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From y_823...@tsmc.com
Subject Re: HBase reading test
Date Thu, 07 Jan 2010 06:55:31 GMT
Hi,

I've found the root cause of why multiple reading users lower the hbase
performance.
That's because I always new a HTable in a share function, which will make
the region server with meta information being
very busy!
After update following code, the reading performance is fantastic.
    1 concurrent client read: 27 sec
    2 concurrent client read: 28 sec
    4 concurrent client read: 36 sec

public Vector<String> ScanHBase(String tablename,String columnfamily,String
KeyColumn,String StartKeyValue,String StopKeyValue) throws IOException {
      HTable table = new HTable(config, tablename); //-- bad writing

                       .
                       .
                       .
}
                                                                                         
     
 2010/1/3 <y_823910@tsmc.com>                                                      
           
                                                                                         
     
 > Each client fetch the same data(5243 rows)                                         
        
 > The Result is like following:                                                      
        
 >    1 concurrent client read:  80 sec                                               
        
 >    2 concurrent client read: 104 sec                                               
        
 >    3 concurrent client read: 232 sec                                               
        
 > As above, increasing more concurrent client                                        
        
 reading connections seems to                                                            
     
 > lower hbase performance too much.                                                  
        
 > Any opinions?                                                                      
        
 >                                                                                    
        
 >                                                                                    
        
 Clients were all running in a single process?                                           
     
 If so, try running them as                                                              
     
 distinct processes.                                                                     
     
 St.Ack                                                                                  
     
                                                                                         
     
                                                                                         
     





Fleming Chiu(邱宏明)
707-6128
y_823910@tsmc.com
週一無肉日吃素救地球(Meat Free Monday Taiwan)


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