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From "Pete Haidinyak" <javam...@cox.net>
Subject Re: hash function per table
Date Sun, 20 Mar 2011 20:03:25 GMT
I went through this discussion a month or so ago and came away with the  
opinion that you can either have an efficient load with random key but  
then have an inefficient 'scan' not using start and end rows, or have an  
inefficient import with sequential key and then scan using start and end  
rows.

-Pete


On Sun, 20 Mar 2011 12:52:24 -0700, Oleg Ruchovets <oruchovets@gmail.com>  
wrote:

> Actually discussion started from this post:
>
>
> http://search-hadoop.com/m/XX3nW68JsY1/hbase+insertion+optimisation&subj=hbase+insertion+optimisation+
>
> Simply inserting the data in which row key <date>_<somedata> I noticed  
> that
> only one node works (region to which data were writing). In case we have
> 10-15 nodes I think it is inefficient to write data to only one region. I
> want to get an effect that data will be inserted to  as much as possible
> nodes  simultaneously. Correct me guys ,  but in this case  writing job
> will take less time , am I write?
>
> Oleg.
>
> On Sun, Mar 20, 2011 at 8:57 PM, Chris Tarnas <cft@email.com> wrote:
>
>> There is none - HBase uses a total order partitioner. The straight key
>> value itself determines which region a row is put into. This allows for  
>> very
>> rapid scans of sequential data, among other things but does mean it is
>> easier to hotspot regions. Key design is very important.
>>
>> -chris
>>
>> On Mar 20, 2011, at 11:41 AM, Lior Schachter wrote:
>>
>> > the hash function that distributes the rows between the regions.
>> >
>> > On Sun, Mar 20, 2011 at 8:36 PM, Stack <stack@duboce.net> wrote:
>> >
>> >> Hash?  Which hash are you referring to sir?
>> >> St.Ack
>> >>
>> >> On Sun, Mar 20, 2011 at 10:06 AM, Lior Schachter  
>> <liors@infolinks.com>
>> >> wrote:
>> >>> Hi,
>> >>> What is the API or configuration for changing the default hash  
>> function
>> >> for
>> >>> a specific htable.
>> >>>
>> >>> thanks,
>> >>> Lior
>> >>>
>> >>
>>


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