Background

For Java projects, quartz is used to schedule tasks, and then a strange problem occurs. When adding job scheduling, it is found that the status of write scheduled tasks directly becomes error, or it becomes error after running once or twice. At that time, I was still wondering how this could happen. It is OK to check the log and send modern codes without errors. Manual execution is OK. Then I found that two services are running the same database

Quartz timing task is configured in the database

Then it is found that a server has a very old version of code, so that the corresponding job class cannot be found at runtime, and then the state directly changes to error. Just turn off the older services. Or the two service codes are consistent

terms of settlement

1. Check which service processes are scheduled in the current database

SQL command:   show   processlist;

It will display the of all processes accessing the database you specify

  Then find the corresponding server, update the code or stop one of the services