![]() ![]() Finally, SQL Server has chosen a victim and rollbacked this session. In this circumstance, both of the sessions conflict each other and cannot proceed. At the same time, session 78 acquired a lock on table B and wanted to acquire a lock on the table A. At first, we will create two tables and insert some random data.Īs we can see that, the session 76 acquired a lock on table A and wanted to acquire a lock on the table B. The killed process is called the deadlock victim.Īfter all these theoretical details, we will simulate a deadlock in SQL Server so that we can reinforce our learnings practically. However, the SQL engine understands that this contention would never end with the help of the lock manager warning and then it decides to kill one process to solve this conflict problem so that the other process can be completed. Under these circumstances, each process cannot continue and begins to wait for others to release the resource. ![]() In terms of SQL Server, a deadlock occurs when two (or more) processes lock the separate resource. Note: To learn more about how to avoid deadlocks, please read The Anatomy of SQL Server Deadlocks and the Best Ways to Avoid Them article. This example mainly explained how deadlock occurs in a scenario. Otherwise, none of them can complete their work.Īfter waiting for a while, the boss decided to abort one of the repairing processes so that one of the plumbers obtain the required resource and can complete his repair. The other one is using a wrench and required a plunger at the same time in his repair. Assume that two plumbers are making some repair in the same bathroom, and one of them is using a plunger and require wrench at the same time in his repair. This locked situation can continue forever if nobody stops it. To handle this problem, we need to clearly understand how it occurs.ĭeadlocks occur when two processes want to access resources that are mutually being locked by each other. This article explains the deadlock definition in SQL Server, and it also mentions how to capture deadlocks with extended events.ĭeadlock is a resource contention issue that occurs between two or more than two processes. ![]()
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