Global concurrency control

Global concurrency control is like playing a game with your friends where you all want to take turns and make changes to the game board.

Imagine you and your friends are all working on a giant puzzle together. You all want to work on the same puzzle at the same time. But you also don't want to ruin each other's work by putting pieces in the wrong place or knocking over other pieces.

So, the game has to make sure that everyone gets a chance to work on the puzzle without messing it up. This is called global concurrency control.

To do this, the game has to keep track of who's turn it is to make a move and make sure that no one else is making a move at the same time. This way, everyone gets a chance to work on the puzzle without interfering with each other's work.

Similarly, in computer systems, when multiple users or processes try to access the same database or file system, global concurrency control is needed to ensure that everyone can access and modify the data safely.

This is done through mechanisms like locking, where a process or user "locks" a resource and prevents others from accessing it until they are done. Or through versioning, where each user gets their own version of the data to modify until they are ready to "merge" it back into the main version.

In either case, the goal is to make sure that everyone can work on the same data without causing conflicts or errors. Just like with your puzzle game, global concurrency control makes sure that everyone can play together without ruining anyone else's fun.