set mapred.max.split.size=256000000;
set mapred.min.split.size.per.node=100000000;set mapred.min.split.size.per.rack=100000000;
set hive.input.format=org.apache.hadoop.hive.ql.io.CombineHiveInputFormat;
set hive.merge.mapfiles = true;
set hive.merge.mapredfiles = true ;
set hive.merge.size.per.task = 256000000;
set hive.merge.smallfiles.avgsize=16000000 ;