SQL deadlock

I have about 900 monit hosts reporting to a single M/monit VM running CentOS 7.7.  I had to tune out (expand) the network port ranges to handle the simultaneous connections.  Now I have to use monit itself to restart the mmonit service several times a day when this shows up in /var/log/messages.  Is there any documentation or guidelines for setting up and tuning the MariaDB 5.5 database server?  I have a local database on the VM but I could move the DB to a more powerful, physical MariaDB 10.3 cluster if needed.

Oct 29 08:02:08 monit01 mmonit[3956]: SQLException: Deadlock found when trying to get lock; try restarting transaction when storing hostid 12020 statistics
Oct 29 08:02:08 monit01 mmonit: SQLException: Deadlock found when trying to get lock; try restarting transaction when storing hostid 12020 statistics
Oct 29 08:02:21 monit01 mmonit[3956]: SQLException: Deadlock found when trying to get lock; try restarting transaction when storing hostid 6928 statistics
Oct 29 08:02:21 monit01 mmonit: SQLException: Deadlock found when trying to get lock; try restarting transaction when storing hostid 6928 statistics

Thanks,
Dave