About Parallel DML Operations

Parallel DML (PARALLEL INSERT, UPDATE, DELETE, and MERGE) uses parallel execution mechanisms to speed up or scale up large DML operations against large database tables and indexes.

Note:

Although DML generally includes queries, in this chapter the term DML refers only to INSERT, UPDATE, MERGE, and DELETE operations.

This section discusses the following parallel DML topics:

When to Use Parallel DML
Enable Parallel DML Mode
Rules for UPDATE_ MERGE_ and DELETE
Rules for INSERT SELECT
Transaction Restrictions for Parallel DML
Rollback Segments
Recovery for Parallel DML
Space Considerations for Parallel DML
Restrictions on Parallel DML
Data Integrity Restrictions
Trigger Restrictions
Distributed Transaction Restrictions
Examples of Distributed Transaction Parallelization
Concurrent Execution of Union All