Naive questions for Hama

["Tu, Min" <mi...@paypal.com>]

Hi,

I am new to Hama and just playing with the example.jar bundled in Hama 0.5.

I have several questions related to the CombineExample.java


  1.  BSPJob.setCombinerClass will call "conf.setClass(COMBINER_CLASS_ATTR, cls, Combiner.class)";however, I can not find where the combiner being called/used
  2.  BSPJob.setNumBspTask will set the number of tasks ( peers ). Here are some data when I try changing this numbers. I can see the TOTAL_MESSAGES_RECEIVED got 3:1 shrinker when I use combiner, however I can not calculate the TOTAL_MESSAGES_SEND or RECEIVED count. For my calculation: 2 peers, one send 3 message to other, the TOTAL_SENT should be 6, and total received should be 2 if use combiner. But the result from program is TOTAL_SENT 24, TOTAL_RECEIVED 4.

CombineExample, task 4, NO combiner
12/10/25 16:07:13 INFO bsp.BSPJobClient:     TOTAL_MESSAGES_SENT=96
12/10/25 16:07:13 INFO bsp.BSPJobClient:     TOTAL_MESSAGES_RECEIVED=48

CombineExample, task 4,  3>1 combiner
12/10/25 16:08:43 INFO bsp.BSPJobClient:     TOTAL_MESSAGES_SENT=96
12/10/25 16:08:43 INFO bsp.BSPJobClient:     TOTAL_MESSAGES_RECEIVED=16

CombineExample, task 2, NO combiner
12/10/25 16:09:36 INFO bsp.BSPJobClient:     TOTAL_MESSAGES_SENT=24
12/10/25 16:09:36 INFO bsp.BSPJobClient:     TOTAL_MESSAGES_RECEIVED=12

CombineExample, task 2, 3>1 combiner
12/10/25 16:10:42 INFO bsp.BSPJobClient:     TOTAL_MESSAGES_SENT=24
12/10/25 16:10:42 INFO bsp.BSPJobClient:     TOTAL_MESSAGES_RECEIVED=4

Really appreciated your time and effort.

Thanks

Min