mysql process/thread id?

MySQL & MariaDB Other MySQL® Questions
1

I was doing “mysqldump debug” to review the locks in MySQL, and found the following:

13258871email Locked - write Highest priority write lock
13258871contact Locked - write Concurrent insert lock
13258907email Waiting - write Highest priority write lock
13258907address Locked - write Concurrent insert lock

It seems for pid 13258871, there are actually two threads running. Is this normal? Same thing for pid 13258907.

Thanks