title: Cassandra lookup query is quite slow after deleting large bundle of data
body: <p>Currently, I have a cassandra column family with large rows of data, to say more than 100,000. Now, I'd like to remove all data in this column family and the problem came up:</p>
  
  <p><strong>After all data is removed, I execute a lookup query in this column family, the cassandra will take tens of seconds to return a empty query result. And the time cost will increase Linearly when the original data is larger</strong></p>
  
  <p>It is caused by the <strong>tombstone feature</strong> while deleting data from the cassandra database. The lookup speed won't recover to normal until the next GC is fired. See <a href="http://wiki.apache.org/cassandra/DistributedDeletes" rel="noreferrer">Cassandra Distributed Deletes</a>. </p>
  
  <p>Because such query operations are frequently used in my system, I cannot bear the huge latency up to a few seconds.</p>
  
  <p>Would you please give me a solution to this problem?</p>