title: What is role of bloom filter in cassandra?
body: <p>From two different links of the Cassandra's documentation, I found:</p>
  
  <p><a href="http://docs.datastax.com/en/cassandra/3.0/cassandra/dml/dmlHowDataWritten.html" rel="noreferrer">link 1</a></p>
  
  <blockquote>
    <p>A structure stored in memory that checks if row data exists in the memtable before accessing SSTables on disk</p>
  </blockquote>
  
  <p>and </p>
  
  <p><a href="http://docs.datastax.com/en/cassandra/3.0/cassandra/dml/dmlAboutReads.html" rel="noreferrer">link2</a></p>
  
  <blockquote>
    <p>Cassandra checks the Bloom filter to discover which SSTables are likely to have the request partition data.</p>
  </blockquote>
  
  <p>My question is does both the above statements are right? If yes, does bloom filters maintained for a Memtable and SSTable separately? Thanks in advance.</p>