IBM DB2 Federated Services allow for the creation of federated database systems where multiple database instances can be configured as federated servers. These servers can manage requests from end-users and client applications, distributing parts of these requests to different data sources for processing. One of the key features of federated servers is their ability to perform pushdown operations, where operations are processed remotely by the data sources. This is enabled through the use of DRDA communication protocols and native client access to various data sources, like Sybase or Microsoft SQL Server, enhancing interoperability and flexibility in data management across diverse environments.

If you have troubles with performance of SQL operations using federated databases, this new and undocumented Db2 environment variable may help: