Disable Parallel Query for CDB_ Views

During my investigation in cdb$view bug I’ve come across the hidden parameter “_px_cdb_view_enabled” which can disable parallel query for cdb_ views. Lets see it in action.

Leave at default and run query over cdb_data_files.

Now lets disable it by setting it to false and see what happens.

As you can see by the different plans the first is using “PX COORDINATOR” while the second isn’t. Parallel query for cdb_ views is disabled via the hidden parameter. Lets run the same test on the CDB$VIEW bug I have opened with oracle and see what we get.

Voila. The bug is gone once parallel query is disable on the cdb_ views.

Note* This hidden parameter is being used for experimental purposes and should only be set with the blessings of Oracle Support.

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