PostgreSQL 7.3.4 Documentation
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# clusterdb

## Name

clusterdb -- cluster a PostgreSQL database

## Synopsis

`clusterdb` [connection-options...] [--table | -t table ] [dbname]
`clusterdb` [connection-options...] [--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 touched.

clusterdb is a shell script wrapper around the backend command CLUSTER via the PostgreSQL interactive terminal psql. There is no effective difference between clustering databases via this or other methods. psql must be found by the script and a database server must be running at the targeted host. Also, any default settings and environment variables available to psql and the libpq front-end library do apply.

clusterdb might need to connect several times to the PostgreSQL server, asking for a password each time. It is convenient to have a `$HOME/.pgpass` file in such cases.

## 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. If this is not specified and -a (or --all) is not used, the database name is read from the environment variable `PGDATABASE`. If that is not set, the user name specified for the connection is used.

-e
--echo

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

-q
--quiet

  Do not display a response.

-t table
--table table

  Clusters table only.

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 host begins with a slash, it is used as the directory for the Unix domain socket.

-p port
--port port

  Specifies the Internet TCP/IP 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
--password

  Force password prompt.

## Diagnostics

`CLUSTER`

  Everything went well.

`clusterdb: Cluster failed.`

  Something went wrong. clusterdb is only a wrapper script. See CLUSTER and psql for a detailed discussion of error messages and potential problems. Note that this message may appear once per table to be clustered.

## Environment

`PGDATABASE`
`PGHOST`
`PGPORT`
`PGUSER`

  Default connection parameters.

## 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

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