title: How to get the row count of a table instantly in DynamoDB?
body: <p>I'm using <code>boto.dynamodb2</code>, and it seems I can use <code>Table.query_count()</code>. However it had raised an exception when no query filter is applied.</p>
  
  <p>What can I do to fix this?</p>
  
  <p>BTW, where is the document of filters that <code>boto.dynamodb2.table.Table.Query</code> can use? I tried searching for it but found nothing.</p>