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Clarification of Two Phase Locking in Concurrent Transaction Processing
January 1988 (vol. 14 no. 1)
pp. 122-125

The authors propose a formal definition of the two-phase locking class derived from the semantic description of the two-phase locking protocol, and prove that this definition is equivalent to that given by C.H. Papadimitriou (1979). They present: (1) a precise definition of the two phase locking; (2) a clarification of the occurrence and the order ofall events such as lock points, unlock points, read operations, and write operations of conflicting transactions; and (3) by relaxing some conditions in the given definition, the derivation of a new class called restricted-non-two-phase locking (RN2PL), which is a superset of the class two-phase locking (2PL) but a subset of the class D-serializable (DSR) given by Papadimitriou.

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Index Terms:
two phase locking; concurrent transaction processing; semantic description; locking protocol; lock points; unlock points; read operations; write operations; conflicting transactions; RN2PL; D-serializable; database theory; distributed databases; parallel programming; protocols
P.J. Leu, B. Bhargava, "Clarification of Two Phase Locking in Concurrent Transaction Processing," IEEE Transactions on Software Engineering, vol. 14, no. 1, pp. 122-125, Jan. 1988, doi:10.1109/32.4629
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