Twin-Transaction ModelTwin-Transaction Model

Replicate the process of processing Replicate the process of processing transactions along with replicating a data itemtransactions along with replicating a data item

Transaction Transaction TT will be mirrored to generate twin- will be mirrored to generate twin-transactions {transactions {TTxx,T,Too}}

TTxx will execute on replicated data item will execute on replicated data item maintained by host receiving the transaction.maintained by host receiving the transaction.

Disconnected OperationDisconnected Operation

Each transaction’s probability of conflict (Each transaction’s probability of conflict () is ) is calculated usingcalculated using = F(HD= F(HDkk, HD, HDii))

A Function of patterns of previous conflictsA Function of patterns of previous conflicts HDHDkk is a set of data items updated by transaction is a set of data items updated by transaction HDHDii is a set of data items that have a probability of is a set of data items that have a probability of

update or read of more than a defined threshold on update or read of more than a defined threshold on that DM.that DM.

Any transaction having a conflict probability Any transaction having a conflict probability greater than a threshold value is not allowed to greater than a threshold value is not allowed to execute.execute.

Implementation StateImplementation State

Implemented under Windows NT operating Implemented under Windows NT operating system and consists of following parts:system and consists of following parts: Twin-Transaction Manager (TTMG)Twin-Transaction Manager (TTMG) Twin-Transaction Agent (TTA)Twin-Transaction Agent (TTA) Transaction Agent (TA)Transaction Agent (TA) Conflict and Pattern Recognition Agent (CPRA)Conflict and Pattern Recognition Agent (CPRA)

TTMG initiates the transaction and TTA TTMG initiates the transaction and TTA handles the transaction operations via TA handles the transaction operations via TA (for a data store). CRPA calculates the (for a data store). CRPA calculates the probability of success for a running probability of success for a running transaction.transaction.

Twin-Transaction software system Twin-Transaction software system “Contact-Manager with Mobile Directory” is “Contact-Manager with Mobile Directory” is written.written.