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From Ted Yu <yuzhih...@gmail.com>
Subject Re: pre split region server
Date Wed, 16 Jul 2014 09:29:36 GMT
The following command in hbase shell would show you the syntax:
help 'create'

Cheers

On Jul 16, 2014, at 2:07 AM, Shushant Arora <shushantarora09@gmail.com> wrote:

> Thanks Ted.
> 
> Can you tell give shell syntax for #3 at table creation time.
> 
> 
> On Wed, Jul 16, 2014 at 1:52 PM, Ted Yu <yuzhihong@gmail.com> wrote:
> 
>> For #1, the two regions would contain roughly half the data.
>> 
>> For #2, 1 region would not receive new data. As you see, such schema
>> design is suboptimal.
>> 
>> For #3, you can split the key space evenly. Using number of region servers
>> as number of splits is Okay.
>> 
>> Cheers
>> 
>> On Jul 16, 2014, at 12:25 AM, Shushant Arora <shushantarora09@gmail.com>
>> wrote:
>> 
>>> Thanks!
>>> Few more doubts
>>> 
>>> 1.When I don't supply SPLITS at table creation , all put operation will
>> go
>>> to one region only.
>>> But when region grows more than hbase.hregion.max.filesize , then 2
>>> regions will be created both have half-half data or another will be empty
>>> initially?
>>> 2.If both have 50-50% data and row key is monotonically increasing then 1
>>> region will be half filled always and will never be filled again ?
>>> 3.While prespliting table only way is to specify row boundaries and key
>>> prefixes  ?Say if i don't know key ranges , as in my case its GUID
>>> hexadecimal 32 character string , what should be region split boundary ?
>>> and How many splits should be created - is it equal to no of regionserver
>>> aka datanodes ?
>>> 4.For keys of type ACTIVITYTYPE-DATE (where activity type has 2 values
>>> 1.login 2.logout) what should be split strategy ?
>>> 
>>> 
>>> 
>>> On Tue, Jul 15, 2014 at 7:03 PM, Ted Yu <yuzhihong@gmail.com> wrote:
>>> 
>>>> Shushant:
>>>> For #2, if table has only one region, the hosting region server would
>>>> receive all writes.
>>>> For #4, yes - presplitting goes with fixed number of regions.
>>>> 
>>>> Cheers
>>>> 
>>>> 
>>>> On Tue, Jul 15, 2014 at 6:23 AM, sudhakara st <sudhakara.st@gmail.com>
>>>> wrote:
>>>> 
>>>>> You can find info here
>>>>> http://hbase.apache.org/book/rowkey.design.html#rowkey.regionsplits
>>>>> http://hortonworks.com/blog/apache-hbase-region-splitting-and-merging/
>>>>> 
>>>>> 
>>>>> On Tue, Jul 15, 2014 at 6:40 PM, Shushant Arora <
>>>> shushantarora09@gmail.com
>>>>> wrote:
>>>>> 
>>>>>> 1.How to split region servers at table definition time?
>>>>>> 
>>>>>> 2.Will hbase write onto only one region server when no splits are
>>>> defined
>>>>>> even if key is not monotonically increasing?
>>>>>> 
>>>>>> 3. When does a region split occurs.
>>>>>> 
>>>>>> 4. Will no of regions be fixed when hbase table is presplitted at
>> table
>>>>>> creation time.
>>>>> 
>>>>> 
>>>>> 
>>>>> --
>>>>> 
>>>>> Regards,
>>>>> ...sudhakara
>> 

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