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From Denis Magda <dma...@apache.org>
Subject Re: Logical Cache Documented
Date Tue, 03 Oct 2017 19:31:38 GMT
Sam,

Is there any technical limitation that prevents us from assigning caches with similar parameters
to relevant groups on-the-fly?

After finishing the doc, I’m convinced the feature should be enabled by default unless there
are some pitfalls not known by me.

BTW, decided to avoid logical caches term usage falling back to vivid cache groups notion:
https://apacheignite.readme.io/docs/cache-groups <https://apacheignite.readme.io/docs/cache-groups>

—
Denis

> On Oct 3, 2017, at 12:10 AM, Semyon Boikov <sboikov@gridgain.com> wrote:
> 
> Hi,
> 
> Regarding question about  default cache group: by default cache groups are
> not enabled, each cache is started in separate group. Cache group is
> enabled only if groupName is set in CacheConfiguration.
> 
> Thanks
> 
> On Sat, Sep 30, 2017 at 11:55 PM, <dsetrakyan@apache.org> wrote:
> 
>> Why not? Obviously compression would have to be enabled per group, not per
>> cache.
>> 
>> ⁣D.​
>> 
>> On Sep 29, 2017, 10:50 PM, at 10:50 PM, Vladimir Ozerov <
>> vozerov@gridgain.com> wrote:
>>> And it will continue hitting us in future. For example, when data
>>> compression is implemented, for logical caches compression rate will be
>>> poor, as it would be impossbile to build efficient dictionaries in
>>> mixed
>>> data pages.
>>> 
>>> On Sat, Sep 30, 2017 at 8:48 AM, Vladimir Ozerov <vozerov@gridgain.com>
>>> wrote:
>>> 
>>>> Folks,
>>>> 
>>>> Honesly, to me logical caches appears to be a dirty shortcut to
>>> mitigate
>>>> some inefficient internal implementation. Why can't we merge
>>> partition maps
>>>> in runtime? This should not be a problem for context-independent
>>> affinity
>>>> functions (e.g. RendezvousAffinityFunction). From user perspective
>>> logic
>>>> caches feature is:
>>>> 1) Bad API. One cannot define group configuration. All you can do is
>>> to
>>>> define group name on cache lavel and hope that nobody started another
>>> cache
>>>> in the same group with different configuration before.
>>>> 2) Performance impact for scans, as you have to iterate over mixed
>>> data.
>>>> 
>>>> Couldn't we fix partition map problem without cache groups?
>>>> 
>>>> On Sat, Sep 30, 2017 at 2:35 AM, Denis Magda <dmagda@apache.org>
>>> wrote:
>>>> 
>>>>> Guys,
>>>>> 
>>>>> Another question. Does this capability enabled by default? If yes,
>>> how do
>>>>> we decide which group a cache goes to?
>>>>> 
>>>>> —
>>>>> Denis
>>>>> 
>>>>>> On Sep 29, 2017, at 3:58 PM, Denis Magda <dmagda@apache.org>
>>> wrote:
>>>>>> 
>>>>>> Igniters,
>>>>>> 
>>>>>> I’ve put on paper the feature from the subj:
>>>>>> https://apacheignite.readme.io/docs/logical-caches <
>>>>> https://apacheignite.readme.io/docs/logical-caches>
>>>>>> 
>>>>>> Sam, will appreciate if you read through it and confirm I
>>> explained the
>>>>> topic 100% technically correct.
>>>>>> 
>>>>>> However, are there any negative impacts of having logical caches?
>>> This
>>>>> page has “Possible Impacts” section unfilled:
>>>>>> https://cwiki.apache.org/confluence/display/IGNITE/Logical+Caches
>>> <
>>>>> https://cwiki.apache.org/confluence/display/IGNITE/Logical+Caches>
>>>>>> 
>>>>>> —
>>>>>> Denis
>>>>> 
>>>>> 
>>>> 
>> 


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