CREATE SERVER

Function

CREATE SERVER defines a new foreign server.

Syntax

CreateServer ::= CREATE SERVER server_name
    FOREIGN DATA WRAPPER fdw_name
    OPTIONS ( { option_name ' value ' } [, ...] ) ;

Parameter Description

• server_name

  Specifies the server name.

  Value range: a string containing no more than 63 characters

• fdw_name

  Specifies the name of the foreign data wrapper.

  Value range: oracle_fdw, mysql_fdw, postgres_fdw, mot_fdw, and file_fdw

• OPTIONS ( { option_name ' value ' } [, …] )

  Specifies options for the server. These options typically define the connection details of the server, but the actual names and values depend on the foreign data wrapper of the server.

  • Options supported by oracle_fdw are as follows:

    • dbserver

      Connection string of the remote Oracle database.

    • isolation_level (default value: serializable)

      Oracle database transaction isolation level.

      Value range: serializable, read_committed, and read_only

  • Options supported by mysql_fdw are as follows:

    • host (default value: 127.0.0.1)

      IP address of the MySQL server or MariaDB.

    • port (default value: 3306)

      Listening port number of the MySQL server or MariaDB.

  • The options supported by postgres_fdw are the same as those supported by libpq. For details, see Link Parameters. Note that the following options cannot be set:

    • user and password

      The user name and password are specified when the user mapping is created.

    • client_encoding

      The encoding mode of the local server is automatically obtained and set.

    • application_name

      This option is always set to postgres_fdw.

  • Specifies the parameters for the foreign server. The detailed parameter description is as follows:

    • encrypt

      Specifies whether data is encrypted. This parameter is available only when type is OBS. The default value is on.

      Value range:

      • on indicates that data is encrypted and HTTPS is used for communication.
      • off indicates that data is not encrypted and HTTP is used for communication.

    • access_key

      Specifies the access key (AK) (obtained by users from the OBS console) used for the OBS access protocol. When you create a foreign table, the AK value is encrypted and saved to the metadata table of the database. This parameter is available only when type is set to OBS.

    • secret_access_key

      Specifies the secret key (SK) value (obtained by users from the OBS console) used for the OBS access protocol. When you create a foreign table, the SK value is encrypted and saved to the metadata table of the database. This parameter is available only when type is set to OBS.

In addition to the connection parameters supported by libpq, the following options are provided:

• use_remote_estimate

  Controls whether postgres_fdw issues the EXPLAIN command to obtain the estimated run time. The default value is false.

• fdw_startup_cost

  Estimates the startup time required for a foreign table scan, including the time to establish a connection, analyzes the request at the remote server, and generates a plan. The default value is 100.

• fdw_typle_cost

  Specifies the additional consumption when each tuple is scanned on a remote server. The value specifies the extra consumption of data transmission between servers. The default value is 0.01.

Examples

Create a server.

MogDB=# create server my_server foreign data wrapper log_fdw;
CREATE SERVER

Helpful Links

ALTER SERVER and DROP SERVER