International Business Machines Corporation

Glenn P Steffler

Ian R Finlay

Sunil Sarin

Robert Neugebauer

Dirk Alexander Seelemann, Ii

Mohammad Wasif Khan

Thomas P Boldt

Embodiments are disclosed for a method. The method includes receiving a plurality of local deltas for a query execution against a corresponding plurality of data sources hosted by a corresponding plurality of distributed nodes of a dynamic distributed network. The method also includes generating a combined delta by combining the local deltas. Additionally, the method includes generating a determined delta result by performing additional processing on the combined delta. Further, the method includes providing the determined delta for one of the distributed nodes.

Generating a global delta in distributed databases

Embodiments are disclosed for a method. The method includes parsing a distributed database query into component queries corresponding to distributed nodes. The method also includes matching component queries to central cache to determine whether the component queries can be satisfied. This matching generates matched and unmatched component queries. The method further includes transforming the matched component query to a cache query and local delta query for a first node. Additionally, the method includes executing the cache query to generate a cache result. Also, the method includes providing the local delta query for the first node to generate a local delta. Further, the method includes providing the unmatched component query for a second node to generate a remote result. The method also includes generating a global delta based on the local delta. The method additionally includes generating a result by combining the cache result, local delta, and remote result.

Querying distributed databases

Consistency of replicated data copies with statement-based replication is provided without requiring transaction serializability. At a subordinate replication node, a transaction start message, replicated data modification statements, and a transaction commit message are received for a next committed transaction from a master replication node, wherein the transaction start message carries a master transaction identifier, an invisibility list consisting of identifiers of other master transactions that had started and not yet committed when this master transaction started, and an earliest invisible master transaction identifier. The master transaction identifier, invisibility list, and earliest invisible transaction identifier are mapped to subordinate transaction identifiers to preserve an order of transaction identifiers from the master replication node. A subordinate transaction is started with the mapped subordinate transaction identifier and with an invisibility list consisting of the mapped subordinate transaction identifiers for the master invisibility list for execution of the received data modification statements.

Growing community of inventors

Markham, Canada

Glenn P Steffler