Reading Execution Plans for Parallel DML

Parallel execution in Oracle seems to be a topic of myths, mysteries and misunderstandings. In this post I hope to clear up at least one of them by diving into a discussion about parallel DML. Actually, I want to show you two things that can go wrong with it.

My demo setup and case are pretty simple, I just create two copies of dba_objects:

SQL> create table a as select * from dba_objects;

Table created.