SQL Server data blocking cause

Causes of blockage formation

Because SQL Server is high concurrency, there will be a lot of user access at the same time, in order to ensure data consistency and data security, the introduction of a lock mechanism. At the same time only the user who gets the key is able to access, while the other user needs to wait.

Four necessary conditions for deadlock formation

1. A resource can only be used by one process at a time.

2. When a process is blocked by a request for resources, the resources that are already available remain

3. The resources available to the process cannot be forcibly deprived until it is used

4. A round-the-end cycle waiting relationship is formed between several processes

How to capture deadlocks

1.Profiler

2. Extended Event Trace Deadlock

SQL Server data blocking cause