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Date: Tue, 22 Apr 2008 20:00:42 +0530
From: Karthik Pattabiraman <pkarthik@yahoo-inc.com>
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To: hbase-dev@hadoop.apache.org
Subject: HBase Performance question
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Hi,

    I am evaluating HBase for a serving system. The requirements are 
fairly simple. Each record comprises a key and a value (size ~4k).

    I set up a small cluster consisting of two boxes and the number of 
records inserted into the table is close to 65K.

   Now I ran a tomcat server on one of the boxes (where the master is 
running). The tomcat server establishes a connection to hbase at start 
and then on each request queries the hbase for the record.

    The benchmarks were not good. I ran the benchmarks for 30 min with 
20 clients (talking to tomcat) and the average response time was 51 ms. 
When I increased the number of clients to 50, the average response time 
increased to 110 ms. To ensure that tomcat is not the bottleneck, I 
logged the time taken for each Hbase request and found that to be 
correlating the benchmarks (time increased when i increased the number 
of clients.).

    Any idea as to why this would happen given that the number of 
records is not huge? (FYI: Both the boxes act as region servers, the box 
where tomcat runs, also runs hbase master and the dfs namenode)

    Could it be due to the way I have set up Hbase?

    Any help would be appreciated.

thanks

karthik