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From Skchaudhary <schoudh...@ivp.in>
Subject Hbase Quality Of Service: large standarad deviation in insert time while inserting same type of rows in Hbase
Date Tue, 24 Apr 2012 19:41:29 GMT

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!!

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