<response/> element wraps the entire response.
The first child element is
<lst name="responseHeader">, which is intuitively the response header that captures some basic metadata about the response.
0. If a Solr error occurs, then the HTTP response status code will reflect it and a plain HTML page will display the error.
QTime: The number of milliseconds Solr takes to process the entire request on the server. Due to internal caching, you should see this number drop to a couple of milliseconds or so for subsequent requests of the same query. If subsequent identical searches are much faster, yet you see the same
QTime, then your web browser (or intermediate HTTP Proxy) cached the response. Solr's HTTP caching ...