检查这些设置（请参阅下面的注解）：

set hive.tez.input.format=org.apache.hadoop.hive.ql.io.HiveInputFormat;

set tez.grouping.min-size=16777216; -- files with smaller size will be combined if possible
set tez.grouping.max-size=67108864; -- (default is 1 Gb), files with bigger size will be splitted and more mappers started

您还可以使用此设置控制Map器的数量：

set mapreduce.job.maps=128; --better use grouping splits configuration (above) instead of this one because it is more flexible