670933 - ThunderBird hangs for a long time when checking many IMAP mailboxes in Windows 2003 Server TS session

Status: RESOLVED DUPLICATE of bug 574669

(MailNews Core :: Networking: IMAP, defect)

Description

[Jim Klimov]

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; WOW64; Trident/4.0; Maxthon; MRA 5.5 (build 03122); GTB7.1; .NET CLR 2.0.50727; .NET CLR 1.1.4322; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)

Steps to reproduce:

One user has several dozen IMAP mailboxes attached to her Thunderbird configuration (checking many service accounts to filter out received SPAM). When TB is checking these accounts it often hangs for minutes and any TB windows become unresponsive.
From what I've read, the hang itself may be due to a Microsoft security precaution, limiting the number of similar sockets. As the system is a remote terminal server, it is not an option to hack around that precaution.
And since this TB instance spends more than half of the time hanging, actually using it for interactive communications (such as writing emails) becomes tricky. Especially since after upgrade from 3.1 to 5.0 it began forgetting the text which was entered "blindly".


Actual results:

1) When the multiple IMAP mailboxes were checked, TB hanged for a long time with all windows being unresponsive. There were no errors after the checks completed and messages were successfully received and spam-filtered.
2) If a message was being edited in TB 5.0, any changes entered while it was hanging were often forgotten (if the user left the message-editing window). The entered message changes were usually not forgotten in TB 3.0 and 3.1 even if the user left the window and returned to it when TB got un-hung.
Also any attempts to change the current keyboard layout (via Alt+Shift key combo) lead to forgetting any text entered afterwards.


Expected results:

1) TB windows should not become all unresponsive.
1a) Perhaps there should be a configurable limit on how many (IMAP) connections should be attempted at any one time to work around the hang problem, so even if a hundred mailboxes are configured for checks every 10 minutes each, at most (say) 10 or 20 will be checked simultaneously, then progressing to later boxes as former ones are checked.
1b) Perhaps TB should somehow reuse IMAP connections, if that is possible, instead of firing up new ones for each mailbox (or maybe even each folder? I dont know for certain)

2) "Blind" message editions should not have been discarded.
Something should be done that the message editions while TB is unresponsive are not forgotten. This seems doable, especially since if the window remains "active" while the user is blindly typing, text appears when the window also becomes responsive. Seems that types are only lost if the user Alt-TABs or clicks away from the window, or changes the keyboard layout.

Comment 1

[Wayne Mery (:wsmwk)]

Jim, 
So this happen with Thunderbird 3.1, but is worse in version 5?

Comment 2

[Jim Klimov]

Yes, for the past week or so since the upgrade, it seems worse in 5.0 (regarding Alt-TABs from the message edition window).

Portion of time spent hanging vs. time that the TB windows are useable is ostensibly the same.

Comment 3

[Matěj Cepl]

isn't this a duplicate of bug 574669?

Comment 4

[Jim Klimov]

Yes, I think my bug 670933 and the bug 574669 describe the same problem, however in slightly different aspects and details.
I can also confirm that I haven't seen such freezes for several months now, though I cna't vouch since which release exactly - there have been too many major release numbers last year ;)
Still, good work! :)

Comment 7

[Wayne Mery (:wsmwk)]

(In reply to Jim Klimov from comment #4)
> Yes, I think my bug 670933 and the bug 574669 describe the same problem

Jim, do you still have the same opinion?

Comment 8

[Jim Klimov]

Yes, probably so. WFM, you say? ;)

Comment 9

[Wayne Mery (:wsmwk)]

Assuming you are WFM as well