This is not a datapump issue but a loading issue - an empty partition gets a fresh segment and hence a valid index
SQL> create table t
2 partition by range( created )
3 interval( numtoyminterval(1,'month'))
4 ( partition p2010 values less than ( to_date('01-Jan-2011','dd-mon-yyyy') ) )
5 as
6 select * from all_objects
7 where 1 = 0 ;
Table created.
SQL> create index t_idx on t( owner,object_type ) local unusable;
Index created.
SQL> insert /*+ APPEND */ into t
2 select * from all_objects;
77436 rows created.
SQL> commit;
Commit complete.
SQL> col partition_name for a10
SQL> select partition_name,status
2 from user_ind_partitions
3 where index_name ='T_IDX';
PARTITION_ STATUS
---------- --------
P2010 UNUSABLE
SYS_P18386 USABLE
SYS_P18387 USABLE
SYS_P18388 USABLE
SYS_P18389 USABLE
SYS_P18390 USABLE
SYS_P18391 USABLE
SYS_P18392 USABLE
SYS_P18393 USABLE
SYS_P18394 USABLE
SYS_P18395 USABLE
SYS_P18396 USABLE
SYS_P18397 USABLE
SYS_P18398 USABLE
SYS_P18399 USABLE
SYS_P18400 USABLE
SYS_P18401 USABLE
SYS_P18402 USABLE
SYS_P18403 USABLE
SYS_P18404 USABLE
SYS_P18405 USABLE
SYS_P18406 USABLE
22 rows selected.
You;ll be better off creating the index after the load.
I'll ask around internally for what other options are possible
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Addenda
You can get around this with partial indexing, eg
SQL> create table t ( x int, y int )
2 partition by range ( x )
3 interval ( 10 )
4 (
5 partition p1 values less than ( 2 )
6 ) indexing off;
Table created.
SQL>
SQL> create index t_idx on t ( x ) local unusable indexing partial;
Index created.
SQL>
SQL> col partition_name for a10
SQL> select partition_name,status
2 from user_ind_partitions
3 where index_name ='T_IDX';
PARTITION_ STATUS
---------- --------
P1 UNUSABLE
1 row selected.
SQL> insert into t values (4,4);
1 row created.
SQL> insert into t values (40,40);
1 row created.
SQL> col partition_name for a10
SQL> select partition_name,status
2 from user_ind_partitions
3 where index_name ='T_IDX';
PARTITION_ STATUS
---------- --------
P1 UNUSABLE
SYS_P18439 UNUSABLE
SYS_P18440 UNUSABLE
3 rows selected.
then set indexing back to full and do your rebuild as you like