A recent “Hot topics” email from Oracle support listed the following bug as one which had recently been updated:
17727676 OPTIMIZER HINT IGNORED WHEN USING INVISIBLE INDEXES
Since the optimizer is one of my pet topics I thought I’d take a quick look at what it said – and found this heart-warming introduction;
Hdr: 17727676 126.96.36.199.0 RDBMS 188.8.131.52.0 QRY OPTIMIZER PRODID-5 PORTID-226 Abstract: OPTIMIZER HINT IGNORED WHEN USING INVISIBLE INDEXES *** 11/03/13 03:46 am *** PROBLEM: -------- Based on a blog article from the international recognized Oracle Expert Jonathan Lewis ...
If it’s on MoS surely it’s just got to be true! (Yes, I know I’ve said the opposite in the past – but it’s definitely right some of the time)
The bug/blog in question was this one, and the problem is fixed in 12.2