set hive.merge.mapfiles = true;
set hive.merge.mapredfiles = true;
set hive.merge.size.per.task = 256000000;
set hive.merge.smallfiles.avgsize=256000000;
set hive.merge.mapfiles = true;
set hive.merge.mapredfiles = true;
set hive.merge.size.per.task = 256000000;
set hive.merge.smallfiles.avgsize=256000000;