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NAME

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

SYNOPSIS

       pg_dump [connection-option...] [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 reconstruct 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 products.

       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 architectures.

       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 database 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.

       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). Table data, large objects, and
           sequence values are dumped.

           This option is similar to, but for historical reasons not identical to, specifying
           --section=data.

       -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 outputting the commands for
           creating them. (Restore might generate some harmless error messages, if any objects
           were not present in the destination database.)

           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 in the
           destination installation you connect to before running the script.) If --clean is also
           specified, the script drops and recreates the target database before reconnecting to
           it.

           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. 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 pg_dump and must not exist before.

       -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-format archive suitable for input into pg_restore. 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.

           d, directory
               Output a directory-format archive suitable for input into pg_restore. 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 pg_restore 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 gzip tool. This format is compressed by
               default.

           t, tar
               Output a tar-format archive suitable for input into pg_restore. 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 and has a limit of 8 GB on the size of individual tables. Also, the
               relative order of table data items cannot be changed during restore.

       -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 specified, 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 Patterns), 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 EXAMPLES.

               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.

           This option is the inverse of --data-only. It is similar to, but for historical
           reasons not identical to, specifying --section=pre-data --section=post-data.

           (Do not confuse this with the --schema option, which uses the word “schema” in a
           different meaning.)

           To exclude table data for only a subset of tables in the database, see
           --exclude-table-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 or foreign tables) 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), 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 EXAMPLES.

           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.

       -V, --version
           Print the pg_dump version and exit.

       -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 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 gzip; but the default is not to compress. 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.

       --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. However, 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 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.

           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.

       --exclude-table-data=table
           Do not dump data for any tables matching the table pattern. The pattern is interpreted
           according to the same rules as for -t.  --exclude-table-data 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.

           To exclude data for all tables in the database, see --schema-only.

       --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.
           However, 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.

       --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-security-labels
           Do not dump security labels.

       --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.

       --no-unlogged-table-data
           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.

       --quote-all-identifiers
           Force quoting of all identifiers. This may be useful when dumping a database for
           migration to a future version that may have introduced additional keywords.

       --section=sectionname
           Only dump the named section. The section name can be pre-data, data, or post-data.
           This option can be specified more than once to select multiple sections. The default
           is to dump all sections.

           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.

       --serializable-deferrable
           Use a serializable 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
           serialization_failure. See Chapter 13, Concurrency Control, in the documentation for
           more information about transaction isolation and concurrency control.

           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.

           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.

       --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.

       --dump-nodes

               Note
               The following description applies only to Postgres-XC
           Output commands to create nodes and node groups. This option may be used while adding
           a new coordinator to an existing Postgres-XC cluster.

       -?, --help
           Show help about pg_dump command line arguments, and exit.

       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 authentication. 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 ROLErolename command after connecting 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 Section 32.14, “Environment Variables”, 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 system 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 format 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 optimal performance; see Section 22.1.3, “Updating Planner
       Statistics”, in the documentation and Section 22.1.6, “The Autovacuum Daemon”, 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 versionnot 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 dump a database into a directory-format archive:

           $ pg_dump -Fd mydb -f dumpdir

       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). 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)