clusterdb — cluster a LightDB 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 LightDB 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. 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--allCluster 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 LTDATABASE. 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--echoEcho the commands that clusterdb generates and sends to the server.
-q--quietDo not display progress messages.
-t table--table=table
Cluster table only.
Multiple tables can be clustered by writing multiple
-t switches.
-v--verbosePrint detailed information during processing.
-V--versionPrint the clusterdb version and exit.
-?--helpShow help about clusterdb command line arguments, and exit.
clusterdb also accepts the following command-line arguments for connection parameters:
-h host--host=hostSpecifies 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=portSpecifies the TCP port or local Unix domain socket file extension on which the server is listening for connections.
-U username--username=usernameUser 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--passwordForce 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.
LTDATABASELTHOSTLTPORTLTUSERDefault connection parameters
LT_COLOR
Specifies whether to use color in diagnostic messages. Possible values
are always, auto and
never.
This utility, like most other LightDB utilities, also uses the environment variables supported by libpq (see Section 32.14).
In case of difficulty, see CLUSTER and ltsql 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