Features of the Hadoop Foreign Data Wrapper v2.0.7
The key features of the Hadoop Foreign Data Wrapper are listed below:
Hadoop Foreign Data Wrappper allows the push-down of
WHERE clause to the foreign server for execution. This feature optimizes remote queries to reduce the number of rows transferred from foreign servers.
Hadoop Foreign Data Wrapper supports column push-down. As a result, the query brings back only those columns that are a part of the select target list.
Hadoop Foreign Data Wrappper allows the cleanup of foreign tables in a single operation using
DROP EXTENSION command. This feature is specifically useful when a foreign table is set for a temporary purpose, as in case of data migration. The syntax is:
DROP EXTENSION hdfs_fdw CASCADE;
For more information, see DROP EXTENSION.