# CLUSTERDB - cluster a PostgreSQL database - man - [phpMan]

> **TLDR:** Cluster (reorganize) a PostgreSQL database.
>
- Cluster a specific database:
  `clusterdb {{database_name}}`
- Cluster all databases:
  `clusterdb {{-a|--all}}`
- Cluster a specific table in a database:
  `clusterdb {{-t|--table}} {{table_name}} {{database_name}}`

*Source: tldr-pages*

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[_CLUSTERDB_(1)](https://www.chedong.com/phpMan.php/man/CLUSTERDB/1/markdown)                       PostgreSQL 16.14 Documentation                       [_CLUSTERDB_(1)](https://www.chedong.com/phpMan.php/man/CLUSTERDB/1/markdown)

## NAME
       clusterdb - cluster a PostgreSQL database

## SYNOPSIS


       **clusterdb **[_connection-option_...] [**--verbose **| **-v**] [ **--table **| **-t _**table_ ]...  [_dbname_]

       **clusterdb **[_connection-option_...] [**--verbose **| **-v**] **--all **| **-a**

## 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)](https://www.chedong.com/phpMan.php/man/CLUSTER/7/markdown). 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_
           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_
           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_
           Specifies the TCP port or local Unix domain socket file extension on which the server is
           listening for connections.

### -U _
       **--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 34.15).

## DIAGNOSTICS
       In case of difficulty, see [**CLUSTER**(7)](https://www.chedong.com/phpMan.php/man/CLUSTER/7/markdown) and [**psql**(1)](https://www.chedong.com/phpMan.php/man/psql/1/markdown) 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)](https://www.chedong.com/phpMan.php/man/CLUSTER/7/markdown)

PostgreSQL 16.14                                2026                                    [_CLUSTERDB_(1)](https://www.chedong.com/phpMan.php/man/CLUSTERDB/1/markdown)