In some situations clients that fetch data from a RS get a LeaseException instead of the usual ScannerTimeoutException/UnknownScannerException.
This particular case should be documented in the HBase guide.
Some key points
- the source of exception is: org.apache.hadoop.hbase.regionserver.Leases.removeLease(Leases.java:230)
- it happens in the context of a slow/freezing RS#next
- it can be prevented by having hbase.rpc.timeout > hbase.regionserver.lease.period
Harsh J investigated the issue and has some conclusions, see