I'm just getting acquainted with the interfaces exposed by Cassandra via JMX (presently have 0.4.2 installed). I'm curious is someone can explain to me how to use the 'setLog4jLevel' operation in org.apache.cassandra.service StorageServices. I've tried invoking for various values of p1 (e.g. log4j.rootLogger, org.apache.log4j.rootLogger), and p2 = DEBUG (or INFO).

I always get a message in system.log similar to the following...

set log level to DEBUG for classes under 'org.apache.log4j.rootLogger' (if the level doesn't look like 'DEBUG' then log4j couldn't parse 'DEBUG')

... but there appears to be no effect on the log level.

I assumed this operation would allow me to change the log level on-the-fly. Am I misunderstanding how to use this function? Any insight or direction would be appreciated.