Is there a way to check post request parameter size at runtime

I am struggling with the maxPostSize parameter in tomcat server.xml. I increased it from the default 2 MByte to 6 mg to solve some problem that we had, and after one week the problem appears again and I increased the size to 10 MByte. I am not sure if it is a good idea to use the unlimited size.

I am trying to find a way to check this parameter size in run time, for specific post requests.( to find out the source of the problem). is there any way to check this param size at run time?