Nb of reduce tasks when GROUPing

[Vincent Barat]

Hi,

I use this request to remove duplicated entries from a set of input 
files (I cannot use DISTINCT since some fields can be different)

grp = GROUP alias BY key;
alias = FOREACH grp {
  record = LIMIT  alias 1;
  GENERATE FLATTEN(record) AS ... :
}

It appears that this request always generates 1 reducer (I use 0 as 
default nb of reducer to let PIG decide) whatever the size of my 
input data.

Is it a normal behavior ? How can I improve my request time by using 
several reducers ?

Thanks a lot for your help.