When I get

Host 'host_name' is blocked because of many connection errors.
Unblock with 'mysqladmin flush-hosts'

error, I checked the manual and it is influenced by the variable
'max_connect_errors', but I don't know this connect_errors is meant
'concurrent' or 'accumulated'?

I mean, will the host be blocked when it reach the max_connect_errors
simultaneously or it will be blocked when all of its history connect
errors has reached the max_connect_errors?

Thank you.