concurrency control的意思|示意

Concurrency control, also known as synchronizing access, is the practice of coordinating simultaneous changes to the same data to ensure that those changes remain consistent. This can be done by using various techniques, such as locking, timestamping and serializable transactions.

In general, concurrency control is a system-level process that manages the simultaneous access of multiple users to the same application or database, ensuring that any changes they make do not conflict with each other. This can be important as multiple users can have different views and/or levels of access to the same data.

For example, if two users make changes to the same data simultaneously, one change might overwrite the other. To avoid this, the system must be able to determine which person made the most recent change, and which change should remain. This can be done through various techniques, such as locking, timestamping, and serializable transactions.

Locking is a process in which a user temporarily gains exclusive access to a data item, preventing other users from making any changes to it. This ensures that the user has full control over the data item until they are done with their task.

Timestamping allows a system to keep track of when a change was made to a data item, allowing for an easy way to resolve conflicts between data.

Serializable transactions allow multiple users to work simultaneously on the same data, while also guaranteeing that the outcome will remain consistent. It works by allowing each user to apply changes to their own version of the data, while the system keeps track of all changes, and then applies them all at once once the users are done.

In conclusion, concurrency control is an important process used to ensure that simultaneous access to a system or database remains consistent. It uses various techniques, such as locking, timestamping, and serializable transactions, to ensure that any changes made by multiple users don't conflict with each other.