// 1. Write the lock column
lockColumn = MessageQueueEntry.newLockEntry(MessageQueueEntryState.None);
long curTimeMicros = TimeUUIDUtils.getTimeFromUUID(lockColumn.getTimestamp());
m = queue.keyspace.prepareMutationBatch().setConsistencyLevel(queue.consistencyLevel);
m.withRow(queue.queueColumnFamily, shardName).putColumn(lockColumn, curTimeMicros + queue.lockTimeout, queue.lockTtl);
m.execute();
// 2. Read back lock columns and entries
ColumnList<MessageQueueEntry> result = queue.keyspace.prepareQuery(queue.queueColumnFamily).setConsistencyLevel(queue.consistencyLevel).getKey(shardName)
.withColumnRange(ShardedDistributedMessageQueue.entrySerializer
.buildRange()
.greaterThanEquals((byte) MessageQueueEntryType.Lock.ordinal())