I got a pretty reliable way of OOME'ing my region servers. Using a big payload (64MB in my case), a default heap and default number of handlers, it's not too long that all the MonitoredRPCHandlerImpl hold on a 64MB reference and once a compaction kicks in it kills everything.
The issue is that even after the RPC call is done, the packet still lives in MonitoredRPCHandlerImpl.
Will attach a screen shot of jprofiler's analysis in a moment.
This is a blocker for 0.92.0, anyone using a high number of handlers and bigish values will kill themselves.