767411 - one-time 5-minute startup hang due to deleting page thumbnails

Status: RESOLVED WONTFIX

(Firefox :: General, defect)

Description

[Justin Dolske [:Dolske]]

I restart to update Nightly, and was saddened to find it was not bringing up a window.

A quick sample showed:

Call graph:
    2524 Thread_1973076   DispatchQueue_1: com.apple.main-thread  (serial)
      2524 start
        2524 main
          2524 XRE_main
            2524 XREMain::XRE_main(int, char**, nsXREAppData const*)
              2524 XREMain::XRE_mainRun()
                2524 nsObserverService::NotifyObservers
                  2524 nsObserverList::NotifyObservers
                  ...many js:blah frames...
                    2524 nsLocalFile::Remove(bool)
                      ...syscalls...

A little dtruss output made the culprit obvious:

stat64("/Users/dolske/Library/Application Support/Firefox/Profiles/xxxx/thumbnails/d/8/f5fb411e3f1eb7f722071ec9d33f8c.png\0", 0x11A3E3998, 0x1)		 = 0 0
lstat64("/Users/dolske/Library/Application Support/Firefox/Profiles/xxxx/thumbnails/d/8/f5fb411e3f1eb7f722071ec9d33f8c.png\0", 0x7FFF5FBFB400, 0x0)		 = 0 0
unlink("/Users/dolske/Library/Application Support/Firefox/Profiles/xxxx/thumbnails/d/8/f5fb411e3f1eb7f722071ec9d33f8c.png\0", 0x7FFF5FBFB400, 0x0)		 = 0 0

So, recent landing of bug 752407 which clears the thumbs from this location. 

Looking at log timestamps, this went on for 5 minutes until the browser window finally came up. That is... bad. :(

I couple days ago I noticed again that bug 754671 was hitting my hard, as my profile had ~1.7GB of thumbnails.

Comment 1

[:Gavin Sharp [email: [e-mail]]]

Oops, I lost track of this after originally seeing it. Bug 752407 and bug 744388 were all fixed in the 16 cycle, so this would have only ever affected 16 nightly users, right? So we don't need to worry about fixing it for 16? Just want to make double-plus sure we don't ship something like this :)

Comment 2

[Tim Taubert [:ttaubert] (inactive)]

(In reply to :Gavin Sharp (use [e-mail] for email) from comment #1)
> Oops, I lost track of this after originally seeing it. Bug 752407 and bug
> 744388 were all fixed in the 16 cycle, so this would have only ever affected
> 16 nightly users, right? So we don't need to worry about fixing it for 16?
> Just want to make double-plus sure we don't ship something like this :)

Yes, this only affects Nightly and Aurora users that need to make the transition from the first version of the solid storage to the latest version. This doesn't affect Beta and Release users.

Comment 3

[Alex Keybl [:akeybl]]

We're going to be backing out bug 744388 from Aurora 16, so I don't believe we'll need to track this till FF17. Please correct me if I'm wrong.

Comment 4

[Alex Keybl [:akeybl]]

We've actually decided to leave bug 744388 in the build. We'll track for FF17 until it's on Beta, given comment 2.

Comment 5

[:Gavin Sharp [email: [e-mail]]]

Just to clarify, from an email summary I wrote earlier:

Aurora users were affected because bug 744388 landed on m-c in the 15 cycle, and was live on Aurora for a bit before being disabled (https://bugzilla.mozilla.org/show_bug.cgi?id=744388#c64). So users of Aurora during that time frame accumulated thumbnails in the roaming profile, which will need to be cleared when they upgraded to a build with bug 752407's fix (which causes bug 767411).

Beta/release users will get bug 744388 and bug 752407 fixes at the same time, so bug 752407's migration step will be a no-op (there is no roaming thumbnail folder to remove). They'll also get bug 754671's fix at the same time, so its migration will also be a no-op.

So all of https://hg.mozilla.org/releases/mozilla-beta/annotate/6b4dcd30fef1/browser/components/thumbnails/PageThumbs.jsm#l350 is guaranteed to be cheap for users upgrading from 15->16.

Comment 6

[:Gavin Sharp [email: [e-mail]]]

Given that the damage here has already been done, I think this is WONTFIX.