Hewlett Packard Enterprise Development LP

Tianzheng Wang

Hideaki Kimura

Milind M Chabbi

In example implementations, a method include receiving a request for a lock in a Mellor-Crummey Scott (MCS) lock protocol from a guest user that is context free (e.g., a process that does not bring a queue node). The lock determines that it contains a null value. The lock is granted to the guest user. A pi value is received from the guest user to store in the lock. The pi value notifies subsequent users that the guest user has the lock.

Request of an MCS lock by guests

Hybrid concurrency control in a database transaction is disclosed. A contention value associated with a database object is read. The contention value is dynamically updated based on access patterns of the database object. If the contention value indicates the database object is under high contention, a pessimistic concurrency control mechanism is applied to the database object. An optimistic concurrency control mechanism is applied to the database object if the contention value does not indicate the database object is under high contention.

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Palo Alto, CA, United States of America

Tianzheng Wang