Re: [Tarantool-patches] [PATCH v2 2/2] wal: reorder tx rows so that a tx ends on a global row

[Serge Petrenko <sergepetrenko@tarantool.org>]

26.05.2020 14:41, Konstantin Osipov пишет:
> * Serge Petrenko <sergepetrenko@tarantool.org> [20/05/26 12:42]:
>> 25.05.2020 19:34, Konstantin Osipov пишет:
>>> * Serge Petrenko <sergepetrenko@tarantool.org> [20/05/25 14:00]:
>>>
>>> While I think it's an acceptable strategy for a bugfix, I still
>>> think relaying has to be fixed to be transactional, the current
>>> xstream api is a huge legacy we're stuck with since Tarantool 1.3!
>>>
>>> It saddens me a great deal the relay patch may be shuffled into
>>> the desk once the problem is not as urgent.
>> Hi! Thanks for your  answer.
>> I understand your concern with transactional relay rework. However, this
>> approach faces some non-trivial problems we discussed verbally. That's why
>> I chose a more simple solution.
>>
>>
>> I have a question regarding this patch. Do you think I should reorder the tx
>> rows
>> so that the last row is a global one? Maybe it'd be better to just set
>> is_commit
>> flag on the last global row? This breaks tx boundaries in local WAL, but
>> preserves
>> them as is in replication and in other instances' WALs. I don't think we'll
>> need tx
>> boundariesin local WAL anyway, but still breaking the invariant that the
>> last tx
>> row has an is_commit flagset to true is scary.
> We will eventually need tx boundaries everywhere, it's just a
> rakes waiting to be stepped on that we added transaction
> boundaries but did not enforce them everywhere.
>
> If you set is_commit flag on the last global row, you will exclude
> local rows from the transaction locally.
> Reordering, but more specifically, simply moving the last global
> xrow to the end of the transaction list, is safer IMHO.
>
Ok, thanks.

-- 
Serge Petrenko