Oracle interval partitions are not created automatically with alter sub-partition template - oracle

Question

I am using oracle 12c Interval partitioning. I have created the range partition with 1 month interval and list sub-partition using a unique identifier (lets say LOGIN_INTFID).
In table DDL I have added the list of sub-partitions that were known to me at the time of table creation. Here is extract of table DDL:
CREATE TABLE TEST
(
UNIQUE_ID NUMBER(9) NOT NULL,
LOGIN_INTFID VARCHAR2(20) NOT NULL,
LOGIN_SEQNO NUMBER(15) NOT NULL,
LOGIN_DATE DATE DEFAULT SYSDATE NOT NULL
)
PARTITION BY RANGE (LOGIN_DATE)
INTERVAL (NUMTOYMINTERVAL(1,'MONTH'))
SUBPARTITION BY LIST (LOGIN_INTFID) SUBPARTITION TEMPLATE (
SUBPARTITION SP1 VALUES ('ABC'),
SUBPARTITION SP2 VALUES ('DEF'),
)
(PARTITION TEST_Y2018M7D1 VALUES LESS
THAN (TO_DATE('2018-07-01 23:59:59', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN')))
;
With this, new partition and sub partitions are created successfully. Later on, I had added one more sub-partition using the following alter command:
ALTER TABLE TEST modify partition SYS_P7068 add subpartition SP3 values ('XYZ');
I have also altered table TEST with the intention that next time when a new partition gets created, this new sub-partition is included in the table automatically:
ALTER TABLE TEST SET SUBPARTITION TEMPLATE (SUBPARTITION SP3 VALUES('XYZ'));
However, this last part is not working as expected. New partitions are not getting created when I am trying to insert data containing XYZ sub partition value. New partitions are getting created only when sub-partition values ABC/DEF are inserted.
What am I doing wrong?

Answer 1

You can't add a new subpartition to a template.
As the documetation states:
You can modify a subpartition template of a composite partitioned table by replacing it with a new subpartition template.
You have to define a new template consisting of the old and new subpartitions.
This will be valid for the partitions not yet created, for existing partition you have to add the subpartitions manually.
Example - after creation of your table you get one partition with two subpartitions
select PARTITION_NAME, SUBPARTITION_NAME,HIGH_VALUE
from user_tab_subpartitions where table_name = 'TEST';
PARTITION_NAME SUBPARTITION_NAME HIGH_VALUE
-------------- ----------------- ----------
TEST_Y2018 TEST_Y2018M7D1_ 'ABC'
TEST_Y2018 TEST_Y2018M7D1_ 'DEF'
Inserting a row adds an other partition with the same two subpartitions:
insert into test (UNIQUE_ID,LOGIN_INTFID,LOGIN_SEQNO,LOGIN_DATE)
values(1,'ABC',1,DATE'2018-08-02');
PARTITION_NAME SUBPARTITION_NAME HIGH_VALUE
-------------- -------------------- ----------
TEST_Y2018 TEST_Y2018M7D1_SP1 'ABC'
TEST_Y2018 TEST_Y2018M7D1_SP2 'DEF'
SYS_P14654 SYS_SUBP14652 'ABC'
SYS_P14654 SYS_SUBP14653 'DEF'
Now you change the subpartition template - by defining all the new subspartitions
ALTER TABLE TEST SET SUBPARTITION TEMPLATE (
SUBPARTITION SP1 VALUES ('ABC'),
SUBPARTITION SP2 VALUES ('DEF'),
SUBPARTITION SP3 VALUES('XYZ'));
and adds an other row
insert into test (UNIQUE_ID,LOGIN_INTFID,LOGIN_SEQNO,LOGIN_DATE)
values(1,'ABC',1,DATE'2018-09-02');
The new partition has now as expected three subpartitions
PARTITION_NAME SUBPARTITION_NAME HIGH_VALUE
-------------- -------------------- ----------
TEST_Y2018 TEST_Y2018M7D1_SP1 'ABC'
TEST_Y2018 TEST_Y2018M7D1_SP2 'DEF'
SYS_P14654 SYS_SUBP14652 'ABC'
SYS_P14654 SYS_SUBP14653 'DEF'
SYS_P14658 SYS_SUBP14655 'ABC'
SYS_P14658 SYS_SUBP14656 'DEF'
SYS_P14658 SYS_SUBP14657 'XYZ'