Remote Join

The remote join problem regards the issues when one tries to join two remote DBMSs (Database Management Systems).

Remote join is a method capable of executing a join across two DBMSs (Database Management Systems). This may be done by shipping the data directly to the other DBMS (Database Management System) or to the HDBMS (Hierarchical Database Management System) which in turn coordinates with the other DBMS (Database Management Systems) to compute the join. For each remote join, a cost function is associated and the cost of the complete execution is computed in the traditional manner.

One solution to the remote join problem is to create a join view at the remote database, create a local synonym for this view, and then retrieve through this view. Distributed joins have caused performance problems throughout the history of distributed database support.