![]() For updates without indexes, every row in a table gets locked, for example. MySQL might lock many more rows than you might expect, especially when you do not have proper database indexes for the relevant statement. I know how to produce deadlock with 2 processes but am unable to produce it with more than two processes. ![]() So theres a risk that concurrent transactions will have timing such that they each lock one of these indexes and then wait for the other transaction. How to Simulate deadlock with more than 2 processes in SQL Server test environment Can someone help me with the code Just to clarify my question again, I dont want deadlock simulation with only 2 processes. The relevant section of the official manual Show snapshot is pretty good. It seems that it doesnt lock both unique keys atomically, which it should do. While it keeps out of your way usually, it's actually pretty complex. If you still cannot see what actually happened, you might need to get better acquainted with MySQLs locking model. This will show you the most recent deadlock, including the two competing queries and a list of the locks held by both transactions. To get a rough idea what was actually going on, you can run Chances are, you are not properly scoping something. This error states the SQL statement that this thread was currently waiting for, and that tried to acquire one of the competing locks.įirst, always go through the exception backtrace of your application, and look out for code that might operate on data it actually shouldn't. ![]() MySQL should always detect the deadlock right when it happens, and will throw an error to one of the offending threads. Solving deadlocks is potentially complicated, so here are a few pointers:
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