Data source collating sequence

The collating sequence that you choose might affect performance of the federated database. You can use the COLLATING_SEQUENCE server option to indicate if a data source collating sequence matches the local federated database collating sequence.

The federated server can push down order-dependent processing that involves character data to the data source, if the COLLATING_SEQUENCE server option indicates that the collating sequence of the data source and the federated database match. If a data source collating sequence does not match the federated database collating sequence, the optimizer considers data that is retrieved from this data source unordered. The federated database will retrieve the relevant data and perform all order-dependent processing on character data locally, which can slow down the query and affect performance.