I have noticed differences in executions between data pump imports lately, and I am trying to determine what is causing the differences. I am using impdp to move data between databases, and remap the schemas. It seems like I have seen two different things happen when I run the import in parallel, and I am not sure what is causing the differences.
Sometimes I see the job running and it is importing a bunch of tables side by side, other times the import process is only importing a few tables at a time, but using parallel inserts for each table. Using Parallel inserts on just a few tables at a time seems to cut my overall run time substantially, but I can't figure out why it only runs like that sometimes and not others.