611008 - Thunderbird downloads same message twice (duplicating multiple messages!)

Status: RESOLVED INCOMPLETE

(MailNews Core :: Networking: POP, defect)

Description

[Daniel]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.12) Gecko/20101027 Ubuntu/10.04 (lucid) Firefox/3.6.12
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.15) Gecko/20101027 Thunderbird/3.0.10

Thunderbird -- POP3 account
Thunderbird keeps redownloading already downloaded messages twice
leaving messages on server is set up for 15 days
multiple users downlaod from the same acocunt with the same settings (i don't think this matters though, as in TB 2.0+ no such problem occurred!)

Reproducible: Always

Steps to Reproduce:
1. setup pop3 account
2. leave thunderbird on for two hours to download messages
3. shutdown thunderbird
4. run thunderbird again, levae it online for a while
5. messages are redownloaded (same that have already been download are downloaded again)
Actual Results:  
same messages downloaded twice

Expected Results:  
messages downloaded only once

this is linux report, however same thing happens at the same time for thunderbird on windows !

Comment 1

[Ludovic Hirlimann [:Usul]]

So this sounds like your popstate.dat file gets corrupted.

Can you get us a log showing a double message download using the instructions at https://wiki.mozilla.org/MailNews:Logging ?

Comment 2

[Daniel]

Will try that, although as this happens usually only once a day, I am not sure I will be able to supply the log needed.

Comment 3

[:aceman]

So what is the state of this? Does it happen on Thunderbird 7.
Are those other users accessing the mail account simultaneously?

Comment 4

[Rob]

I used to have this really often, and it stopped happening miraculously after my e-mail provider completed his transition to a new backend.

Hasn't happened since. Logs didn't show anything (the newly downloaded mails showed up as different messages, which is probably the reason that Thunderbird downloaded them again).

Maybe you should check with your e-mail provider, if they're testing stuff on their backend (not that the support people tend to know about that, for me they didn't)

Comment 5

[:aceman]

Yes, this does happen if the email provides is changing message identifiers (UIDLs) on the server. It can do so when it does some big consolidation or a move to other mail backend. It shouldn't do it often or regularly as it would cause a mess for all client programs. If the UIDLs would be reliable, email agents would need to compare contents of each new message to every other message already downloaded. That would be hell slow (if not indexed/cached in some way requiring additional disk space).

Comment 6

[Daniel]

I don't have TB 7.0 as my distro has not provided it so far. Somebody else should test it.

As far as I can see this haven't happened in a while.

Comment 7

[Rob]

I'd have to rephrase my comment above.

I used to have this really often (worse and worse) over a period of more than a year. But it magically disappeared (unrelated to program upgrade) _and_ that disappearance more or less coincided with the implementation of a new webmail interface (& most probably new backend); also, when I provided logs for my problem, the people who looked at them could not see that the duplicates were actually duplicates (so they had different UIDLs).

So best check the logs to see if your duplicates have different UIDLs, and if they do, check with the provider?

Comment 8

[Daniel]

It's not related to a provider. This happens (or used to happen for many different providers).

What the developers and commenters here do not take in account is the multiple user access to some POP3 email accounts and this somehow confusing TB. What if there are 10 users downloading at once, will TB be able to work as it should or will it get confused and redownload?

Possible related: Sometimes, TB announces: "message is gone" (I suspect this happens in the very same moment other user is downloading), but after further request it downloads the new message.

Comment 9

[Wayne Mery (:wsmwk)]

(In reply to Ludovic Hirlimann [:Usul] from comment #1)
> Can you get us a log showing a double message download using the
> instructions at https://wiki.mozilla.org/MailNews:Logging ?

pop3:5 please