Intra-partition parallelism for
DELETE operations require that the
COMPATIBLE initialization parameter be set to 9.2 or greater.
VALUES statement is never executed in parallel.
A transaction can contain multiple parallel DML statements that modify different tables, but after a parallel DML statement modifies a table, no subsequent serial or parallel statement (DML or query) can access the same table again in that transaction.
This restriction also exists after a serial direct-path
INSERT statement: no subsequent SQL statement (DML or query) can access the modified table during that transaction.
Queries that access the same table are allowed before a parallel DML or direct-path
INSERT statement, but not after.
Any serial or parallel statements attempting to access a table that has been modified by a parallel
MERGE, or a direct-path
INSERT during the same transaction are rejected with an error message.
Parallel DML cannot occur in the presence of certain constraints: self-referential integrity, delete cascade, and deferred integrity. In addition, for direct-path
INSERT, there is no support for any referential integrity.
For non-partitioned tables with LOB columns, parallel
INSERT operations are supported provided that the LOB columns are declared as SecureFiles LOBs. Parallel
MERGE operations on such tables are not supported.
A DML operation cannot be executed in parallel if it is in a distributed transaction or if the DML or the query operation is on a remote object.
Clustered tables are not supported.
MERGE operations are not supported for temporary tables.
Parallel DML is not supported on a table with bitmap indexes if the table is not partitioned.
Violations of these restrictions cause the statement to execute serially without warnings or error messages (except for the restriction on statements accessing the same table in a transaction, which can cause error messages).
You can only update the partitioning key of a partitioned table to a new value if the update does not cause the row to move to a new partition. The update is possible if the table is defined with the row movement clause enabled.
The function restrictions for parallel DML are the same as those for parallel DDL and parallel query. See "About Parallel Execution of Functions" for more information.