clusterdb(1) PostgreSQL 18.6 Documentation clusterdb(1)
NAME
clusterdb - cluster a PostgreSQL database
SYNOPSIS
clusterdb [connection-option...] [option...] [ --table | -t table ]...
[dbname | -a | --all]
DESCRIPTION
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.
OPTIONS
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
When the -a/--all is used, connect to this database to gather the
list of databases to cluster. 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.
ENVIRONMENT
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 32.15).
DIAGNOSTICS
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.
EXAMPLES
To cluster the database test:
$ clusterdb test
To cluster a single table foo in a database named xyzzy:
$ clusterdb --table=foo xyzzy
SEE ALSO
CLUSTER(7)
PostgreSQL 18.6 2026 clusterdb(1)
postgresql 18.6_0 - Generated Wed Aug 26 13:59:18 CDT 2026