Large Mailbox Append Fix

[Ken Murchison]

Bron Gondwana wrote:
> On Mon, 24 Sep 2007 18:45:28 -0400, "Ken Murchison" <murch at andrew.cmu.edu> said:
>> Bron Gondwana wrote:
>>> On Mon, 24 Sep 2007 13:53:28 -0400, "Ken Murchison" <murch at andrew.cmu.edu> said:
>>>> Bron Gondwana wrote:
>>>>> On Sat, 22 Sep 2007 10:44:55 +0100 (BST), "David Carter" <dpc22 at cam.ac.uk> said:
>>>>>> On Sat, 22 Sep 2007, Bron Gondwana wrote:
>>>>>>
>>>>>>> We still need to sync the final last_uid, which may be greater than
>>>>>>> the UID of the maximum message.
>>>>>> Oops, yes. Replacing last_uid for the last batch should be good enough.
>>>>>>
>>>>>>> (though I think there's a separate check later that does that if they
>>>>>>> still don't match... I really should test-case this!)
>>>>>> I don't think so. There is a separate test for UIDLAST if 
>>>>>> do_mailbox_work() finds that it has no messages to UPLOAD.
>>>>> Yeah, you're right.  I've got a simpler rewrite of the patch here that
>>>>> does update_uidlast(mailbox) at the end if there's nothing in the
>>>>> index_list.
>>>> Attached is my rewrite against CVS.  I removed duplicate code that 
>>>> resulted from having one for() loop with a special case if() inside (It 
>>>> not uses a for() loop nested inside a do() loop).  The patch doesn't 
>>>> look simpler because my version of diff appears to be braindead.
>>> This still doesn't guarantee to update UIDLAST in the pathological case
>>> where there are exactly max_count messages to be uploaded, not including
>>> the final message in the list due to a UUID/GUID matchup - at least not
>>> according to my reading of it.
>> Hmm.  I could be wrong, but UIDLAST always gets set in the last batch, 
>> even if the number of messages is a multiple of max_count.  It may be 
>> hard to tell from the diff, since its kind of chopped up.
> 
> Wow, and it's a pain to apply (don't suppose you could generate patches
> with -p1 easily could you?  Quilt likes them that way).  Even applying by
> hand though, it's breaking all over the place!  I'll try and hand import
> it and see what it looks like.
> 
> I still read it as possible failing.
> 
> Can you please consider the following cases:
> 
> Replica last_uid = 2000
> 
> Master last_uid = 3005 (say, with the top couple of messages either deleted
> or just happen to already exist on the other end for some reason like they
> were copied in from another folder)
> 
> max_count = 1000
> 
> a) There are 999 messages which don't exist on the replica, the uid of the
>    highest is 3002
> 
> b) There are 1000 messages which don't exist on the replica, the uid of the
>    highest is 3003
> 
> c) There are 1001 messages which don't exist on the replica, the uid of the
>    highest is 3004
> 
> 
> In each case, what commands are sent?  I see the following:
> 
> a) UPLOAD 3005 <date> [999 messages]\r\n
> b) UPLOAD 3003 <date> [1000 messages]\r\n

I'm pretty sure that base c) will come out:

UPLOAD 3005 <date> [1000 messages]\r\n

Any time we exit the for() loop and msgno > exists, we set 
index_list->last_uid to mailbox->last_uid, even if index_list->count > 
max_count.

I'll test this tomorrow.

-- 
Kenneth Murchison
Systems Programmer
Project Cyrus Developer/Maintainer
Carnegie Mellon University