Concurrency control method and device

Abstract

The invention provides a concurrency control method, which comprises the following steps: judging whether locks conflicted with locks to be granted exist at a position of a transaction to be operated according to a lock relation table which is used for storing the relation of the transaction and the locks; granting the locks to the transaction according to a judgment result, and executing the transaction; and when the execution of the transaction is finished, releasing the locks held by the transaction, and granting the locks not needing continuously waiting in the released locks to other concurrency transactions. The invention also provides a concurrency control device, which comprises a judgment module, an execution module and a release module. The method solves the problems of low concurrency and poor system performance of transaction control by a concurrency method in related technology so as to improve the concurrency of the transaction control and concurrency control effect.

Description

technical field [0001] The present invention relates to the field of databases, in particular to a concurrency control method and device. Background technique [0002] The database is a shared resource, and there may be multiple concurrently executing transactions in the database system at the same time. When multiple users access the database concurrently, it will cause multiple transactions to access the same database at the same time. For example, transactions T1 and T2 may have the following three conflicts during concurrent execution: [0003] 1) WR (Write / Read, write-read) conflict, that is, T2 reads data that has just been modified by T1 and has not yet been committed, so that T2 reads dirty data, also known as "dirty read"; [0004] 2) RW (Read / Write, read-write) conflict, that is, T2 modifies the data just read by T1 and T1 has not yet ended, so if T1 reads the same object again, its value will change, also known as "impossible repeat read"; [0005] 3) WW (Writ...

AI Technical Summary

Problems solved by technology

[0010] The present invention aims to provide a concurrency control method and device, which can solve the concurrency control method in the related art so that all other concurrent transactions that request to operate on the same database record enter the waiting queue until the locked transaction is executed and the lock is released After that, other concurrent transactions can operate on the database again, resulting in low concurrency of transaction control and poor system performance.

Images