Self-adaptive optimistic concurrency control method

A control method and self-adaptive technology, applied in the database field, can solve problems such as high cost and reduced concurrency, and achieve the effect of preventing performance degradation, avoiding the overhead of locking, and avoiding frequent switching of concurrency strategies

CN101556597BInactive Publication Date: 2011-03-30NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2011-03-30
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a self-adaptive optimistic concurrency control method, which is substantially applied to a multiple user concurrent environment based on a main memory. The method comprises twoconcurrency control methods that an optimistic concurrency control is converted into a pessimistic concurrency control and the pessimistic concurrency control is converted into the optimistic concurrency control; when the system is under the environment of high collision rate, a concurrency control policy is converted into the pessimistic concurrency control from the optimistic concurrency control; and when the system is under the environment of low collision rate, the concurrency control policy is converted into the optimistic concurrency control from the pessimistic concurrency control. According to the elf-adaptive optimistic concurrency control method, compared with the pure optimistic concurrency control method or the pessimistic concurrency control method, the defect that the concurrency capability is reduced under the environment of high collision rate or the unlocking of a lock is avoided, and the concurrency capability of the system can be greatly improved.
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Description

technical field

[0001] The invention relates to an adaptive optimistic concurrency control method, which is mainly applied in the multi-user concurrency environment based on main memory, and belongs to the technical field of databases. Background technique

[0002] The rapid development of information technology has greatly popularized the application of databases. In order to create and manage large amounts of data more effectively and safely, and to store the data for a long time, the Database Management System (DBMS) has become a data storage system. And the core software of data processing, among which the concurrency control mechanism of DBMS has become an important research direction in the database field.

[0003] Concurrency control regards transactions as the basic unit of scheduling. There are mainly three kinds of conflicts in concurrent transactions, which are causing lost modification, breaking integrity constraints and inconsistent reading. These conflicts hav...

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Embodiment Construction

[0055] The technical solution of the present invention will be further described in detail below.

[0056] The core idea of ​​the present invention is to use an "hourglass" as an adaptive controller, and the system uses optimistic concurrency control by default, and controls the change of the concurrency strategy according to the state of the "sand amount" in the "hourglass" during operation, so that It can not only avoid the overhead of locking transactions during operation, but also prevent the performance degradation of optimistic concurrency control in the case of severe conflicts. "Sand amount" refers to the cumulative conflict amount in the system, and adjusts the "sand amount" in the "hourglass" Refers to increasing or decreasing the amount of conflict in the system.

[0057] The adaptive optimistic concurrency control method adopted in the present invention is different from the original optimistic concurrency control method in that a mechanism of accumulative conflict...