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From acure <c...@xg.pl>
Subject performance conclusions and questions
Date Mon, 27 Oct 2008 22:58:27 GMT
I have a few questions about performance. First my test harwade:
       AMD Athlon XP 2500+
       1G RAM
       Ubuntu 8.4
       Hbase 0.18  based on temp dir - without hadoop
       HBASE_HEAPSIZE=500
       Java 1.6 sun

I create a simple table with two column family: "name:","lastname:" ;
RowGets and Scanners are executed for this two columns family.
I put there 50000 elements with a random guid rowId.


test 1 - SCANNER READS
create scanner and iterate from 0 element to the last.
  - 50 000 elements
        total time : 19 604 ms (for 50000 elements) [average - 100 runs ]
       average 0.392 ms per one row

  - 200 000 elements
       total time : 80 844 ms (for 200 000 elements) [average - 100 runs ]
       average 0.404 ms per one row

Test 2 - RANDOM READS
create scanner and iterate from 0 element to the last - and put into 
list all rowId
than start a timer and do "getRow" for each element from list in back order.

 - 50 000 elements
        total time: 76 801 ms (for 50000 elements) [average - 100 runs ]
        average 1.53 ms per one row   

 - 200 000 elements
        total time: 333 565 ms (for 200 000 elements) [average - 100 runs ]
        average 1.66 ms per one row   

Results:
     random read is about 4 times slower than scanner read.
     Do you agree with this experiment ? maby you know how to faster hbase ?

Questions:
a) how fast should it be ?
b) how much faster than the random reads should the scaner reads be ?
c) how will parrallel multithread reads affect the performance ?
d) how should it work for 100 threads (with 120 RPC handlers in 
hbase-site.xml) - do you have any experience?
  
tomorrow i will do this test for 10 000 000 rows and the multithread 
killer test :).
   Antoni

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