Federated failure modes
Teiid provides the capability to obtain partial results in the event of data source unavailability or failure. This is especially useful when unioning information from multiple sources, or when doing a left outer join, where you are appending columns to a master record, but still want the record if the extra information is not available.
A source is considered to be unavailable if the connection factory that is associated with the source generates an exception in response to a query. The exception will be propagated to the query processor, where it will become a warning on the statement. For more information about partial results and SQLWarning objects, see Partial Results Mode in the Client Developer’s Guide.