title: Are Mongo PHP write operations Sync or Async?
body: <p>I would like to find out how Mongo writes to disk by default. Async or Sync?</p>
  
  <p>When I do:</p>
  
  <pre><code>$collection-&gt;insert(array("a" =&gt; 42));
  </code></pre>
  
  <p>is it sync? The documentation says the param <code>w</code> is set to <code>1</code> by default and that should cause the <code>insert</code> to return <strong>only</strong> when data has been written to disk. As opposed to <code>w =&gt; 0</code> (Unacknowledged) where data are actually written in an asynchronous way (fire and forget).</p>
  
  <p>So my questions are</p>
  
  <ol>
  <li>Can anyone confirm my observations above?</li>
  <li>It seems to me it follows that <code>insert</code> only throws <code>MongoCursorException</code> when in sync mode (<code>w =&gt; 1</code>), am I right?</li>
  </ol>