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HBase, mail # user - Coprocessor Increments


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Re: Coprocessor Increments
Ted Yu 2013-10-12, 14:42
John:
When RegionObserver increments a well known row in the same region as the
write, a hotspot is created in that region: every write would update that
row.
Bigger issue is that if you allow the regions to split, evaluating the
initial values for the special row in the daughter regions at time of split
would be not so fast. It depends on your use case whether you want to keep
the value in the 'Total' row accurate all the time.

Looks like Tom's method could be a better fit for you.

Cheers
On Fri, Oct 11, 2013 at 6:06 PM, John Weatherford <
[EMAIL PROTECTED]> wrote:

> OP Here :)
>
> Our current design involves a Region Observer on a table that does
> increments on a second table. We took the approach that Michael said and
> inside the RO, we got a new connection and everything. We believe this is
> causing deadlocks for us. Our next attempt is going to be writing to
> another row in the same table where we will store the increments. If this
> doesn't work, we are going to simply pull the increments out of the RO and
> do them in the application or in Flume.
>
> @Tom Brown
>   I would be very interested to hear more about your solution of
> aggregating the increments in another system that is then responsible for
> updating in Hbase.
>
>  -jW
>
>
> On Fri 11 Oct 2013 10:26:58 AM PDT, Vladimir Rodionov wrote:
>
>> With respect to the OP's design… does the deadlock occur because he's
>>>> trying to update a column in a different row within the same table?
>>>>
>>>
>> Because he is trying to update *row* in a different Region (and
>> potentially in different RS).
>>
>> Best regards,
>> Vladimir Rodionov
>> Principal Platform Engineer
>> Carrier IQ, www.carrieriq.com
>> e-mail: [EMAIL PROTECTED]
>>
>> ______________________________**__________
>> From: Michael Segel [[EMAIL PROTECTED]]
>> Sent: Friday, October 11, 2013 9:10 AM
>> To: [EMAIL PROTECTED]
>> Cc: Vladimir Rodionov
>> Subject: Re: Coprocessor Increments
>>
>>
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>