Hudi merge into creates empty partition files when the source table has partitions and the target table does not

 
--source table
create table hudi_test_wm_mor_01 (
  id int,
  name string,
  price double,
  ts bigint,
  dt string
) using hudi
tblproperties (
  type = 'mor',
  primaryKey = 'id',
  preCombineField = 'ts'
)
partitioned by (dt);
 
 
--target table
create table hudi_test_wm_mor_02 (
  id int,
  name string,
  price double,
  ts bigint,
  dt string
) using hudi
tblproperties (
  type = 'mor',
  primaryKey = 'id',
  preCombineField = 'ts'
)
partitioned by (dt);
 
– insert some data
insert into hudi_test_wm_mor_01 (id,name,price,ts,dt) values (12,'a12',23.234,1648871782,'2021-12-11');
insert into hudi_test_wm_mor_01 (id,name,price,ts,dt) values (13,'a13',24.234,1648871783,'2021-12-12');
insert into hudi_test_wm_mor_01 (id,name,price,ts,dt) values (14,'a14',25.234,1648871784,'2021-12-13');
insert into hudi_test_wm_mor_01 (id,name,price,ts,dt) values (15,'a15',26.234,1648871785,'2021-12-14');
insert into hudi_test_wm_mor_01 (id,name,price,ts,dt) values (16,'a16',27.234,1648871786,'2021-12-15');
{}{}
 
insert into hudi_test_wm_mor_02 (id,name,price,ts,dt) values (12,'target12',88.1,1648871782,'2021-12-11');
insert into hudi_test_wm_mor_02 (id,name,price,ts,dt) values (13,'target13',89.1,1648871783,'2021-12-12');
 
 
--merge operation
merge into hudi_test_wm_mor_02 h0
using (
 select id, name, price, ts, dt from hudi_test_wm_mor_01
 ) s0
 on h0.id = s0.id and h0.dt = s0.dt
 when matched then update set * ;
 

Description:

After the merge sql executes, five partitions are created in the target table (2021-12-11, 2021-12-12, 2021-12-13, 2021-12-14, 2021-12-15).

Actually only two partitions of the data match, creating two partitions as expected (2021-12-11, 2021-12-12)

The remaining 3 partitions should not be created (2021-12-13, 2021-12-14, 2021-12-15).

In extreme cases, a very large number of empty partitions are created in the target table