Moving Subpartitions to a duplicate table in a different schema.

Question

+NOTE: I asked this question on the PL/SQL and SQL forum, but have moved it here as I think it's more appropriate to this forum. I've placed a pointer to this post on the original post.+
Hello Ladies and Gentlemen.
We're currently involved in an exercise at my workplace where we are in the process of attempting to logically organise our data by global region. For information, our production database is currently at version 10.2.0.3 and will shortly be upgraded to 10.2.0.5.
At the moment, all our data 'lives' in the same schema. We are in the process of producing a proof of concept to migrate this data to identically structured (and named) tables in separate database schemas; each schema to represent a global region.
In our current schema, our data is range-partitioned on date, and then list-partitioned on a column named OFFICE. I want to move the OFFICE subpartitions from one schema into an identically named and structured table in a new schema. The tablespace will remain the same for both identically-named tables across both schemas.
Do any of you have an opinion on the best way to do this? Ideally in the new schema, I'd like to create each new table as an empty table with the appropriate range and list partitions defined. I have been doing some testing in our development environment with the EXCHANGE PARTITION statement, but this requires the destination table to be non-partitioned.
I just wondered if, for partition migration across schemas with the table name and tablespace remaining constant, there is an official "best practice" method of accomplishing such a subpartition move neatly, quickly and elegantly?
Any helpful replies welcome.
Cheers.
James

Answer 1

You CAN exchange a subpartition into another table using a "temporary" (staging) table as an intermediary.
See :
SQL> drop table part_subpart purge;
Table dropped.
SQL> drop table NEW_part_subpart purge;
Table dropped.
SQL> drop table STG_part_subpart purge;
Table dropped.
SQL>
SQL> create table part_subpart(col_1  number not null, col_2 varchar2(30))
  2  partition by range (col_1) subpartition by list (col_2)
  3  (
  4  partition p_1 values less than (10) (subpartition p_1_s_1 values ('A'), subpartition p_1_s_2 values ('B'), subpartition p_1_s_3 values ('C'))
  5  ,
  6  partition p_2 values less than (20) (subpartition p_2_s_1 values ('A'), subpartition p_2_s_2 values ('B'), subpartition p_2_s_3 values ('C'))
  7  )
  8  /
Table created.
SQL>
SQL> create index part_subpart_ndx on part_subpart(col_1) local;
Index created.
SQL>
SQL>
SQL> insert into part_subpart values (1,'A');
1 row created.
SQL> insert into part_subpart values (2,'A');
1 row created.
SQL> insert into part_subpart values (2,'B');
1 row created.
SQL> insert into part_subpart values (2,'B');
1 row created.
SQL> insert into part_subpart values (2,'C');
1 row created.
SQL> insert into part_subpart values (11,'A');
1 row created.
SQL> insert into part_subpart values (11,'C');
1 row created.
SQL>
SQL> commit;
Commit complete.
SQL>
SQL> create table NEW_part_subpart(col_1  number not null, col_2 varchar2(30))
  2  partition by range (col_1) subpartition by list (col_2)
  3  (
  4  partition n_p_1 values less than (10) (subpartition n_p_1_s_1 values ('A'), subpartition n_p_1_s_2 values ('B'), subpartition n_p_1_s_3 values ('C'))
  5  ,
  6  partition n_p_2 values less than (20) (subpartition n_p_2_s_1 values ('A'), subpartition n_p_2_s_2 values ('B'), subpartition n_p_2_s_3 values ('C'))
  7  )
  8  /
Table created.
SQL>
SQL> create table STG_part_subpart(col_1  number not null, col_2 varchar2(30))
  2  /
Table created.
SQL>
SQL> -- ensure that the Staging table is empty
SQL> truncate table STG_part_subpart;
Table truncated.
SQL> -- exchanging a subpart out of part_subpart
SQL> alter table part_subpart exchange subpartition
  2  p_2_s_1 with table STG_part_subpart;
Table altered.
SQL> -- exchanging the subpart into NEW_part_subpart
SQL> alter table NEW_part_subpart exchange subpartition
  2  n_p_2_s_1 with table STG_part_subpart;
Table altered.
SQL>
SQL>
SQL> select * from NEW_part_subpart subpartition (n_p_2_s_1);
     COL_1 COL_2
        11 A
SQL>
SQL> select * from part_subpart subpartition (p_2_s_1);
no rows selected
SQL>I have exchanged subpartition p_2_s_1 out of the table part_subpart into the table NEW_part_subpart -- even with a different name for the subpartition (n_p_2_s_1) if so desired.
NOTE : Since your source and target tables are in different schemas, you will have to move (or copy) the staging table STG_part_subpart from the first schema to the second schema after the first "exchange subpartition" is done. You will have to do this for every subpartition to be exchanged.
Hemant K Chitale
Edited by: Hemant K Chitale on Apr 4, 2011 10:19 AM
Added clarification for cross-schema exchange.