postgres_fdw extension

The postgres_fdw module provides the foreign-data wrapper postgres_fdw, which can be used to access data stored in external PostgreSQL or YugabyteDB servers.

In v2026.1.2 and later, the extension is installed into pg_catalog during cluster initialization (and on upgrade) so cluster-wide database views can be created by default. CREATE EXTENSION IF NOT EXISTS postgres_fdw is harmless if you run it; if the extension is already installed, it reports NOTICE: extension "postgres_fdw" already exists, skipping:

CREATE EXTENSION IF NOT EXISTS postgres_fdw;

To connect to a remote PostgreSQL database, create a foreign server object. Specify the connection information (except the username and password) using the OPTIONS clause:

CREATE SERVER my_server FOREIGN DATA WRAPPER postgres_fdw
    OPTIONS (host 'host_ip', dbname 'external_db', port 'port_number');

For a remote YugabyteDB cluster, include server_type when you create the server.

Specify the username and password using CREATE USER MAPPING:

CREATE USER MAPPING FOR mylocaluser SERVER my_server OPTIONS (user 'remote_user', password 'password');

You can now create foreign tables using CREATE FOREIGN TABLE and IMPORT FOREIGN SCHEMA:

CREATE FOREIGN TABLE table_name (colname1 int, colname2 int) SERVER my_server OPTIONS (schema_name 'schema', table_name 'table');
IMPORT FOREIGN SCHEMA foreign_schema_name FROM SERVER my_server INTO local_schema_name;

You can execute SELECT statements on the foreign tables to access the data in the corresponding remote tables.

server_type option

server_type is a YugabyteDB addition to the server options postgres_fdw accepts. It tells the wrapper what kind of server is behind the foreign tables, which decides how rows are identified and, for one value, how the query runs.

Set the option when you create the server.

For example, create a server for a remote YugabyteDB cluster:

CREATE SERVER my_server FOREIGN DATA WRAPPER postgres_fdw
    OPTIONS (server_type 'yugabyteDB', host 'host_ip', dbname 'external_db', port 'port_number');

The value is case-insensitive. If you don't specify a server, the system defaults to postgreSQL and reports the following:

NOTICE:  no server_type specified. Defaulting to PostgreSQL.
HINT:  Use "ALTER SERVER ... OPTIONS (ADD server_type '<type>')" to explicitly set server_type.

federatedYugabyteDB doesn't take host, dbname, or port, and doesn't need CREATE USER MAPPING because the target nodes come from the cluster's own tablet server list and each node is reached over an internal connection. YugabyteDB creates one such server, yb_global_views_server, and uses it for cluster-wide database views. You don't need to create this server yourself; it is equivalent to:

CREATE SERVER yb_global_views_server FOREIGN DATA WRAPPER postgres_fdw
    OPTIONS (server_type 'federatedYugabyteDB');