firefox - Multiple Ajax requests for same URL

Question

I make asynchronous call for same URL for multiple times, But the response came as sequentially. Please see the attached image, The request has been started only after first request completes, the same happening for subsquent requests.

But If the URL is different the responses are not sequential. Please confirm me if one URL is being requested, wouldn't firefox make another request for same URL?

Answer 1

Necko's cache can only handle one writer per cache entry. So if you make multiple requests for the same URL, the first one will open the cache entry for writing and the later ones will block on the cache entry open until the first one finishes. There's work ongoing to rearchitect the cache to remove this restriction.