Re: Query Performance with params

  • From: Mladen Gogala <gogala.mladen@xxxxxxxxx>
  • To: Thomas Roach <troach@xxxxxxxxx>
  • Date: Sun, 30 Apr 2017 13:04:54 -0400

On 04/30/2017 12:42 PM, Thomas Roach wrote:

If it's 12.1, then if you are going to set any parameter outside of defaults, it would be optimizer_features_enable back to That's usually when people throw in the towel if they can't figure it out otherwise.

That will not do much for you. OFE will set up some constants to their values, but the optimizer code will still be the code from version 12. There are no shortcuts. My usual advice to the customers is to wait for the first major patch set of the version 12.2 to upgrade and not to upgrade to 12.1. The optimizer in 12.1 is almost completely rewritten, there are bound to be some bugs. Those bugs usually get polished in the second edition. That was the case with 11.1, although was almost unusable. Somebody on this group has even recently called a "buggy cesspool". The new versions are so complex and have so many interacting features that it has become extremely hard to write something that will not be buggy.

Mladen Gogala
Oracle DBA
Tel: (347) 321-1217

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