The error message you’ve encountered in MySQL, “Deadlock found when trying to get lock; try restarting transaction,” indicates that a deadlock situation has occurred. Deadlocks happen when two or more transactions are waiting for each other to release locks on resources, preventing any of them from progressing further. To resolve this issue, you can follow these steps:
show processlist;Check any update or insert is blocking, if so get the ID from the result and then kill
kill 189889If the above didn’t work , you can check the below points.
Identify the Deadlock:
First, you need to identify the transactions involved in the deadlock. You can check the MySQL error log, which usually contains information about the deadlock, including the queries and transactions that are part of it.
Retry the Transaction:
One straightforward approach is to retry the transaction. You can catch this specific error in your application code and then retry the entire transaction. However, this approach may not be suitable for all scenarios, as it doesn’t prevent future deadlocks.
Analyze and Optimize Queries:
Review the queries involved in the deadlock and ensure they are optimized for performance. Look for missing indexes, inefficient joins, and any other query bottlenecks that may contribute to deadlocks.
Transaction Isolation Level:
Consider using a lower transaction isolation level, such as READ COMMITTED, which can reduce the likelihood of deadlocks. However, be aware that this can also affect data consistency, so evaluate the trade-offs.
SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
Change Locking Strategy:
Review your locking strategy. You may need to change from exclusive locking to row-level or table-level locking, depending on your application requirements.
Lock Timeout:
Adjust the lock timeout settings. You can set a shorter innodb_lock_wait_timeout value to reduce the time a transaction waits for a lock before throwing an error.
SET innodb_lock_wait_timeout = 10; -- Adjust the timeout value as needed
Reorganize Transactions:
Reorganize your transactions to acquire locks in a consistent order. This can help prevent circular waits, a common cause of deadlocks.
Transaction Retry Mechanism:
Implement a transaction retry mechanism in your application code. When a deadlock occurs, your application can automatically retry the transaction a certain number of times before giving up.
Monitoring and Alerting:
Set up monitoring and alerting to be notified of deadlock occurrences. This will allow you to proactively address issues as they arise.
Load Testing and Stress Testing:
Conduct load and stress testing to simulate heavy concurrent usage of your application. This can help uncover potential deadlock scenarios that may not be immediately apparent.
