title: Azure Data Explorer (ADX) Filtered ingestion
body: <p>It is common that JSON log files contain many types of records together. In a Root Cause Analysis, we often want to explore only a specific type of records, which is just a fraction of the data.</p>
  <p>Today, as ADX does not support filtered ingestion, we have no other choice but to repeat the following pattern:</p>
  <ol>
  <li><p>Load all the records to a &quot;raw&quot; table. (Its bad as 90% of that data is junk)</p>
  </li>
  <li><p>Connect the row table to a derived table with an <a href="https://docs.microsoft.com/en-us/azure/data-explorer/kusto/management/updatepolicy" rel="nofollow noreferrer">update policy</a> and with that execute a filter which will get only the records we care about to the derived table.</p>
  </li>
  <li><p>purge the &quot;raw&quot; table.</p>
  </li>
  <li><p>Execute the analytics against the derived table.</p>
  </li>
  </ol>
  <p>Is there a plan to support filtered ingestion? Is there a better way to do this, than what we do today?</p>