The sever variable (global scope only) binlog_cache_size is actually per connection. Please change the documentation to mention this explicitly.

Also, I am wondering what is max_binlog_cache_size: https://mariadb.com/kb/en/library/replication-and-binary-log-server-system-variables/#max_binlog_cache_size
It refers to binlog_cache_size but nothing of that is mentioned there. Can you elaborate on this documentation a bit?

Perhaps Elkin can you elaborate a bit?