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Hello Dmitriy!

Of course event_id could identify row. Actually Row structure now is a
question for discuss.
The main feature of HBase that data is stored in sorted rows.

To filter events by time interval we will need to scan all stored data,
when
rowkey is started with event_id. Instead of adding timestamp in rowkey, we
could set
timestamps as a additional column value or qualifier inside row.

Another decision is to start rowkey with  "timestamp + event_id".
In this case we will have events stored by timestamps in HBase.

What type of rowkey will give more efficiency is a question.


On Wed, Apr 30, 2014 at 4:36 PM, Dmitriy Ukhlov <dukhlov at mirantis.com>wrote:

> Hello Igor!
>
> Could you clarify, please, Why do we need "event_id + reversed_timestamp"
> row key?
>  Isn't "event_id" identify row?
>
>

> On Tue, Apr 29, 2014 at 11:08 AM, Igor Degtiarov <idegtiarov at mirantis.com>wrote:
>
>> Hi, everybody.
>>
>> I’ve started to work on implementation of Event in ceilometer on HBase
>> backend in the edges of blueprint
>> https://blueprints.launchpad.net/ceilometer/+spec/hbase-events-feature
>>
>> By now Events has been implemented only in SQL.
>>
>> You know, using SQL  we can build any query we need.
>>
>> With HBase it is another story. The data structure is built basing on
>> queries we need, so
>>
>> to construct the structure of Event on HBase, it is very important to
>> answer the question what queries should be implemented to retrieve events
>> from storage.
>>
>> I registered bp
>> https://blueprints.launchpad.net/ceilometer/+spec/hbase-events-structurefor discussion Events structure in HBase.
>>
>> For today it is prepared preliminary structure of Events in HBase:
>>
>> table: Events
>>
>>     - rowkey:  event_id + reversed_timestamp
>>
>>
>>
>>                   - column: event_type => string with description of event
>>
>>                   - [list of columns: trait_id + trait_desc +
>> trait_type=> trait_data]
>>
>> Structure that is proposed will support next queries:
>>
>> - event’s generation time
>>
>> - event id
>>
>> - event type
>>
>> - trait: id, description, type
>>
>> Any thoughts about additional queries that are necessary for Events.
>>
>> I’ll publish the patch with current implementation soon.
>>
>> Sincerely,
>> Igor Degtiarov
>>
>> _______________________________________________
>> OpenStack-dev mailing list
>> OpenStack-dev at lists.openstack.org
>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>>
>>
>
>
> --
> Best regards,
> Dmitriy Ukhlov
> Mirantis Inc.
>
> _______________________________________________
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>
>
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