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pg_dump

   pg_dump — export a PostgreSQL database as an SQL script or to other
   formats

Synopsis

   pg_dump [connection-option...] [option...] [dbname]

Description

   pg_dump is a utility for exporting a PostgreSQL database. It makes
   consistent exports even if the database is being used concurrently.
   pg_dump does not block other users accessing the database (readers or
   writers). Note, however, that except in simple cases, pg_dump is
   generally not the right choice for taking regular backups of production
   databases. See Chapter 25 for further discussion.

   pg_dump only dumps a single database. To export an entire cluster, or
   to export global objects that are common to all databases in a cluster
   (such as roles and tablespaces), use pg_dumpall.

   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. 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 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 export 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
   formats are the “custom” format (-Fc) and the “directory” format (-Fd).
   They allow for selection and reordering of all archived items, support
   parallel restoration, and are compressed by default. The “directory”
   format is the only format that supports parallel dumps.

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

Warning

   Restoring a dump causes the destination to execute arbitrary code of
   the source superusers' choice. Partial dumps and partial restores do
   not limit that. If the source superusers are not trusted, the dumped
   SQL statements must be inspected before restoring. Non-plain-text dumps
   can be inspected by using pg_restore's --file option. Note that the
   client running the dump and restore need not trust the source or
   destination superusers.

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) or
          statistics. 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
          --large-objects
          --blobs (deprecated)
          Include large objects in the dump. This is the default behavior
          except when --schema, --table, --schema-only, --statistics-only,
          or --no-data is specified. The -b switch is therefore only
          useful to add large objects to dumps where a specific schema or
          table has been requested. Note that large objects are considered
          data and therefore will be included when --data-only is used,
          but not when --schema-only or --statistics-only is.

   -B
          --no-large-objects
          --no-blobs (deprecated)
          Exclude large objects in the dump.

          When both -b and -B are given, the behavior is to output large
          objects, when data is being dumped, see the -b documentation.

   -c
          --clean
          Output commands to DROP all the dumped database objects prior to
          outputting the commands for creating them. This option is useful
          when the restore is to overwrite an existing database. If any of
          the objects do not exist in the destination database, ignorable
          error messages will be reported during restore, unless
          --if-exists is also specified.

          This option is ignored when emitting an archive (non-text)
          output file. 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.

          With --create, the output also includes the database's comment
          if any, and any configuration variable settings that are
          specific to this database, that is, any ALTER DATABASE ... SET
          ... and ALTER ROLE ... IN DATABASE ... SET ... commands that
          mention this database. Access privileges for the database itself
          are also dumped, unless --no-acl is specified.

          This option is ignored when emitting an archive (non-text)
          output file. For the archive formats, you can specify the option
          when you call pg_restore.

   -e pattern
          --extension=pattern
          Dump only extensions matching pattern. 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 -e switches. The pattern parameter is interpreted as a
          pattern according to the same rules used by psql's \d commands
          (see 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.

          Any configuration relation registered by
          pg_extension_config_dump is included in the dump if its
          extension is specified by --extension.

Note

          When -e is specified, pg_dump 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.

   -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.) The
          supported encodings are described in Section 23.3.1.

   -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 large object 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, lz4, or zstd tools. This
                format is compressed by default using gzip and also
                supports parallel dumps.

        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. Also, when using tar format
                the relative order of table data items cannot be changed
                during restore.

   -j njobs
          --jobs=njobs
          Run the dump in parallel by dumping njobs 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.

          pg_dump will open njobs + 1 connections to the database, so make
          sure your max_connections setting is high enough to accommodate
          all connections.

          Requesting exclusive locks on database objects while running a
          parallel dump could cause the dump to fail. The reason is that
          the pg_dump leader process requests shared locks (ACCESS SHARE)
          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 leader 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 pg_dump worker process
          requests another shared lock using the NOWAIT 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 pg_dump has no choice
          but to abort the dump.

          To perform a parallel dump, the database server needs to support
          synchronized snapshots, a feature that was introduced in
          PostgreSQL 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. pg_dump -j uses
          multiple database connections; it connects to the database once
          with the leader 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.

   -n pattern
          --schema=pattern
          Dump only schemas matching pattern; 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. The pattern 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 below.

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 large objects are not dumped when -n
          is specified. You can add large objects back to the dump with
          the --large-objects switch.

   -N pattern
          --exclude-schema=pattern
          Do not dump any schemas matching 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
          --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 ignored when emitting an archive (non-text)
          output file. 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 or
          statistics.

          This option cannot be used with --data-only or
          --statistics-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 relevant only if --disable-triggers is used. (Usually,
          it's better to leave this out, and instead start the resulting
          script as superuser.)

   -t pattern
          --table=pattern
          Dump only tables with names matching pattern. Multiple tables
          can be selected by writing multiple -t switches. The pattern
          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 below.

          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
          --include-foreign-data.

          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.

   -T pattern
          --exclude-table=pattern
          Do not dump any tables matching 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. Repeating the option
          causes additional debug-level messages to appear on 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 level
          -Z method[:detail]
          --compress=level
          --compress=method[:detail]
          Specify the compression method and/or the compression level to
          use. The compression method can be set to gzip, lz4, zstd, or
          none for no compression. A compression detail string can
          optionally be specified. If the detail string is an integer, it
          specifies the compression level. Otherwise, it should be a
          comma-separated list of items, each of the form keyword or
          keyword=value. Currently, the supported keywords are level and
          long.

          If no compression level is specified, the default compression
          level will be used. If only a level is specified without
          mentioning an algorithm, gzip compression will be used if the
          level is greater than 0, and no compression will be used if the
          level is 0.

          For the custom and directory archive formats, this specifies
          compression of individual table-data segments, and the default
          is to compress using gzip 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, lz4, or zstd; but the default is not to compress. With
          zstd compression, long mode may improve the compression ratio,
          at the cost of increased memory use.

          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. Any error during restoring
          will cause only rows that are part of the problematic INSERT 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 relevant only when creating a dump that includes
          data but does not include schema. It instructs pg_dump to
          include commands to temporarily disable triggers on the target
          tables while the data is restored. Use this if you have
          referential integrity checks or other triggers on the tables
          that you do not want to invoke during data restore.

          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 ignored when emitting an archive (non-text)
          output file. For the archive formats, you can specify the option
          when you call pg_restore.

   --enable-row-security
          This option is relevant only when dumping the contents of a
          table which has row security. By default, pg_dump will set
          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
          pg_dump to set row_security to on instead, allowing the user to
          dump the parts of the contents of the table that they have
          access to.

          Note that if you use this option currently, you probably also
          want the dump be in INSERT format, as the COPY FROM during
          restore does not support row security.

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

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

   --exclude-table-and-children=pattern
          This is the same as the -T/--exclude-table option, except that
          it also excludes any partitions or inheritance child tables of
          the table(s) matching the pattern.

   --exclude-table-data=pattern
          Do not dump data for any tables matching 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 or --statistics-only.

   --exclude-table-data-and-children=pattern
          This is the same as the --exclude-table-data option, except that
          it also excludes data of any partitions or inheritance child
          tables of the table(s) matching the pattern.

   --extra-float-digits=ndigits
          Use the specified value of extra_float_digits when dumping
          floating-point data, instead of the maximum available precision.
          Routine dumps made for backup purposes should not use this
          option.

   --filter=filename
          Specify a filename from which to read patterns for objects to
          include or exclude from the dump. The patterns are interpreted
          according to the same rules as the corresponding options:
          -t/--table, --table-and-children, -T/--exclude-table, and
          --exclude-table-and-children for tables, -n/--schema and
          -N/--exclude-schema for schemas, --include-foreign-data for data
          on foreign servers, --exclude-table-data and
          --exclude-table-data-and-children for table data, and
          -e/--extension and --exclude-extension for extensions. To read
          from STDIN, use - as the filename. The --filter option can be
          specified in conjunction with the above listed options for
          including or excluding objects, and can also be specified more
          than once for multiple filter files.

          The file lists one object pattern per row, with the following
          format:

{ include | exclude } { extension | foreign_data | table | table_and_children |
table_data | table_data_and_children | schema } PATTERN

          The first keyword specifies whether the objects matched by the
          pattern are to be included or excluded. The second keyword
          specifies the type of object to be filtered using the pattern:

          + extension: extensions. This works like the -e/--extension or
            --exclude-extension option.
          + foreign_data: data on foreign servers. This works like the
            --include-foreign-data option. This keyword can only be used
            with the include keyword.
          + table: tables. This works like the -t/--table or
            -T/--exclude-table option.
          + table_and_children: tables including any partitions or
            inheritance child tables. This works like the
            --table-and-children or --exclude-table-and-children option.
          + table_data: table data of any tables matching pattern. This
            works like the --exclude-table-data option. This keyword can
            only be used with the exclude keyword.
          + table_data_and_children: table data of any tables matching
            pattern as well as any partitions or inheritance children of
            the table(s). This works like the
            --exclude-table-data-and-children option. This keyword can
            only be used with the exclude keyword.
          + schema: schemas. This works like the -n/--schema or
            -N/--exclude-schema option.

          Lines starting with # are considered comments and ignored.
          Comments can be placed after an object pattern row as well.
          Blank lines are also ignored. See Patterns for how to perform
          quoting in patterns.

          Example files are listed below in the Examples section.

   --if-exists
          Use DROP ... IF EXISTS commands to drop objects in --clean mode.
          This suppresses “does not exist” errors that might otherwise be
          reported. This option is not valid unless --clean is also
          specified.

   --include-foreign-data=foreignserver
          Dump the data for any foreign table with a foreign server
          matching foreignserver pattern. Multiple foreign servers can be
          selected by writing multiple --include-foreign-data switches.
          Also, the foreignserver parameter is interpreted as a pattern
          according to the same rules used by psql's \d commands (see
          Patterns), 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 Examples below. The
          only exception is that an empty pattern is disallowed.

Note

          Using wildcards in --include-foreign-data may result in access
          to unexpected foreign servers. Also, to use this option
          securely, make sure that the named server must have a trusted
          owner.

Note

          When --include-foreign-data is specified, pg_dump 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.

   --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. Any error during
          restoring will cause only rows that are part of the problematic
          INSERT 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.

   --load-via-partition-root
          When dumping data for a table partition, make the COPY or INSERT
          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 restoring 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.

   --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
          formats vary depending on the server version you are dumping
          from, but an integer number of milliseconds is accepted by all
          versions.)

   --no-comments
          Do not dump COMMENT commands.

   --no-data
          Do not dump data.

   --no-policies
          Do not dump row security policies.

   --no-publications
          Do not dump publications.

   --no-schema
          Do not dump schema (data definitions).

   --no-security-labels
          Do not dump security labels.

   --no-statistics
          Do not dump statistics. This is the default.

   --no-subscriptions
          Do not dump subscriptions.

   --no-sync
          By default, pg_dump will wait for all files to be written safely
          to disk. This option causes pg_dump 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.

   --no-table-access-method
          Do not output commands to select table access methods. With this
          option, all objects will be created with whichever table access
          method is the default during restore.

          This option is ignored when emitting an archive (non-text)
          output file. For the archive formats, you can specify the option
          when you call pg_restore.

   --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 ignored when emitting an archive (non-text)
          output file. For the archive formats, you can specify the option
          when you call pg_restore.

   --no-toast-compression
          Do not output commands to set TOAST compression methods. With
          this option, all columns will be restored with the default
          compression setting.

   --no-unlogged-table-data
          Do not dump the contents of unlogged tables and sequences. This
          option has no effect on whether or not the table and sequence
          definitions (schema) are dumped; it only suppresses dumping the
          table and sequence data. Data in unlogged tables and sequences
          is always excluded when dumping from a standby server.

   --on-conflict-do-nothing
          Add ON CONFLICT DO NOTHING to INSERT commands. This option is
          not valid unless --inserts, --column-inserts or
          --rows-per-insert is also specified.

   --quote-all-identifiers
          Force quoting of all identifiers. This option is recommended
          when dumping a database from a server whose PostgreSQL major
          version is different from pg_dump's, or when the output is
          intended to be loaded into a server of a different major
          version. By default, pg_dump 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 --quote-all-identifiers prevents such issues, at
          the price of a harder-to-read dump script.

   --restrict-key=restrict_key
          Use the provided string as the psql \restrict key in the dump
          output. This can only be specified for plain-text dumps, i.e.,
          when --format is set to plain or the --format option is omitted.
          If no restrict key is specified, pg_dump will generate a random
          one as needed. Keys may contain only alphanumeric characters.

          This option is primarily intended for testing purposes and other
          scenarios that require repeatable output (e.g., comparing dump
          files). It is not recommended for general use, as a malicious
          server with advance knowledge of the key may be able to inject
          arbitrary code that will be executed on the machine that runs
          psql with the dump output.

   --rows-per-insert=nrows
          Dump data as INSERT commands (rather than COPY). Controls the
          maximum number of rows per INSERT command. The value specified
          must be a number greater than zero. Any error during restoring
          will cause only rows that are part of the problematic INSERT to
          be lost, rather than the entire table contents.

   --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, sequence values, and statistics for tables,
          materialized views, and foreign tables. Post-data items include
          definitions of indexes, triggers, rules, statistics for indexes,
          and constraints other than validated check and not-null
          constraints. Pre-data items include all other data definition
          items.

   --sequence-data
          Include sequence data in the dump. This is the default behavior
          except when --no-data, --schema-only, or --statistics-only is
          specified.

   --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 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.

   --snapshot=snapshotname
          Use the specified synchronized snapshot when making a dump of
          the database (see Table 9.100 for more details).

          This option is useful when needing to synchronize the dump with
          a logical replication slot (see Chapter 47) or with a concurrent
          session.

          In the case of a parallel dump, the snapshot name defined by
          this option is used rather than taking a new snapshot.

   --statistics
          Dump statistics.

   --statistics-only
          Dump only the statistics, not the schema (data definitions) or
          data. Statistics for tables, materialized views, foreign tables,
          and indexes are dumped.

   --strict-names
          Require that each extension (-e/--extension), schema
          (-n/--schema) and table (-t/--table) pattern match at least one
          extension/schema/table in the database to be dumped. This also
          applies to filters used with --filter. Note that if none of the
          extension/schema/table patterns find matches, pg_dump will
          generate an error even without --strict-names.

          This option has no effect on --exclude-extension,
          -N/--exclude-schema, -T/--exclude-table, or
          --exclude-table-data. An exclude pattern failing to match any
          objects is not considered an error.

   --sync-method=method
          When set to fsync, which is the default, pg_dump
          --format=directory will recursively open and synchronize all
          files in the archive directory.

          On Linux, syncfs may be used instead to ask the operating system
          to synchronize the whole file system that contains the archive
          directory. See recovery_init_sync_method for information about
          the caveats to be aware of when using syncfs.

          This option has no effect when --no-sync is used or --format is
          not set to directory.

   --table-and-children=pattern
          This is the same as the -t/--table option, except that it also
          includes any partitions or inheritance child tables of the
          table(s) matching the pattern.

   --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.

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

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

   -d dbname
          --dbname=dbname
          Specifies the name of the database to connect to. This is
          equivalent to specifying dbname as the first non-option argument
          on the command line. The dbname can be a connection string. If
          so, connection string parameters will override any conflicting
          command line options.

   -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 ROLE rolename 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.

   PG_COLOR
          Specifies whether to use color in diagnostic messages. Possible
          values are always, auto and never.

   This utility, like most other PostgreSQL utilities, also uses the
   environment variables supported by libpq (see Section 32.15).

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. 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
   cumulative statistics system. 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 dump without schema 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.

   If --statistics is specified, pg_dump will include most optimizer
   statistics in the resulting dump file. However, some statistics may not
   be included, such as those created explicitly with CREATE STATISTICS or
   custom statistics added by an extension. Therefore, it may be useful to
   run ANALYZE after restoring from a dump file to ensure optimal
   performance; see Section 24.1.3 and Section 24.1.6 for more
   information.

   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 9.2 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. Use of the --quote-all-identifiers
   option is recommended in cross-version cases, as it can prevent
   problems arising from varying reserved-word lists in different
   PostgreSQL versions.

   When dumping logical replication subscriptions, pg_dump will generate
   CREATE SUBSCRIPTION commands that use the connect = false 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. If
   users intend to copy initial data during refresh they must create the
   slot with two_phase = false. After the initial sync, the two_phase
   option will be automatically enabled by the subscriber if the
   subscription had been originally created with two_phase = true option.

   It is generally recommended to use the -X (--no-psqlrc) option when
   restoring a database from a plain-text pg_dump script to ensure a clean
   restore process and prevent potential conflicts with non-default psql
   configurations.

Examples

   To dump a database called mydb into an SQL-script file:
$ pg_dump mydb > db.sql

   To reload such a script into a (freshly created) database named newdb:
$ psql -X -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 dump a database into a directory-format archive in parallel with 5
   worker jobs:
$ pg_dump -Fd mydb -j 5 -f dumpdir

   To reload an archive file into a (freshly created) database named
   newdb:
$ pg_restore -d newdb db.dump

   To reload an archive file into the same database it was dumped from,
   discarding the current contents of that database:
$ pg_restore -d postgres --clean --create 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

   To dump all tables whose names start with mytable, except for table
   mytable2, specify a filter file filter.txt like:
include table mytable*
exclude table mytable2

$ pg_dump --filter=filter.txt mydb > db.sql

See Also

   pg_dumpall, pg_restore, psql