index problems after update

[Hajo Locke]

Hello,

Am 21.02.2019 um 10:51 schrieb Aki Tuomi via dovecot:
> On 21.2.2019 10.53, Hajo Locke via dovecot wrote:
>> Hello,
>>
>> Am 20.02.2019 um 10:39 schrieb Aki Tuomi via dovecot:
>>>> On 18 February 2019 09:28 Hajo Locke via dovecot
>>>> <dovecot at dovecot.org> wrote:
>>>>
>>>>
>>>> Hello,
>>>>      it seems we need a dovecot developers opinion. May be we hit a
>>>> bug or cant help ourselves.
>>>>     
>> Thanks for your answer.
>>> Core dump with backtrace would help, if possible to acquire. Please
>>> refer to https://dovecot.org/bugreport.html for information how to
>>> get a core dump.
>>>
>>> Aki
>>>
>> Unfortunately its hard to get a backtrace because dovecot is not
>> crashing. so it seems to be more a kind of logic problem in code and
>> no unexpected situation.
>> yesterday evening i had next incident. I upgraded from 2.2.33.2 to
>> 2.2.36.1, but same behaviour. Also 2.2.36.1 is tricked by the broken
>> index and delivers no new mails. it starts delivering if i delete
>> index files. At this point i cant tell if 2.2.36.1 also has same bug
>> and writes a damaged index, but very likely.  We dont know this
>> problems with 2.2.22, between 2.2.22 and 2.2.33.2 a change on
>> mbox-index code must happend which leads to this big problem. So imapd
>> cant do what he was created for.
>>
>> For next incident i prepared a 2.3.2.1 on base of Ubuntu 18.10 and
>> will try this. In my opinion this is a major problem and i expect a
>> lot of affected people with version > 2.2.22 and classic mbox-storage.
>>
>> Thanks,
>> Hajo
> We consider mbox + procmail setup somewhat edge case, and if the core
> dump does not point into something more generic, it will probably not
> get fixed. It is more likely to have this working if you use
> dovecot-lda/lmtp with sieve instead of procmail.
>
> Aki
>
>
I think mbox+procmail is a classic setup and wide used and good solution 
for many usecases. Same setup we use many years.
We run ~2 mio mailboxes. our automated systems depends on this setup. 
creating mailboxes, managing mailboxes, creating automated filterrules, 
backupsystem to tell something of them. we can not switch our whole 
mailsetup to work around this bug.
How to get a dump if dovecot not crashing but has wrong behaviour? I 
would like to help and provide useful info, but it depends on kind of 
problem.
I think if a classic setup is not working in dovecot any more, this is a 
serious problem.

Thanks,
Hajo