Patent ID: 8538985

Claim:
A computer-implemented method for processing a federated query in a federated database system, wherein a database table is physically distributed across a first designated source server and a second designated source server, the method comprising: receiving a federated query at a federated database server; generating a federated query execution plan at the federated database server, based on the received federated query, the federated query execution plan defining one or more source servers of the federated database and a unique subquery to be executed on each of the defined one or more source servers; distributing each unique subquery to a defined source server, in accordance with the federated query execution plan; executing each unique subquery asynchronously by the defined source server; connecting a source server to a first designated source server among the one or more source servers, using a first message queue, and without the connection passing through the federated database server; connecting a source server to a second designated source server among the one or more source servers, using a second message queue, and without the connection passing through the federated database server; passing, based on parameters specified in the federated query, a first subset of the subquery results to the first designated source server, using the first message queue, and a second subset of the subquery results to the second designated source server, using the second message queue; joining and aggregating the first subset of the subquery results by the first designated source server into a first final query result; joining and aggregating the second subset of the subquery results by the second designated source server into a second final query result; returning the first and second final query results to the federated database server; and combining the first and second final query results at the federated database server.