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

[Rodrigo Trujillo]

On 12/14/2015 04:27 PM, Paulo Ricardo Paz Vital wrote:
>
> 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.
You are right Paulo, data is not included (as I firstly thought), just 
schema is modified by wok.

>
>>>> 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
>>>>>
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