[Kimchi-devel] [PATCH] [Kimchi] Update Kimchi objectstore versioning.

[Paulo Ricardo Paz Vital]

On 12/14/2015 04:09 PM, Rodrigo Trujillo wrote:
> 
> 
> On 12/14/2015 03:20 PM, Paulo Ricardo Paz Vital wrote:
>> On 12/14/2015 01:06 PM, Rodrigo Trujillo wrote:
>>> This solution works for Kimchi and Ginger now, but I analyzed it a bit
>>> deeper and I cannot see it as a good long-term solution.
>> I think the first and most important point you should see here is that
>> Wok provides the objectstore structure for any plugin wants to use it.
>> So, since a plugin is using the Wok's objectstore structure, the
>> solution will works.
>>
>> Second, this change came from a Ginger and GingerBase issue regarding
>> the missing 'version' field on their structure, something solved in
>> Kimchi by commit 50b104a46e65047dfdf299ff8a5f652f2422a949.
>>
>> In addition, this patch depends on Wok's patch I sent a little bit early.
>>
>>> Reasons:
>>> - other plugins will never be allowed to have a column named version in
>>> its table, for whatever reason they want;
>> It's false. Once a plugin is using Wok's ObjectStore structure, a column
>> version will be present starting on version 2.0.0. See commit
>> fec97768abc8b407d4eaaca2fc892708da7210c9
> I see. I thought that version was tied to Wok's version...
>>
>>> - every new record must have the version inserted, today we cannot
>>> measure the impact, but, if for some reason objectstore must be heavily
>>> used, this can impact;
>> The complexity to record the version is the same of any other
>> information, since it's done once - when all information is recorded.
> I was talking about disk space and time to save/retrieve information.
> 
>>
>>> - we will have (or each plugin will have) to change this in future,
>>> because all 'object' tables will have 'version' column, then each plugin
>>> will have to manage by itself how to check and update the records or
>>> schemas;
>> Kimchi already fixed this. Patches to Ginger and GingerBase was already
>> submitted to Ginger ML.
> Thats why I said that works only for Kimchi/Ginger[Base] ...
> WOK should be independent of plugin, what I see, is that wok is being
> used to fix problems that the plugins should fix.
> 
> Actually, plugins will have to check the version of records in the future.
> 

Now I understood what you were talking. Your point is correct, and the
solution proposed is doing exactly that - plugins is checking if version
is present.

However, IMO, it's Wok's responsibility to provide the tools to do this,
and that is what Wok and Kimchi patches are doing - moving the methods
to check and upgrade the objectstore schema, that is the same code for
all plugins, to Wok.

>>
>>> - finally, I think that Wok should not touch plugins 'objectstore'.
>>>
>> Why not? It's a common infra-structure provided and that any plugin can
>> use. All current plugins (kimchi, ginger and gingerbase) that use
>> objectstore have a solution to this problem.
> 
> Bacause Wok is modifying what should be a private database.
> Its ok Wok provides the infra (creates the db, provide functions to
> add/remove/update, etc), it should not
> touch the data.
> 

But Wok is not doing that. The only modification that Wok will do, but
only if plugin request to do, is upgrade the objectstore schema. Not
it's data.

Data update methods still reside on src/wok/plugin/kimchi/utils.py file.

>>> Like I said, this solution works for Kimchi/Ginger now, and I am ok,
>>> once we are running out of time.
>>> But keep in mind , that we are going to have rework in future.
>>> Aline can decide what to do.
>>>
>>> Reviewed-by: Rodrigo Trujillo <rodrigo.trujillo at linux.vnet.ibm.com>
>>>
>>>
>>> On 12/14/2015 11:46 AM, pvital at linux.vnet.ibm.com wrote:
>>>> From: Paulo Vital <pvital at linux.vnet.ibm.com>
>>>>
>>>> This patch is part of the solution for the Ginger Issue #51 and it
>>>> depends on
>>>> Wok's "Upgrade objectstore schema" patch.
>>>>
>>>> With the new structure of the objectstore changed in Wok 2.0.0, the
>>>> schema of
>>>> the objectstore file needs to be checked and, if necessary, updated to
>>>> reflect
>>>> the new structure.
>>>>
>>>> This patch removes from Kimchi the methods used to check the
>>>> objectstore schema
>>>> and upgrade it if necessary. These methods are now present in
>>>> wok.plugins and
>>>> are common to any Wok plugin.
>>>>
>>>> Paulo Vital (1):
>>>>     Update Kimchi objectstore versioning.
>>>>
>>>>    root.py  |  4 ++--
>>>>    utils.py | 40 ----------------------------------------
>>>>    2 files changed, 2 insertions(+), 42 deletions(-)
>>>>
>>>> -- 
>>>> 2.5.0
>>>>
>>>> _______________________________________________
>>>> Kimchi-devel mailing list
>>>> Kimchi-devel at ovirt.org
>>>> http://lists.ovirt.org/mailman/listinfo/kimchi-devel
>>>>
>> _______________________________________________
>> Kimchi-devel mailing list
>> Kimchi-devel at ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/kimchi-devel
>>
> 
> _______________________________________________
> Kimchi-devel mailing list
> Kimchi-devel at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/kimchi-devel
>