778884 - Blank tab when loading many tabs from the same domain with EventSource

Status: RESOLVED DUPLICATE of bug 906896

(Core :: Networking: HTTP, defect)

Description

[brmichel]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:14.0) Gecko/20100101 Firefox/14.0.1
Build ID: 20120713224758

Steps to reproduce:

I've opened 20 tabs on the same site (same domain) and didn't close them. This web site use EventSource on each page.


Actual results:

The first 15 tabs are opened correctly. The 5 next show a blank page with 'Connecting...' as a title and a loader. And nothing else happened until I closed one tab, not even a timeout after several minutes.

The browser used one connection for each EventSource on the 15 first tabs and hit a limit. If I increase network.http.max-connections-per-server in about:config, I don't reproduce the problem.


Expected results:

At least, having an error message, not just a blank page.

Ideally, the browser should have not allowed the EventSource to take all the connections and could load the page.

Comment 1

[brmichel]

See https://bugs.webkit.org/show_bug.cgi?id=92670 and https://code.google.com/p/chromium/issues/detail?id=139688 for a similar bug report for webkit and chromium.

Comment 2

[Rob Mueller]

We ran across this problem recently and had to use a hacky workaround.

http://blog.fastmail.fm/2012/11/26/inter-tab-communication-using-local-storage/

I believe the real solution is that EventSource connections should not count towards the total number of connections to a particular domain.

What's particularly annoying is how bad the failure mode is of this. The browser just sits there spinning doing nothing because it believe it's run out of connections to that domain waiting for one to become free, but because they're EventSource connections, by definition they're long term and never become free. This gives users the impression they're something wrong with the website, when it's actually a problem with the browser.