed-case name, you need something
like
<screen>
<prompt>$</prompt> <userinput>pg_dump -t "\"MixedCaseName\"" mydb &gt; mytab.sql</userinput>
</screen></para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="app-pg-dumpall"/></member>
<member><xref linkend="app-pgrestore"/></member>
<member><xref linkend="app-psql"/></member>
</simplelist>
</refsect1>
</refentry>