How to implement lock and unlock in php?

How to implement locking and unlocking in php: 1. Use MySQL's locking mechanism to achieve mutual exclusion; 2. Use the file lock mechanism; 3. Use shared memory space counting.

#php method to implement locking and unlocking:

1. Use MySQL’s locking mechanism to achieve Mutually exclusive. The disadvantage is that it increases the connection burden on the database server and makes the program dependent on the database service to work properly.

2. Use the file lock mechanism. That is to say, the flock function is used to implement the locking and mutual exclusion mechanism through files to simulate the working mode of the locking primitive under the general programming model. This method

became a necessary element to protect data integrity in the era when plain text files were used as storage engines. Now it is also quite common when text files are used as caching media.

PmWiki This mechanism should also be used to remind multiple people when they edit a page at the same time. However, the file lock mechanism will somewhat call the file lock feature on the host operating system, so when using it, you must check whether the server operating system provides a complete and reliable file lock mechanism for the PHP environment.

3. Use shared memory space counting

. PHP can use the shmop_open function to open up a memory space and share data between service processes. In order to ensure mutually exclusive safe access to shared data, you can use sem_get,

sem_acquire

and sem_release This set of functions implements the shared count locking mechanism. This method is actually implemented in the background by calling the ipc service of the system .

Related learning recommendations:

PHP programming from entry to proficiency

The above is the detailed content of How to implement lock and unlock in php?. For more information, please follow other related articles on the PHP Chinese website!