Concurrency control in a system for distributed databases (SDD-1)
ACM Transactions on Database Systems (TODS)
The serializability of concurrent database updates
Journal of the ACM (JACM)
Consistency in Hierarchical Database Systems
Journal of the ACM (JACM)
A Theory of Safe Locking Policies in Database Systems
Journal of the ACM (JACM)
The notions of consistency and predicate locks in a database system
Communications of the ACM
Compatibility and commutativity in non-two-phase locking protocols
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
Notes on Data Base Operating Systems
Operating Systems, An Advanced Course
Operation specific locking in B-trees
PODS '87 Proceedings of the sixth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Synchronizing Transactions on Objects
IEEE Transactions on Computers
Principles and realization strategies of multilevel transaction management
ACM Transactions on Database Systems (TODS)
Semantics-based concurrency control: beyond commutativity
ACM Transactions on Database Systems (TODS)
IEEE Transactions on Software Engineering
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Many database systems maintain the consistency of the data by using a locking protocol to restrict access to data items. It has been previously shown that if no information is known about the method of accessing items in the database, then the two-phase protocol is optimal. However, the use of structural information about the database allows development of non-two-phase protocols, called graph protocols, that can potentially increase efficiency. Yannakakis developed a general class of protocols that included many of the graph protocols. Graph protocols either are only usable in certain types of databases or can incur the performance liability of cascading rollback. In this paper, it is demonstrated that if the system has a priori information as to which data items will be locked first by various transactions, a new graph protocol that is outside the previous classes of graph protocols and is applicable to arbitrarily structured databases can be constructed. This new protocol avoids cascading rollback and its accompanying performance degradation, and extends the class of serializable sequences allowed by non-two-phase protocols. This is the first protocol shown to be always as effective as the two-phase protocol, and it can be more effective for certain types of database systems.