title: Does timescaledb index works the same as postgreSQL?
body: <p>I am testing an PostgreSQL extension named Timescaledb for time series data.
  If I read the document of PostgreSQL right, the query for example </p>
  
  <pre><code>WHERE x = 'somestring' and timestamp between 't1' and 't2'
  </code></pre>
  
  <p>will work best with index <code>(x,timestamp)</code>. And run <code>EXPLAIN</code> on that SQL query shows that it works.</p>
  
  <p>When I try the same query on Timescaledb hypertable, which contains same data and without index <code>(x,timestamp)</code>. The performance is about the same (if not better). After creating index <code>(x,timestamp)</code>, the performance does not improve.</p>
  
  <p>I understand that the hypertable have a build-in timestamp index. So, I should have a different strategy to add index to the table, for example index with just <code>(x)</code>. Is that right?</p>