Defines a new foreign server.

Synopsis

CREATE SERVER <server_name> [ TYPE '<server_type>' ] [ VERSION '<server_version>' ]
    FOREIGN DATA WRAPPER <fdw_name>
    [ OPTIONS ( [ mpp_execute { 'master' | 'any' | 'all segments' } [, ] ]
                [ num_segments '<num>' [, ] ]
                [ <option> '<value>' [, ... ]] ) ]

Description

CREATE SERVER defines a new foreign server. The user who defines the server becomes its owner.

A foreign server typically encapsulates connection information that a foreign-data wrapper uses to access an external data source. Additional user-specific connection information may be specified by means of user mappings.

Creating a server requires the USAGE privilege on the foreign-data wrapper specified.

Parameters

server_name
The name of the foreign server to create. The server name must be unique within the database.
server_type
Optional server type, potentially useful to foreign-data wrappers.
server_version
Optional server version, potentially useful to foreign-data wrappers.
fdw_name
Name of the foreign-data wrapper that manages the server.
OPTIONS ( option 'value' [, ... ] )
The options for the new foreign server. The options typically define the connection details of the server, but the actual names and values are dependent upon the server's foreign-data wrapper.
mpp_execute { 'master' | 'any' | 'all segments' }

A Greenplum Database-specific option that identifies the host from which the foreign-data wrapper reads or writes data:

  • master (the default)—Read or write data from the master host.
  • any—Read data from either the master host or any one segment, depending on which path costs less.
  • all segments—Read or write data from all segments. To support this option value, the foreign-data wrapper should have a policy that matches the segments to data.

    Note: Greenplum Database supports parallel writes to foreign tables only when you set mpp_execute 'all segments'.

Support for the foreign server mpp_execute option, and the specific modes, is foreign-data wrapper-specific.

The mpp_execute option can be specified in multiple commands: CREATE FOREIGN TABLE, CREATE SERVER, and CREATE FOREIGN DATA WRAPPER. The foreign table setting takes precedence over the foreign server setting, followed by the foreign-data wrapper setting.

num_segments 'num'

When mpp_execute is set to 'all segments', the Greenplum Database-specific num_segments option identifies the number of query executors that Greenplum Database spawns on the source Greenplum Database cluster. If you do not provide a value, num defaults to the number of segments in the source cluster.

Support for the foreign server num_segments option is foreign-data wrapper-specific.

Notes

When using the dblink module (see dblink), you can use the foreign server name as an argument of the dblink_connect() function to provide the connection parameters. You must have the USAGE privilege on the foreign server to use it in this manner.

Examples

Create a foreign server named myserver that uses the foreign-data wrapper named pgsql and includes connection options:

CREATE SERVER myserver FOREIGN DATA WRAPPER pgsql 
    OPTIONS (host 'foo', dbname 'foodb', port '5432');

Compatibility

CREATE SERVER conforms to ISO/IEC 9075-9 (SQL/MED).

See Also

ALTER SERVER, DROP SERVER, CREATE FOREIGN DATA WRAPPER, CREATE USER MAPPING

Parent topic: SQL Commands

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