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HBase >> mail # user >> Decreasing write speed over time


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RE: Decreasing write speed over time
Hi
   Sorry I was not able to access your chart of put perf. Is it like the performance gradually coming down and at some point again getting better all of a sudden?  [some spikes in graph]
It may be because of HBASE-3484

You can check the memstore size that u have given and see whether the spikes coming at the memstore flush time and then again perf going down gradually...

-Anoop-
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From: Giorgi Jvaridze [[EMAIL PROTECTED]]
Sent: Monday, June 18, 2012 7:28 PM
To: [EMAIL PROTECTED]
Subject: Decreasing write speed over time

Hello list,

I have Hbase (CDH4) setup of a master and 4 region servers (8 core 2.0GHz,
6GB of RAM and 6 100GB disks per data node). All of them are virtual
machines.

I'm writing into a table using single thread w/ auto flush off.
Ids are increased by one and then reversed. Data is a string with average
length 150 chars.

I'm measuring time needed for writing one million rows. At first I got
quite good results, it could write about 40-50K rows in a second but after
time this speed decreased.
I have a chart showing how It has been decreased by the time and data got
bigger. At the end of chart it's about 2 billion rows inserted.

http://i.minus.com/iRFtEoVJVsFso.png

Is this expected behavior for this kind of setup or something could went
wrong and I should check it up?

Thanks!

Giorgi