set hive.exec.dynamic.partition=true;
set hive.exec.dynamic.partition.mode=nonstrict;
set hive.exec.dynamic.partitions.pernode=50000;
set hive.exec.dynamic.partitions.partitions=50000;
set hive.exec.max.created.files=500000;
set mapred.reduce.tasks =20000;
set hive.merge.mapfiles=true;
drop table testpart;
create table testpart(
col1 string,col2 string)
partitioned by (col3 string);
alter table testpart drop partition (col3 ='a');
alter table testpart add partition (col3 ='a');
desc testpart;
show partitions testpart;