Only One reducer can get the total log num

[paradisehit]

 
 
 I use the script like this:
querys = GROUP clear_log  ALL PARALLEL 4;
TOTAL = FOREACH querys GENERATE FLATTEN(clear_log.($1, $2)), COUNT($1);

STORE TOTAL INTO 'total';

AND I see the monitor page in the hadoop jobtracker, and I see that only one 
reduce process the data, and other 3 reducers just process 0M data?

I think this should be changed, but how can I change it? 

Help me!!