|PostgreSQL Reference Manual - Volume 1 - SQL Language Reference|
by The PostgreSQL Global Development Group
Paperback (6"x9"), 716 pages
RRP £32.00 ($49.95)
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pg_dumpall -- extract a PostgreSQL database cluster into a script file
pg_dumpall is a utility for writing out
(“dumping”) all PostgreSQL databases
of a cluster into one script file. The script file contains
SQL commands that can be used as input to
psql to restore the databases. It does this by
pg_dump for each database in a cluster.
pg_dumpall also dumps global objects
that are common to all databases.
(pg_dump does not save these objects.)
This currently includes information about database users and
groups, and access permissions that apply to databases as a whole.
Since pg_dumpall reads tables from all databases you will most likely have to connect as a database superuser in order to produce a complete dump. Also you will need superuser privileges to execute the saved script in order to be allowed to add users and groups, and to create databases.
The SQL script will be written to the standard output. Shell operators should be used to redirect it into a file.
pg_dumpall needs to connect several times to the PostgreSQL server (once per database). If you use password authentication it is likely to ask for a password each time. It is convenient to have a ‘~/.pgpass’ file in such cases. See Volume 2: The Password File for more information.
The following command-line options control the content and format of the output.
- Dump only the data, not the schema (data definitions).
Include SQL commands to clean (drop) databases before
DROPcommands for roles and tablespaces are added as well.
Dump data as
INSERTcommands (rather than
COPY). This will make restoration very slow; it is mainly useful for making dumps that can be loaded into non-PostgreSQL databases. Note that the restore may fail altogether if you have rearranged column order. The
-Doption is safer, though even slower.
Dump data as
INSERTcommands 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.
- Dump only global objects (roles and tablespaces), no databases.
- Ignore version mismatch between pg_dumpall and the database server. pg_dumpall can handle databases from previous releases of PostgreSQL, but very old versions are not supported anymore (currently prior to 7.0). Use this option if you need to override the version check (and if pg_dumpall then fails, don't say you weren't warned).
- 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.
Do not output commands to set
ownership of objects to match the original database.
By default, pg_dumpall issues
SET SESSION AUTHORIZATIONstatements to set ownership of created schema elements. 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
- Dump only the object definitions (schema), not data.
Specify the superuser user name to use when disabling triggers.
This is only relevant if
--disable-triggersis used. (Usually, it's better to leave this out, and instead start the resulting script as superuser.)
- Specifies verbose mode. This will cause pg_dumpall to output start/stop times to the dump file, and progress messages to standard error. It will also enable verbose output in pg_dump.
- Prevent dumping of access privileges (grant/revoke commands).
- This option disables the use of dollar quoting for function bodies, and forces them to be quoted using SQL standard string syntax.
This option is only relevant when creating a data-only dump.
It instructs pg_dumpall 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-triggersmust 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.
SET SESSION AUTHORIZATIONcommands instead of
ALTER OWNERcommands to determine object ownership. This makes the dump more standards compatible, but depending on the history of the objects in the dump, may not restore properly.
The following command-line options control the database connection parameters.
- -h host
Specifies the host name of the machine on which the database
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
PGHOSTenvironment variable, if set, else a Unix domain socket connection is attempted.
- -p port
Specifies the TCP port or local Unix domain socket file
extension on which the server is listening for connections.
Defaults to the
PGPORTenvironment variable, if set, or a compiled-in default.
- -U username
- Connect as the given user.
- Force a password prompt. This should happen automatically if the server requires password authentication.
- Default connection parameters
Since pg_dumpall calls pg_dump internally, some diagnostic messages will refer to pg_dump.
Once restored, it is wise to run
ANALYZE on each
database so the optimizer has useful statistics. You
can also run
vacuumdb -a -z to analyze all
pg_dumpall requires all needed tablespace directories to exist before the restore or database creation will fail for databases in non-default locations.
To dump all databases:
$ pg_dumpall > db.out
To reload this database use, for example:
$ psql -f db.out postgres
(It is not important to which database you connect here since the script file created by pg_dumpall will contain the appropriate commands to create and connect to the saved databases.)
|ISBN 0954612027||PostgreSQL Reference Manual - Volume 1 - SQL Language Reference||See the print edition|