title: Importing Tables from BigQuery to Dataflow
body: <p>I have a Dataflow pipeline (Apache Beam 2.1.0) that it first reads a table from BigQuery. (# of instances 4, instance type: n1-standard-16)</p>
  
  <p>Here is the first pipeline w/ a table size: 
  Estimated size      1.2 GB<br>
  BigQueryIO.Read/PassThroughThenCleanup/ParMultiDo(Identity).out0</p>
  
  <p><strong>Job ID: 2017-10-20_12_27_11-78701910582961250</strong></p>
  
  <p><a href="https://i.stack.imgur.com/iKhiC.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/iKhiC.png" alt="enter image description here"></a>   </p>
  
  <p>Now, if I use a larger table:<br>
  <a href="https://i.stack.imgur.com/VaC0J.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/VaC0J.png" alt="enter image description here"></a></p>
  
  <p>Almost twice the size of the above-mentioned table:
  Estimated size      2.27 GB </p>
  
  <p><strong>JobID: 2017-10-18_16_43_55-10743775736175090102</strong></p>
  
  <p>It takes much more. Basically, reading tables from BigQuery became the main bottleneck of my application. How can I tackle this performance bottleneck?    </p>