"Aggregator_91,0: The current soft limit on the data segment (heap) size (2147483645) is less than the hard limit (2147483647), consider increasing the heap size limit"
This is the error i am getting.... Please advice how to overcome this.
Is this a warning message or an error message causing the job to abort? One option you have is to sort your incoming data according to your aggregation group(s).
In that case your memory requirements for this stage are higher than what the machine can give you. Since you cannot increase your hard data segment size you will need to reduce your storage requirements, which can be done in this case by sorting your data before the aggregator stage.