title: When does BigQuery flush the streaming output buffer
body: <p>I know this question has been asked in a different form a while ago. But now that BQ allows DML on partitioned table, its more important to understand when the streaming buffer is flushed so that we can perform DML on tables for maintenance. </p>
  
  <p>This is very important now since </p>
  
  <ul>
  <li>I have 1500 partitioned tables.  </li>
  <li>Each table has atleast 200
  partitions.</li>
  </ul>
  
  <p>Now I have to update all the tables since we are performing some sort of hashing for GDPR. </p>
  
  <p>If I cant run the DML, then
  I have to restate the 200 * 1500 partitions by joining with a reference table. </p>
  
  <p>If I can run the DML then I just have to run 1500 udpate statements. </p>
  
  <p>I have stopped the streaming and have been waiting since > 90 minutes and yet still get the same error that I cant run DML since the table has streaming buffer. Any response with your own experience would be highly appreciated. </p>