Updating an oracle view
The Oracle query that oracle_fdw constructs will contain a WHERE clause corresponding to these filter criteria whenever such a condition can safely be translated to Oracle SQL.
This feature, also known as , can greatly reduce the number of rows retrieved from Oracle and may enable Oracle's optimizer to choose a good plan for accessing the required tables.
From Postgre SQL 9.6 on, oracle_fdw can push down joins to the Oracle server, that is, a join between two foreign tables will lead to a single Oracle query that performs the join on the Oracle side.
There are some restrictions when this can happen: It is important that table statistics for both foreign tables have been collected with ANALYZE for Postgre SQL to determine the best join strategy.
Create a new foreign data wrapper if you want the options to be persistent.Special thanks to Christian Ullrich for ongoing help with Windows. More detailed information will be provided in the sections Options and Usage.You should also read the [Postgre SQL documentation on foreign data] (https:// and the commands referenced there.We want to access a table defined like this: pgdb=# CREATE EXTENSION oracle_fdw; pgdb=# CREATE SERVER oradb FOREIGN DATA WRAPPER oracle_fdw OPTIONS (dbserver '//dbserver.mydomain.com:1521/ORADB'); pgdb=# GRANT USAGE ON FOREIGN SERVER oradb TO pguser; .Normally that's all you need, and you can proceed to define foreign servers.