I need a proof based book to study theory of probability and statistics. I have read that one of the best is Mood &amp; Graybill. I just want that it is proof-based, rigurous, and it talks about probability, statistics, and statistical inference.
I know people love to close duplicates so I am not asking for a reference to start learning statistics (as ).   I have a doctorate in mathematics but never learned statistics. What is the shortest route to the equivalent knowledge to a top notch BS statistics degree and how do I measure when I have achieved that.   If a list of books would suffice (assuming I do the exercises lets say), that's terrific. Yes, I expect working out problems to be an implicit part of learning it but I want to fast track as much as realistically possible. I am not looking for an insanely rigorous treatment unless that is part of what statistical majors generally learn.
What is the best indicator in finding out whether a database is utilized or accessed?  I tried index statistics and  based on I/O utilization but none seem to be a good indicator.   Problem: I have a lot of databases on a development environment and due to space issues we are trying to decommission those that are not used without actually messing with the ones that are really needed.