PG_DUMP(1)						  PostgreSQL Client Applications						PG_DUMP(1)

NAME

       pg_dump - extract a PostgreSQL database into a script file or other archive file

SYNOPSIS

       pg_dump [ option... ]  [ dbname ]

DESCRIPTION

       pg_dump	is  a  utility	for backing up a PostgreSQL database. It makes consistent backups even if the database is being used concurrently.
       pg_dump does not block other users accessing the database (readers or writers).

       Dumps can be output in script or archive file formats. Script dumps are plain-text files containing the SQL  commands  required	to  recon-
       struct the database to the state it was in at the time it was saved. To restore from such a script, feed it to psql(1). Script files can be
       used to reconstruct the database even on other machines and other architectures; with some modifications even on other SQL  database  prod-
       ucts.

       The  alternative  archive file formats must be used with pg_restore(1) to rebuild the database. They allow pg_restore 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 archi-
       tectures.

       When  used  with one of the archive file formats and combined with pg_restore, pg_dump provides a flexible archival and transfer mechanism.
       pg_dump can be used to backup an entire database, then pg_restore can be used to examine the archive and/or select which parts of the data-
       base are to be restored. The most flexible output file format is the ``custom'' format (-Fc). It allows for selection and reordering of all
       archived items, and is compressed by default. The tar format (-Ft) is not compressed and it is not possible to reorder data  when  loading,
       but it is otherwise quite flexible; moreover, it can be manipulated with standard Unix tools such as tar.

       While  running  pg_dump, one should examine the output for any warnings (printed on standard error), especially in light of the limitations
       listed below.

OPTIONS

       The following command-line options control the content and format of the output.

       dbname Specifies the name of the database to be dumped. If this is not specified, the environment variable PGDATABASE is used. If  that	is
	      not set, the user name specified for the connection is used.

       -a

       --data-only
	      Dump only the data, not the schema (data definitions).

	      This  option  is	only  meaningful  for  the  plain-text	format.  For the archive formats, you can specify the option when you call
	      pg_restore.

       -b

       --blobs
	      Include large objects in the dump. This is the default behavior except when --schema, --table, or --schema-only is specified, so the
	      -b switch is only useful to add large objects to selective dumps.

       -c

       --clean
	      Output commands to clean (drop) database objects prior to (the commands for) creating them.

	      This  option  is	only  meaningful  for  the  plain-text	format.  For the archive formats, you can specify the option when you call
	      pg_restore.

       -C

       --create
	      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 you connect to before running the script.)

	      This  option  is	only  meaningful  for  the  plain-text	format.  For the archive formats, you can specify the option when you call
	      pg_restore.

       -E encoding

       --encoding=encoding
	      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 PGCLIENTENCODING environment variable to the desired dump encoding.)

       -f file

       --file=file
	      Send output to the specified file. If this is omitted, the standard output is used.

       -F format

       --format=format
	      Selects the format of the output.  format can be one of the following:

	      p

	      plain  Output a plain-text SQL script file (the default).

	      c

	      custom Output  a custom archive suitable for input into pg_restore. This is the most flexible format in that it allows reordering of
		     loading data as well as object definitions. This format is also compressed by default.

	      t

	      tar    Output a tar archive suitable for input into pg_restore. Using this archive format  allows  reordering  and/or  exclusion	of
		     database objects at the time the database is restored. It is also possible to limit which data is reloaded at restore time.

       -i

       --ignore-version
	      A deprecated option that is now ignored.

       -n schema

       --schema=schema
	      Dump only schemas matching schema; this selects both the schema itself, and all its contained objects. When this option is not spec-
	      ified, all non-system schemas in the target database will be dumped. Multiple  schemas  can  be  selected  by  writing  multiple	-n
	      switches.  Also,	the  schema parameter is interpreted as a pattern according to the same rules used by psql's d commands (see Pat-
	      terns [psql(1)]), 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.

	      Note:  When  -n  is  specified, pg_dump 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.

	      Note:  Non-schema  objects  such	as  blobs are not dumped when -n is specified. You can add blobs back to the dump with the --blobs
	      switch.

       -N schema

       --exclude-schema=schema
	      Do not dump any schemas matching the schema pattern. The pattern is interpreted according to the same rules as for -n.   -N  can	be
	      given more than once to exclude schemas matching any of several patterns.

	      When  both -n and -N are given, the behavior is to dump just the schemas that match at least one -n switch but no -N switches. If -N
	      appears without -n, then schemas matching -N are excluded from what is otherwise a normal dump.

       -o

       --oids Dump object identifiers (OIDs) as part of the data for every table. Use this option if your application references the  OID  columns
	      in some way (e.g., in a foreign key constraint).	Otherwise, this option should not be used.

       -O

       --no-owner
	      Do  not  output  commands to set ownership of objects to match the original database.  By default, pg_dump issues ALTER OWNER or SET
	      SESSION AUTHORIZATION 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 -O.

	      This option is only meaningful for the plain-text format. For the archive  formats,  you	can  specify  the  option  when  you  call
	      pg_restore.

       -R

       --no-reconnect
	      This option is obsolete but still accepted for backwards compatibility.

       -s

       --schema-only
	      Dump only the object definitions (schema), not data.

       -S username

       --superuser=username
	      Specify  the  superuser  user  name to use when disabling triggers.  This is only relevant if --disable-triggers is used.  (Usually,
	      it's better to leave this out, and instead start the resulting script as superuser.)

       -t table

       --table=table
	      Dump only tables (or views or sequences) matching table. Multiple tables can be selected by writing multiple -t switches. Also,  the
	      table parameter is interpreted as a pattern according to the same rules used by psql's d commands (see Patterns [psql(1)]), so mul-
	      tiple tables can also be selected by writing wildcard characters in the pattern. When using wildcards, be careful to quote the  pat-
	      tern if needed to prevent the shell from expanding the wildcards.

	      The  -n  and  -N switches have no effect when -t is used, because tables selected by -t will be dumped regardless of those switches,
	      and non-table objects will not be dumped.

	      Note: When -t is specified, pg_dump 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.

	      Note: The behavior of the -t switch is not entirely upward compatible with pre-8.2 PostgreSQL versions.  Formerly,  writing  -t  tab
	      would dump all tables named tab, but now it just dumps whichever one is visible in your default search path. To get the old behavior
	      you can write -t '*.tab'. Also, you must write something like -t sch.tab to select a table in a particular schema, rather  than  the
	      old locution of -n sch -t tab.

       -T table

       --exclude-table=table
	      Do  not  dump  any  tables  matching the table pattern. The pattern is interpreted according to the same rules as for -t.  -T can be
	      given more than once to exclude tables matching any of several patterns.

	      When both -t and -T are given, the behavior is to dump just the tables that match at least one -t switch but no -T switches.  If	-T
	      appears without -t, then tables matching -T are excluded from what is otherwise a normal dump.

       -v

       --verbose
	      Specifies  verbose  mode.  This  will  cause  pg_dump  to output detailed object comments and start/stop times to the dump file, and
	      progress messages to standard error.

       -x

       --no-privileges

       --no-acl
	      Prevent dumping of access privileges (grant/revoke commands).

       -Z 0..9

       --compress=0..9
	      Specify the compression level to use. Zero means no compression.	For the custom archive format, this specifies compression of indi-
	      vidual  table-data  segments, and the default is to compress at a moderate level.  For plain text output, setting a nonzero compres-
	      sion level causes the entire output file to be compressed, as though it had been fed through gzip; but the default is  not  to  com-
	      press.  The tar archive format currently does not support compression at all.

       --binary-upgrade
	      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.

       --inserts
	      Dump data as INSERT commands (rather than COPY). This will make restoration very slow; it is mainly useful for making dumps that can
	      be loaded into non-PostgreSQL databases.	Also, since this option generates a separate command for each row, an error in reloading a
	      row causes only that row to be lost rather than the entire table contents.  Note that the restore might fail altogether if you  have
	      rearranged column order.	The --column-inserts option is safe against column order changes, though even slower.

       --column-inserts

       --attribute-inserts
	      Dump  data  as  INSERT  commands with explicit column names (INSERT INTO table (column, ...) VALUES ...). This will make restoration
	      very slow; it is mainly useful for making dumps that can be loaded into non-PostgreSQL databases.  Also, since this option generates
	      a separate command for each row, an error in reloading a row causes only that row to be lost rather than the entire table contents.

       --disable-dollar-quoting
	      This option disables the use of dollar quoting for function bodies, and forces them to be quoted using SQL standard string syntax.

       --disable-triggers
	      This  option is only relevant when creating a data-only dump.  It instructs pg_dump to include commands to temporarily disable trig-
	      gers 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.

	      Presently,  the commands emitted for --disable-triggers must be done as superuser. So, you should also specify a superuser name with
	      -S, or preferably be careful to start the resulting script as a superuser.

	      This option is only meaningful for the plain-text format. For the archive  formats,  you	can  specify  the  option  when  you  call
	      pg_restore.

       --lock-wait-timeout=timeout
	      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 timeout. The timeout may be specified in any of the formats  accepted  by  SET	statement_timeout.  (Allowed  values  vary
	      depending  on  the server version you are dumping from, but an integer number of milliseconds is accepted by all versions since 7.3.
	      This option is ignored when dumping from a pre-7.3 server.)

       --no-tablespaces
	      Do not output commands to select tablespaces.  With this option, all objects will be created in whichever tablespace is the  default
	      during restore.

	      This  option  is	only  meaningful  for  the  plain-text	format.  For the archive formats, you can specify the option when you call
	      pg_restore.

       --use-set-session-authorization
	      Output SQL-standard SET SESSION AUTHORIZATION commands instead of ALTER OWNER 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 SET SESSION AUTHORIZATION will certainly require superuser privileges to  restore  correctly,  whereas  ALTER  OWNER  requires
	      lesser privileges.

       The following command-line options control the database connection parameters.

       -h host

       --host=host
	      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 PGHOST environment variable, if set, else a Unix domain socket	connection
	      is attempted.

       -p port

       --port=port
	      Specifies the TCP port or local Unix domain socket file extension on which the server is listening for connections.  Defaults to the
	      PGPORT environment variable, if set, or a compiled-in default.

       -U username

       --username=username
	      User name to connect as.

       -w

       --no-password
	      Never issue a password prompt. If the server requires password authentication and a password is not available by other means such as
	      a  .pgpass  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.

       -W

       --password
	      Force pg_dump to prompt for a password before connecting to a database.

	      This option is never essential, since pg_dump will automatically prompt for a password if the server  demands  password  authentica-
	      tion.   However,	pg_dump  will  waste a connection attempt finding out that the server wants a password.  In some cases it is worth
	      typing -W to avoid the extra connection attempt.

       --role=rolename
	      Specifies a role name to be used to create the dump.  This option causes pg_dump to issue a SET ROLE rolename command after connect-
	      ing  to  the database. It is useful when the authenticated user (specified by -U) lacks privileges needed by pg_dump, 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.

ENVIRONMENT

       PGDATABASE

       PGHOST

       PGOPTIONS

       PGPORT

       PGUSER Default connection parameters.

       This utility, like most other PostgreSQL utilities, also uses the environment variables supported by libpq (see in the documentation).

DIAGNOSTICS

       pg_dump	internally executes SELECT statements. If you have problems running pg_dump, make sure you are able to select information from the
       database using, for example, psql(1). Also, any default connection settings and environment variables used by the libpq	front-end  library
       will apply.

       The  database  activity	of  pg_dump  is  normally  collected  by  the  statistics collector. If this is undesirable, you can set parameter
       track_counts to false via PGOPTIONS or the ALTER USER command.

NOTES

       If your database cluster has any local additions to the template1 database, be careful to restore the output of pg_dump 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 template0 not template1, for example:

       CREATE DATABASE foo WITH TEMPLATE template0;

       When a data-only dump is chosen and the option --disable-triggers is used, pg_dump 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 sys-
       tem catalogs might be left in the wrong state.

       Members of tar archives are limited to a size less than 8 GB.  (This is an inherent limitation of the tar file format.) Therefore this for-
       mat  cannot  be used if the textual representation of any one table exceeds that size. The total size of a tar archive and any of the other
       output formats is not limited, except possibly by the operating system.

       The dump file produced by pg_dump does not contain the statistics used by the optimizer to make query planning decisions. Therefore, it	is
       wise to run ANALYZE after restoring from a dump file to ensure good performance; see in the documentation and in the documentation for more
       information.  The dump file also does not contain any ALTER DATABASE ... SET commands; these settings are dumped  by  pg_dumpall(1),  along
       with database users and other installation-wide settings.

       Because	pg_dump  is  used  to transfer data to newer versions of PostgreSQL, the output of pg_dump can be expected to load into PostgreSQL
       server versions newer than pg_dump's version. pg_dump can also dump from PostgreSQL  servers  older  than  its  own  version.   (Currently,
       servers back to version 7.0 are supported.)  However, pg_dump cannot dump from PostgreSQL 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 pg_dump's output can be loaded into a  server
       of  an  older  major  version -- 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.

EXAMPLES

       To dump a database called mydb into a SQL-script file:

       $ pg_dump mydb > db.sql

       To reload such a script into a (freshly created) database named newdb:

       $ psql -d newdb -f db.sql

       To dump a database into a custom-format archive file:

       $ pg_dump -Fc mydb > db.dump

       To reload an archive file into a (freshly created) database named newdb:

       $ pg_restore -d newdb db.dump

       To dump a single table named mytab:

       $ pg_dump -t mytab mydb > db.sql

       To dump all tables whose names start with emp in the detroit schema, except for the table named employee_log:

       $ pg_dump -t 'detroit.emp*' -T detroit.employee_log mydb > db.sql

       To dump all schemas whose names start with east or west and end in gsm, excluding any schemas whose names contain the word test:

       $ pg_dump -n 'east*gsm' -n 'west*gsm' -N '*test*' mydb > db.sql

       The same, using regular expression notation to consolidate the switches:

       $ pg_dump -n '(east|west)*gsm' -N '*test*' mydb > db.sql

       To dump all database objects except for tables whose names begin with ts_:

       $ pg_dump -T 'ts_*' mydb > db.sql

       To specify an upper-case or mixed-case name in -t and related switches, you need to double-quote the name; else it will be folded to  lower
       case  (see  Patterns  [psql(1)]). 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

       $ pg_dump -t '"MixedCaseName"' mydb > mytab.sql

SEE ALSO

       pg_dumpall(1), pg_restore(1), psql(1)

Application							    2010-05-14								PG_DUMP(1)