CREATE SERVER

Defines a new foreign server.

Synopsis

CREATE SERVER [ IF NOT EXISTS ] <server_name> [ TYPE '<server_type>' ] [ VERSION '<server_version>' ]
    FOREIGN DATA WRAPPER <fdw_name>
    [ OPTIONS ( [ mpp_execute { 'coordinator' | '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

IF NOT EXISTS

Do not throw an error if a server with the same name already exists. Greenplum Database issues a notice in this case. Note that there is no guarantee that the existing server is anything like the one that would have been created.

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 { 'coordinator' | 'any' | 'all segments' }

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

coordinator (the default)—Read or write data from the coordinator host.
any—Read data from either the coordinator 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 a foreign-data wrapper named gpfdw1 and includes connection options:

CREATE SERVER myserver FOREIGN DATA WRAPPER gpfdw1 
    OPTIONS (host 'foo', dbname 'foodb', port '5432');

Compatibility

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