MySQL page lock

Page lock is in Page granularity Lock on the , More data resources are locked than row locks , Because a page can have multiple row records . When I When we use page locks , There will be a waste of data , But most of this waste is data rows on a page . The cost of page locks Between table lock and row lock , A deadlock occurs . Lock granularity is between table lock and row lock , The concurrency is average .

There is a limit to the number of locks per level , Because locks take up memory space , The size of the lock space is limited . When the number of locks in a level exceeds the threshold of that level , Lock escalation will occur . Lock upgrade is to replace multiple smaller granularity locks with larger granularity locks , such as InnoDB Upgrade middle row lock to table lock , The advantage of this is that it takes less lock space , But at the same time, the concurrency of data has also decreased .