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HBase >> mail # user >> an emtry region


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Re: an emtry region
You're right there - compactions does not merge region boundaries.
They just merge the accumulated (flushed, etc.) storefiles belonging
to each region, for every region thats fragmented over time.

On Fri, Aug 10, 2012 at 2:47 PM, J Mohamed Zahoor <[EMAIL PROTECTED]> wrote:
> No. I just now learnt that compactions does not merge regions... (need to
> verify this in code though).
>
> ./Zahoor
>
> On Fri, Aug 10, 2012 at 2:43 PM, J Mohamed Zahoor <[EMAIL PROTECTED]> wrote:
>
>> Hi
>>
>> I think major compaction does this for you.
>> But any way there is a utility called Merge which will merge adjoining
>> Regions.
>>
>> more here http://hbase.apache.org/book/ops.regionmgt.html
>>
>> ./zahoor
>>
>>
>> On Fri, Aug 10, 2012 at 1:47 PM, samar kumar <[EMAIL PROTECTED]>wrote:
>>
>>> @Zahoor thanks
>>> Looks good.. Is there a way to merge regions automatically??
>>> Assuming there was a split and then lot of deletes on each region. Making
>>> each region quite light weight can we merge those two regions to one
>>> (automatically, like some kind of config)
>>>
>>> On 10/08/12 1:07 PM, "J Mohamed Zahoor" <[EMAIL PROTECTED]> wrote:
>>>
>>> >Look at this post for more about Catalog Janitor
>>> >
>>> >http://blog.zahoor.in/2012/08/hbase-hmaster-architecture/
>>> >
>>> >On Fri, Aug 10, 2012 at 12:45 PM, J Mohamed Zahoor <[EMAIL PROTECTED]>
>>> >wrote:
>>> >
>>> >> Hi
>>> >> Region don't remain for ever.
>>> >> Catalog Janitor chore will scan for unused regions in the META and
>>> >>garbage
>>> >> collect. by default it is triggered every 300 sec. The property
>>> >> "hbase.catalogjanitor.interval" is used for this.
>>> >>
>>> >> ./Zahoor
>>> >>
>>> >>
>>> >> On Tue, Aug 7, 2012 at 4:44 PM, Anoop Sam John <[EMAIL PROTECTED]>
>>> >>wrote:
>>> >>
>>> >>> Hi,
>>> >>> >Now could I merge those two regions or automatically delete that
>>> >>>region.
>>> >>> There is no automatic deletion of regions which will happen within
>>> >>>HBase.
>>> >>> Yes u can write code which can do the merge of the 2 regions so that
>>> >>>only
>>> >>> one region will exists.
>>> >>> Having more and more empty regions(unwanted region) is an overhead
>>> >>>only.
>>> >>>
>>> >>> -Anoop-
>>> >>> ________________________________________
>>> >>> From: samar kumar [[EMAIL PROTECTED]]
>>> >>> Sent: Tuesday, August 07, 2012 4:32 PM
>>> >>> To: [EMAIL PROTECTED]
>>> >>> Subject: Re: an emtry region
>>> >>>
>>> >>> @Syed Thanks for respond
>>> >>>  Lets assume that we had a huge table which got split into two
>>> regions.
>>> >>> Later all the rows for that region was deleted. So now we have one
>>> >>>table,
>>> >>> two regions with the second region empty. Table could possible have
>>> >>>more
>>> >>> that one CF. also can't remove the CF because it is still relevant and
>>> >>> data is present in the first region for that particular CF.
>>> >>> Now could I merge those two regions or automatically delete that
>>> >>>region.
>>> >>> Samar
>>> >>>
>>> >>> On 07/08/12 4:19 PM, "syed kather" <[EMAIL PROTECTED]> wrote:
>>> >>>
>>> >>> > samar kumar,
>>> >>> >
>>> >>> >   If all the rows of an region are deleted what happens to the
>>> >>>region.
>>> >>> >Would it still exist .?
>>> >>> > Yes it will exist . Whenever you create a family HBase will create
>>> >>> >a separate Space for that Column Family . If there data available for
>>> >>> then
>>> >>> >that data will be written to HFile which is create for that column
>>> >>>family
>>> >>> >space. If you need  to remove column family completely you have a
>>> >>>write
>>> >>> >the separate code to handle this
>>> >>> >
>>> >>> >Also what is the cost of having a empty region?
>>> >>> >I also don't have proper explanation for this
>>> >>> >
>>> >>> >
>>> >>> >On Tue, Aug 7, 2012 at 4:03 PM, samar kumar
>>> >>> ><[EMAIL PROTECTED]>wrote:
>>> >>> >
>>> >>> >> Please read the subject as  "an empty region"
>>> >>> >>
>>> >>> >> From:  samar kumar <[EMAIL PROTECTED]>
>>> >>> >> Date:  Tue, 07 Aug 2012 15:57:04 +0530

Harsh J
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB