title: data from mutiple mysql tables to hadoop map-reduce
body: <p>We have following scenario:</p>
  
  <p>We have a chain of <code>map-reduce processes</code> implemented in java.Currently we are reading data from a mysql table and saving output to another <code>mysql table</code>.Now we may need data from another table as input to map/reduce process.</p>
  
  <p>Possible Solutions: </p>
  
  <p>a) Either we can have a join query for input to map process or</p>
  
  <p>b) we can read needed data by making simple <code>jdbc connection</code> and requesting data again and again(although, i don't prefer it).</p>
  
  <p>Questions:</p>
  
  <p>What are the best practices in such scenario?
  We may move to <code>mongoDB</code> in future.What will be best practice in that scenario?</p>