[Tarantool-patches] [PATCH] net.box: fix fetching of schema of an old version

[Vladislav Shpilevoy]

On 19/04/2020 18:22, Alexander Turenko wrote:
> On Mon, Apr 06, 2020 at 02:39:37PM +0300, Alexander Turenko wrote:
>>>>> The test and the bug are still upgrade related. 'xlog/upgrade' is not
>>>>> called 'xlog/upgrade_called'. It is called just 'upgrade'. For all cases
>>>>> when an old snapshot is used to start a new tarantool.
>>>>
>>>> I disagree here. 'upgrade' is not something about working upward an old
>>>> snapshot.
>>>
>>> It is. Because you won't work on the old snapshot forever. You are
>>> going to upgrade anyway. Your bug is for when upgrade is started but
>>> not finished. Because Tarantools are new, but upgrade() is not called
>>> yet.
>>
>> It is like "sooner or later a user will use feature X after Y, so let's
>> call Y as X". I understood your point, but still think that the name
>> 'upgrade' is misleading. More general 'snap' or 'snapshots' looks better
>> for me.
>>
>> In fact upgrade may break old connectors (say, due to unicode_ci
>> collation of _func on 2.2) and I guess the old schema may be kept for
>> quite long time so.
> 
> We should agree on some name for directory(-ies) with snapshots for
> testing purposes.
> 
> I think that stored snapshots may be used to test various scenarious:
> 
> * Start from a snapshot with old schema and data, then call upgrade and
>   test a scenario.
> * Start from a snapshot with old schema and some data, then test a
>   scenario.
> * Start from a snapshot that is broken by a past upgrade (see #4804),
>   then test a scenario.
> * Start from a broken snapshot and test a scenario:
>   - A snapshot that violates some constraint (and so is hard to be
>     generated on demand), see #4797.
>   - A snapshot that has broken metainformation: instance uuid, vclock.
> 
> So I would prefer a name that is more general then 'upgrade': 'snap',
> 'snapshots'.
> 
> Aren't this convince you?
> 
> WBR, Alexander Turenko.

Snap looks ok. If it will be used consistently and everywhere.