The problem is that creating a event could fail if the value of
the variable server_id didn't fit in the originator column of
the event system table. The cause is two-fold: it was possible
to set server_id to a value outside the documented range (from
0 to 2^32-1) and the originator column of the event table didn't
have enough room for values in this range.

The log tables (general_log and slow_log) also don't have a proper
column type to store the server_id and having a large server_id
value could prevent queries from being logged.

The solution is to ensure that all system tables that store the
server_id value have a proper column type (int unsigned) and that
the variable can't be set to a value that is not within the range.