'\" t
.\"     Title: clusterdb
.\"    Author: The PostgreSQL Global Development Group
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 2024
.\"    Manual: PostgreSQL 16.3 Documentation
.\"    Source: PostgreSQL 16.3
.\"  Language: English
.\"
.TH "CLUSTERDB" "1" "2024" "PostgreSQL 16.3" "PostgreSQL 16.3 Documentation"
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.SH "NAME"
clusterdb \- cluster a PostgreSQL database
.SH "SYNOPSIS"
.HP \w'\fBclusterdb\fR\ 'u
\fBclusterdb\fR [\fIconnection\-option\fR...] [\fB\-\-verbose\fR | \fB\-v\fR] [\ \fB\-\-table\fR\ |\ \fB\-t\fR\ \fItable\fR\ ]...  [\fIdbname\fR]
.HP \w'\fBclusterdb\fR\ 'u
\fBclusterdb\fR [\fIconnection\-option\fR...] [\fB\-\-verbose\fR | \fB\-v\fR] \fB\-\-all\fR | \fB\-a\fR 
.SH "DESCRIPTION"
.PP
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\&.
.PP
clusterdb
is a wrapper around the SQL command
\fBCLUSTER\fR(7)\&. There is no effective difference between clustering databases via this utility and via other methods for accessing the server\&.
.SH "OPTIONS"
.PP
clusterdb
accepts the following command\-line arguments:
.PP
\fB\-a\fR
.br
\fB\-\-all\fR
.RS 4
Cluster all databases\&.
.RE
.PP
\fB[\-d]\fR\fB \fR\fB\fIdbname\fR\fR
.br
\fB[\-\-dbname=]\fR\fB\fIdbname\fR\fR
.RS 4
Specifies the name of the database to be clustered, when
\fB\-a\fR/\fB\-\-all\fR
is not used\&. If this is not specified, the database name is read from the environment variable
\fBPGDATABASE\fR\&. If that is not set, the user name specified for the connection is used\&. The
\fIdbname\fR
can be a
connection string\&. If so, connection string parameters will override any conflicting command line options\&.
.RE
.PP
\fB\-e\fR
.br
\fB\-\-echo\fR
.RS 4
Echo the commands that
clusterdb
generates and sends to the server\&.
.RE
.PP
\fB\-q\fR
.br
\fB\-\-quiet\fR
.RS 4
Do not display progress messages\&.
.RE
.PP
\fB\-t \fR\fB\fItable\fR\fR
.br
\fB\-\-table=\fR\fB\fItable\fR\fR
.RS 4
Cluster
\fItable\fR
only\&. Multiple tables can be clustered by writing multiple
\fB\-t\fR
switches\&.
.RE
.PP
\fB\-v\fR
.br
\fB\-\-verbose\fR
.RS 4
Print detailed information during processing\&.
.RE
.PP
\fB\-V\fR
.br
\fB\-\-version\fR
.RS 4
Print the
clusterdb
version and exit\&.
.RE
.PP
\fB\-?\fR
.br
\fB\-\-help\fR
.RS 4
Show help about
clusterdb
command line arguments, and exit\&.
.RE
.PP
clusterdb
also accepts the following command\-line arguments for connection parameters:
.PP
\fB\-h \fR\fB\fIhost\fR\fR
.br
\fB\-\-host=\fR\fB\fIhost\fR\fR
.RS 4
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\&.
.RE
.PP
\fB\-p \fR\fB\fIport\fR\fR
.br
\fB\-\-port=\fR\fB\fIport\fR\fR
.RS 4
Specifies the TCP port or local Unix domain socket file extension on which the server is listening for connections\&.
.RE
.PP
\fB\-U \fR\fB\fIusername\fR\fR
.br
\fB\-\-username=\fR\fB\fIusername\fR\fR
.RS 4
User name to connect as\&.
.RE
.PP
\fB\-w\fR
.br
\fB\-\-no\-password\fR
.RS 4
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\&.
.RE
.PP
\fB\-W\fR
.br
\fB\-\-password\fR
.RS 4
Force
clusterdb
to prompt for a password before connecting to a database\&.
.sp
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
\fB\-W\fR
to avoid the extra connection attempt\&.
.RE
.PP
\fB\-\-maintenance\-db=\fR\fB\fIdbname\fR\fR
.RS 4
Specifies the name of the database to connect to to discover which databases should be clustered, when
\fB\-a\fR/\fB\-\-all\fR
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\&.
.RE
.SH "ENVIRONMENT"
.PP
\fBPGDATABASE\fR
.br
\fBPGHOST\fR
.br
\fBPGPORT\fR
.br
\fBPGUSER\fR
.RS 4
Default connection parameters
.RE
.PP
\fBPG_COLOR\fR
.RS 4
Specifies whether to use color in diagnostic messages\&. Possible values are
always,
auto
and
never\&.
.RE
.PP
This utility, like most other
PostgreSQL
utilities, also uses the environment variables supported by
libpq
(see
Section\ \&34.15)\&.
.SH "DIAGNOSTICS"
.PP
In case of difficulty, see
\fBCLUSTER\fR(7)
and
\fBpsql\fR(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\&.
.SH "EXAMPLES"
.PP
To cluster the database
test:
.sp
.if n \{\
.RS 4
.\}
.nf
$ \fBclusterdb test\fR
.fi
.if n \{\
.RE
.\}
.PP
To cluster a single table
foo
in a database named
xyzzy:
.sp
.if n \{\
.RS 4
.\}
.nf
$ \fBclusterdb \-\-table=foo xyzzy\fR
.fi
.if n \{\
.RE
.\}
.SH "SEE ALSO"
\fBCLUSTER\fR(7)