How Can I close dead session in Impala 2.3.0

[Dong Bo 董博]

Hi guys,

         Due to some reason , some session on impala hangs but not closed , 
service_thread is full and no more new session can be setup , but the client of 
dead session is no longer exist, just Increase service_thread is not a solution 
cause it just extends a little bit the service time .
         Is there any variable or solution can be set to manage this kind of 
dead sessions ?
         Tried option �Cidle_session_timeout , but this option only set the 
session expire to TRUE but can’t close it .

         Impala Version : 2.3.0

Thanks
Carl