Packet size - MySQL Database


I am facing issue to connect Metadata to my MySQL database. The issue concerns packet size "com.mysql.jdbc.PacketTooBigException:Packet for query is too large (4739923 > 1048576)".
I already know that I can change this value by setting the variable max_allowed_packet.

I want to know, why Metadata generates a packet of this size ?
We need a high level of security in my company and I would like to know if I can change settings of Metadata to avoid this limit ?

Thank you