postgres_fdw v6.27.4

The postgres_fdw module is a foreign data wrapper (FDW) that you can use to access data stored in a remote PostgreSQL or WarehousePG.

The WarehousePG postgres_fdw module is a modified version of the PostgreSQL postgres_fdw module. The module behaves as described in the PostgreSQL postgres_fdw documentation when you use it to access a remote PostgreSQL database.

Note There are some restrictions and limitations when you use this foreign data wrapper module to access WarehousePG, described below.

Installing and Registering the Module

The postgres_fdw module is installed when you install WarehousePG. Before you can use the foreign data wrapper, you must register the postgres_fdw extension in each database in which you want to use the foreign data wrapper. Refer to Installing Extensions for more information.

WarehousePG Limitations

When you use the foreign data wrapper to access WarehousePG, postgres_fdw has the following limitations:

• The ctid is not guaranteed to uniquely identify the physical location of a row within its table. For example, the following statements may return incorrect results when the foreign table references a WarehousePG table:

  → WrapCopy

  INSERT INTO rem1(f2) VALUES ('test') RETURNING ctid;
  SELECT * FROM ft1, t1 WHERE t1.ctid = '(0,2)'; 

• postgres_fdw does not support local or remote triggers when you use it to access a foreign table that references a WarehousePG table.

• UPDATE or DELETE operations on a foreign table that references a WarehousePG table are not guaranteed to work correctly.

Additional Module Documentation

Refer to the postgres_fdw PostgreSQL documentation for detailed information about this module.