@Override
 protected void afterWriteLocksAcquired(TxInvocationContext ctx, PrepareCommand command)
     throws InterruptedException {
   GMUPrepareCommand spc = GMUHelper.convert(command, GMUPrepareCommand.class);
   Object[] readSet = spc.getReadSet();
   TimSort.sort(readSet, keyComparator);
   acquireReadLocks(ctx, readSet);
 }