Dropping Partitioned Tables

Oracle Database processes a DROP TABLE statement for a partitioned table in the same way that it processes the statement for a nonpartitioned table. One exception is when you use the PURGE keyword.

To avoid running into resource constraints, the DROP TABLE...PURGE statement for a partitioned table drops the table in multiple transactions, where each transaction drops a subset of the partitions or subpartitions and then commits. The table becomes completely dropped at the conclusion of the final transaction. This behavior comes with some changes to the DROP TABLE statement that you should be aware of.

First, if the DROP TABLE...PURGE statement fails, then you can take corrective action, if any, and then reissue the statement. The statement resumes at the point where it failed.

Second, while the DROP TABLE...PURGE statement is in progress, the table is marked as unusable by setting the STATUS column to the value UNUSABLE in the following data dictionary views:

• USER_TABLES, ALL_TABLES, DBA_TABLES

• USER_PART_TABLES, ALL_PART_TABLES, DBA_PART_TABLES

• USER_OBJECT_TABLES, ALL_OBJECT_TABLES, DBA_OBJECT_TABLES

You can list all UNUSABLE partitioned tables by querying the STATUS column of these views.

Queries against other data dictionary views pertaining to partitioning, such as DBA_TAB_PARTITIONS and DBA_TAB_SUBPARTITIONS, exclude rows belonging to an UNUSABLE table. A complete list of these views is available in "Viewing Information About Partitioned Tables and Indexes".

After a table is marked UNUSABLE, the only statement that can be issued against it is another DROP TABLE...PURGE statement, and only if the previous DROP TABLE...PURGE statement failed. Any other statement issued against an UNUSABLE table results in an error. The table remains in the UNUSABLE state until the drop operation is complete.