Difference between getElapsedTime() and getQTime() in solr for java

I'm u开发者_StackOverflow中文版sing Solr for Java and want to know what is the difference between getElapsedTime() and getQTime(), after optimization solr indexes I'm confused which one is for what.

   SolrServer solrObject = _JpaTemplate.getSolrServerForCore(Constants.SOLR_CORE1);
   UpdateResponse sorlResponse = solrObject.optimize();
   System.out.print(sorlResponse.getElapsedTime());
   System.out.print(sorlResponse.getQTime());

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I'm pretty sure the QTime is the time it takes for the query to execute in Solr whereas the Elapsed Time is the total time taken including the transmission and serialization / deserialization of the results.