Over-aggressive thread locking?[Solved.]

[timrprobocom]

I've been a Thunderbird user since 2003, so I'm quite comfortable with it's usual performance feel. SOMETHING has changed in the last 6 to 12 months that is causing a significant hit to usability.

My IMAP server is on a sufficiently powerful Linux machine on my local gigabit network. Any time Thunderbird is downloading messages from the IMAP server, the GUI essentially stops responding. Keystrokes and mouse clicks are not acknowledged for many seconds. It doesn't lose keystrokes and clicks, but it feels frozen. It acts as if it had fallen back to being a single-threaded application. I suspect there is new competition for some mutex or interlock that is blocking the UI.

Making it worse, IMAP performance seems to have dropped. I've been out of town for 5 days, and came back to 1,200 unread messages. It knew the count right away, but it took literally 50 minutes for it to download those messages, and the whole time it is downloading, the UI is virtually unresponsive.

When I fetch the IMAP messages with Mac Mail from my MacBookAir at home, I don't see that kind of delay. It will take a minute or two for those 1,200 messages.

I don't know how to chase this. Is there additional logging I could enable? I suppose I could do some Wiresharking to see if there is continuous traffic, or if there are big gaps.
"error"

[timrprobocom]

By the way, I've been searching for weeks for similar reports. If this really were a generic problem, I would certainly not be the only dude in the world to experience it. I've found no applicable matches.

[tanstaafl]

What type of IMAP server - Cygnus, Dovecot, Courier, UnivOfWashington ....?

What version of Thunderbird (according to help -> troubleshooting information or help -> about Mozilla Thunderbird) are you using? Can you remember what version you first saw this problem?

Does the problem go away in safe mode (help -> restart with add-ons disabled)?

See http://kb.mozillazine.org/Performance_-_Thunderbird for some ideas that are not IMAP dependent.

See http://kb.mozillazine.org/Session_logging_for_mail/news for how to enable IMAP logging in Thunderbird.

You said it occurs when downloading. That implies global search and/or offline folders are enabled. Does the problem occur if you temporarily disable one or both features? I'm NOT suggesting this as a workaround, I'm asking to try to see if its component dependent. Both global search/indexing and offline folders use background tasks.

See http://kb.mozillazine.org/Go_back_to_an ... hunderbird if you want to experiment with installing an older version such as 52.9.1 in a different directory (custom setup) to see if its a version dependent problem. It will use your existing profile, and doesn't require you to uninstall the current version.

[tanstaafl]

Consider adding a Gmail IMAP account, temporarily disable checking for new mail in your other account (both check for new mail... and disabling IDLE support in the server settings) , exit Thunderbird, send/forward some messages to the Gmail account via webmail (browser) and then start Thunderbird. That would help identify if the problem is dependent upon your Linux IMAP server or not.

Think about also creating a new profile (just for troubleshooting purposes) and see if it has the same problem with your Linux server. Don't migrate anything from your old profile as that defeats the whole purpose. See http://kb.mozillazine.org/Profile_Manager if you want to try that. You can switch back to your old profile afterwards.

[timrprobocom]

A virtual beer goes to tanstaafl for suggesting "Safe Mode". By using that, I learned that both of the problems described above were, indeed, caused by the "LookOut" add-on, and there is at least one report of similar problems from another user. Thank you very much for the suggestion, things are back to normal.

Shame on me for not correlating my problems to the addition of that add-on.