Oracle 12.2 has changed the patches. It used to be so easy back in the day. Just download the Cumulative Patch Update (CPU) and apply the latest/greatest security patches. Then Oracle decided security patches were not enough so they gave us the Patch Set Update (PSU) which contained the regression fixes on top of plugging security holes. The CPU was renamed to be the Security Patch Update (SPU) which in my opinion contributed to some monkey business.
Now I’ve always been of the opinion to introduce as little change as possible to a stable production environment. I do need to patch security holes but if I’m not experiencing any other issues, why apply extra patches on top? With the PSU/SPU choice, I always chose the SPU. Oracle’s recommendation was to apply the PSU and beginning with 12.1, the SPU was no longer available.
At some point, Oracle also introduced the Bundle Patch (BP) which contains all of the changes in the PSU plus even more changes for optimizer fixes and functional fixes. Given a choice between SPU, PSU and BP, I’d still choose the SPU if that option were available to me. Oracle now recommends the BP.
Well if that were not confusing enough (remember when it was simple with just the CPU?), Oracle now has the Release Update (RU) and Release Update Revision (RUR). The PSU is gone. I haven’t heard yet, but I suspect the BP is on its way out since the RU covers it.
So what is the RU and RUR? Rather than try to describe it and totally botch the description, I’ll refer you to this blog post by Oracle’s Mike Dietrich. Please give it a read. It does a very nice job detailing the history of what is in the PSU, BP, RU, and RUR. I had to read this post a few times before I got it all sorted out in my head.
That being said, Oracle seems to be making this even more complicated. I know have to understand that the RUR is released the quarter after the RU it modifies. and if I’m reading the last diagram correctly, it means in one quarter, RU1 is released. In the second quarter, RU2 and RUR1 for RU1 is released. And in the third quarter, RU3 is released along with RUR2 for RU1 and RUR1 for RU2. Seems confusing to me. It should be simpler than this. I’m sure Oracle will tell me to keep it simple by applying the RU’s and never worry about the RUR. But again…that introduces more change to a stable production system that I may not be comfortable with.