Add comment for _prunedSerialNum.
@@ -77,6 +77,7 @@ private:
TlsReplayProgress::UP _tlsReplayProgress;
// the serial num of the last feed operation processed by feed handler.
SerialNum _serialNum;
+ // the serial num considered to be fully procssessed and flushed to stable storage. Used to prune transaction log.
SerialNum _prunedSerialNum;
// the serial num of the last feed operation in the transaction log at startup before replay
SerialNum _replay_end_serial_num;
