Symptoms

When trying to apply space permission for a user/group, an error is thrown and the following appears in the catalina.out:

12-Oct-2017 13:45:56.435 INFO [http-nio-9001-exec-16] org.apache.tomcat.util.http.Parameters.processParameters More than the maximum number of request parameters (GET plus POST) for a single request ([10,000]) were detected. Any parameters beyond this limit have been ignored. To change this limit, set the maxParameterCount attribute on the Connector.

Cause

This occurs due to the fact that Tomcat has reached a maximum number of request parameters when trying to add a user/group into a space permission page. This usually happens when there are many users and groups defined in the space permission. 

Resolution

Add the following attribute to the Connector in the <confluence-install>/conf/server.xml:

maxParameterCount="20000"

The default value is 10000, so the new value should be something higher. In the example above, it is set to 20000. It can also be set to 0 to allow unlimited request parameters.

 Refer to the Apache Tomcat 8 Configuration Reference for the full documentation of this Connector attribute.