CREATE SERVER
Function
Defines a new foreign server.
Syntax
CREATE SERVER server_name
[ TYPE ' server_type ' ]
[ VERSION ' server_version ' ]
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
server_type
Optional server type, which may be useful for foreign data wrappers.
server_version
Optional server version, which may be useful for foreign data wrappers.
fdw_name
Specifies the name of the foreign data wrapper.
Value range: dist_fdw, hdfs_fdw, log_fdw, file_fdw, mot_fdw, oracle_fdw, mysql_fdw, postgres_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
The 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 Connection Character Strings. 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.
NOTE:
In the Lite edition, openGauss does not support obs_server in the CREATE SERVER syntax.
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. This value usually contains the time taken to establish a connection, analyze the request at the remote end, and generate 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.
openGauss=* create server my_server foreign data wrapper log_fdw;
CREATE SERVER