Denis, I start working on the issue
https://issues.apache.org/jira/browse/IGNITE-6925 and now I don't understand
why these properties must be bound to each other?

• If we enable statistics on caches, this does not necessarily mean,  that
we wanted to get some events, we can enable statistics for other reasons.
Conversely, not all events need statistics to be enabled on caches. So we
can’t bind statistics flag to events (subscribe to events when statistics is
enabled or enable statistics, when subscribing to events)
• We can’t set events of interest, when we set not a dummy EventsStorageSpi,
because we don’t know which events are interesting.
• When we set events of interest, it’s not necessary, that these events will
be monitored using EventsStorageSpi, we can also subscribe to events by
events listeners, in this case EventsStorageSpi don’t used.

So, there is no general rule (if ... enabled, then ... must be enabled too).
The only implementation I can propose - is "set MemoryEventStorageSPI
instead of NoopEventStorageSPI when includeEventTypes list is not empty",
but even this implementation may be warranted only in some cases.


Denis Magda-2 wrote
> Let’s simplifying the metrics as a part of this ticket:
> https://issues.apache.org/jira/browse/IGNITE-5796
> <https://issues.apache.org/jira/browse/IGNITE-5796>
> 
> Expanded its scope.
> 
> —
> Denis
> 
>> On Sep 9, 2017, at 2:44 PM, Valentin Kulichenko <

> valentin.kulichenko@

> > wrote:
>> 
>> statisticsEnabled property comes from JCache, BTW.
>> 
>> -Val
>> 
>> On Sat, Sep 9, 2017 at 11:09 AM, Dmitriy Setrakyan <

> dsetrakyan@

> >
>> wrote:
>> 
>>> On Sat, Sep 9, 2017 at 8:56 AM, Denis Magda <

> dmagda@

> > wrote:
>>> 
>>>> Surprise!
>>>> 
>>>> If you want to see cache events then you have to enable one more flag!
>>>> 
>>>> 
> <property name="StatisticsEnabled" value="true"/>
>>> 
>>> 
>>> What is the overhead of this statistics collection?
>>> 
>>> 
>>>> Three flags/beans have to be in the config in total, three! Just to see
>>>> cache events. The API is a mess. Let’s contemplate how to fix it.
>>> 
>>> 
>>> Agree, this is horrible. We need to fix it in 2.3. Is there a ticket?





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