Hi Experts, just came across quite informative blog Anatomy of an SQL Index by Markus Winand https://use-the-index-luke.com/sql/anatomy. I have few doubts as Markus has repeatedly mentioned that "That means that an index is pure redundancy" and "it occupies its own space, it is highly redundant, and it refers to the actual information stored in a different place." . What I understand , he meant the index works on algorithm , hence it repeatedly changes making earlier one redunda I would be thankful if experts clear any gaps in my understanding. Thanks heaps.