MySQL Frequent Deadlocks

What is MySQL Frequent Deadlocks

Identify the transactions involved in the deadlock:

- Run `SHOW ENGINE INNODB STATUS;` to get the latest deadlock information. This command returns a detailed report that includes the last detected deadlock and the transactions involved.

Analyze the deadlock logs:

- Focus on the `LATEST DETECTED DEADLOCK` section to understand which queries were involved and the tables they were accessing.

Capture slow logs for further analysis:

- Enable the slow query log if it's not already enabled: `SET GLOBAL slowquerylog = 'ON';`. - Set the long query time to capture slow queries: `SET GLOBAL longquerytime = 1;` (captures queries longer than 1 second, adjust as needed). - Review the slow query log file. The location can be found by querying: `SHOW VARIABLES LIKE 'slowquerylog_file';`.

Check for lock waits:

- Run `SELECT * FROM INFORMATIONSCHEMA.INNODBLOCK_WAITS;` to identify queries that are currently waiting for locks.

Optimize the involved queries:

- Based on the information gathered from steps 1-4, specifically look to optimize the queries involved in the deadlock. This could involve indexing columns used in joins and where clauses or splitting large transactions into smaller ones.

Monitor locks in real time (optional):

- For ongoing monitoring, you can periodically check `SHOW FULL PROCESSLIST;` to see if there are queries that are stuck or running for a long time, which might indicate locking issues.