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From Doug Meil <doug.m...@explorysmedical.com>
Subject Re: Hbase Quality Of Service: large standarad deviation in insert time while inserting same type of rows in Hbase
Date Wed, 25 Apr 2012 15:01:23 GMT

Hi there-

In addition to what was said about GC, you might want to double-check
this...

http://hbase.apache.org/book.html#performance

... as well as this case-study for performance troubleshooting

http://hbase.apache.org/book.html#casestudies.perftroub




On 4/24/12 9:58 PM, "Michael Segel" <michael_segel@hotmail.com> wrote:

>Have you thought about Garbage Collection?
>
>-Grover
>
>Sent from my iPhone
>
>On Apr 24, 2012, at 12:41 PM, "Skchaudhary" <schoudhary@ivp.in> wrote:
>
>> 
>> I have a cluster Hbase set-up. In that I have 3 Region Servers. There
>>is a
>> table which has 27 Regions equally distributed among 3 Region servers--9
>> regions per region server.
>> 
>> Region server 1 has ---region 1-9 Region server 2 has ---region 10-18
>>Region
>> server 3 has ---region 19-27
>> 
>> Now when I start a program which inserts rows in region 1 and region 5
>>(both
>> under Region Server-1) alternatively and on continuous basis, I see
>>that the
>> insert time for each row is not constant or consistent---there is a lot
>>of
>> variance or say standard deviation of insert time is quite large. Some
>>times
>> it takes 2 ms to insert a row, sometimes 3 ms,sometimes 1000 ms and
>> sometimes even > 3000 ms.Even though data size in rows is equal.
>> 
>> I understand that due to flushing and compaction of Regions the writes
>>are
>> blocked---but then it should not be blocked for larger span of time and
>>the
>> blockage time should be consistent for every flush/compaction (minor
>> compaction).
>> 
>> All in all every time flush and compaction occurs it should take nearly
>>same
>> time for each compaction and flush.
>> 
>> For our application we need a consistent quality of service and if not
>> perfect atleast we need a well visible boundary lines--like for each row
>> insert it will take some 0 to 10 ms and not more than 10 ms(just an
>>example)
>> that even though minor compaction or flush occurs.
>> 
>> Is there any setting/configuration which I should try?
>> 
>> Any ideas of how to achieve it in Hbase.
>> 
>> Any help would be really appreciated.
>> 
>> Thanks in advance!!
>> 
>> -- 
>> View this message in context:
>>http://old.nabble.com/Hbase-Quality-Of-Service%3A-large-standarad-deviati
>>on-in-insert-time-while-inserting-same-type-of-rows-in-Hbase-tp33740438p3
>>3740438.html
>> Sent from the HBase User mailing list archive at Nabble.com.
>> 
>



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