CLUSTERDB(1) PostgreSQL 16.3 Documentation CLUSTERDB(1)

clusterdb - cluster a PostgreSQL database

clusterdb [connection-option...] [--verbose | -v] [ --table | -t table ]... [dbname]

clusterdb [connection-option...] [--verbose | -v] --all | -a

clusterdb is a utility for reclustering tables in a PostgreSQL database. It finds tables that have previously been clustered, and clusters them again on the same index that was last used. Tables that have never been clustered are not affected.

clusterdb is a wrapper around the SQL command CLUSTER(7). There is no effective difference between clustering databases via this utility and via other methods for accessing the server.

clusterdb accepts the following command-line arguments:

-a
--all

Cluster all databases.

[-d] dbname
[--dbname=]dbname

Specifies the name of the database to be clustered, when -a/--all is not used. If this is not specified, the database name is read from the environment variable PGDATABASE. If that is not set, the user name specified for the connection is used. The dbname can be a connection string. If so, connection string parameters will override any conflicting command line options.

-e
--echo

Echo the commands that clusterdb generates and sends to the server.

-q
--quiet

Do not display progress messages.

-t table
--table=table

Cluster table only. Multiple tables can be clustered by writing multiple -t switches.

-v
--verbose

Print detailed information during processing.

-V
--version

Print the clusterdb version and exit.

-?
--help

Show help about clusterdb command line arguments, and exit.

clusterdb also accepts the following command-line arguments for 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.

-p port
--port=port

Specifies the TCP port or local Unix domain socket file extension on which the server is listening for connections.

-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 clusterdb to prompt for a password before connecting to a database.

This option is never essential, since clusterdb will automatically prompt for a password if the server demands password authentication. However, clusterdb 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.

--maintenance-db=dbname

Specifies the name of the database to connect to to discover which databases should be clustered, when -a/--all is used. If not specified, the postgres database will be used, or if that does not exist, template1 will be used. This can be a connection string. If so, connection string parameters will override any conflicting command line options. Also, connection string parameters other than the database name itself will be re-used when connecting to other databases.

PGDATABASE
PGHOST
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 34.15).

In case of difficulty, see CLUSTER(7) and psql(1) for discussions of potential problems and error messages. The database server must be running at the targeted host. Also, any default connection settings and environment variables used by the libpq front-end library will apply.

To cluster the database test:

$ clusterdb test

To cluster a single table foo in a database named xyzzy:

$ clusterdb --table=foo xyzzy

CLUSTER(7)

2024 PostgreSQL 16.3