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Physical Sciences and Mathematics Commons™
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Full-Text Articles in Physical Sciences and Mathematics
A Concurrency Control Algorithm For An Open And Safe Nested Transaction Model, Sanjay Kumar Madria
A Concurrency Control Algorithm For An Open And Safe Nested Transaction Model, Sanjay Kumar Madria
Computer Science Faculty Research & Creative Works
We present a concurrency control algorithm for an open and safe nested transaction model. We use prewrite operations in our model to increase the concurrency. Prewrite operations are modeled as subtransactions in the nested transaction tree. The subtransaction which initiates prewrite subtransactions are modelled as recovery point subtransaction. The recovery point subtransaction can release their locks before its ancestors commit. Thus, our model increases the concurrency in comparison to other nested transaction models. Our model is useful an environment of long-running transactions common in object oriented databases, computer aided design and in the software development process
Timestamp-Based Approach For The Detection And Resolution Of Mutual Conflicts In Distributed Systems, Sanjay Kumar Madria
Timestamp-Based Approach For The Detection And Resolution Of Mutual Conflicts In Distributed Systems, Sanjay Kumar Madria
Computer Science Faculty Research & Creative Works
We present a timestamp based algorithm for the detection of both write-write and read-write conflicts for a single file in distributed systems during network partitions. Our algorithm allows operations to occur in different network partitions simultaneously. When the sites from different partitions merge, the algorithm detects and resolves both read-write and write-write conflicts without taking into account the semantics of the transactions. Once the conflicts have been detected some reconciliation steps for the resolution of conflicts have also been proposed. Our algorithm will be useful in real-time systems where timeliness of operations is more important than response time (delayed commit)