DSXchange

If the only change is the database version, then 'update query generation' would not have changed, only what Oracle does with them. For what it's worth, we're not using DataStage but had a plethora of new problems crop up when we were 'forced' to upgrade to 12c before it had a chance to <cough> 'mature' much. Still are having issues although our DBA has worked through most of them so far. And IMHO you wouldn't find any locks (as in normal locks) when the jobs fail as deadlocks are a slightly different beast and a self-inflicted wound.

Involve your official support provider. They may have seen this behavior and have some advice or perhaps patches. I'd also suggest moving from "Auto" to something more specific for your partitioning as suggested here.

Ask the DBA if compression was introduced to the database when you went to 12c.

Also check the exact release of both Information Server and Oracle and insure they are compatible.

For example, Oracle 12c, Release 2 is only certified on Information Server 11.7 or higher.

You can check the IIS requirements web page, be sure to check the "notes" icon as it will specify limitations. You can also ask Customer Service if you need additional information.