Histograms Are Evil like Chocolate is Evil

Are you using Histograms to describe your data to the Oracle optimizer? Yes, of course you are – even (especially) if you didn’t know it. Did you want to use them? Are they helping you get to the optimal optimization plan, or making life harder for the optimizer? I will explain the benefits and threats associated with histograms, how the new 12.2 histogram types make them more acceptable,
where they are still a threat and how I usually handle them for greatest benefit in large systems.

Full talk from BGOUG in June 2019

Talk in 5 parts from SiOUG in November 2017

 

Video by Timur Akhmadeev at SiOUG 2017