Marcia J (12/7/2015)
Hugo, I'm wondering if there is an article you would recommend on the different operators and how they affect performance.
Unfortunately, there is not much out there. When I prepared the content for a full-day training on this subject (that I have delivered as a precon a few times now, and hopefully will again in the future), I sometimes found some bits and pieces by googling names of individual operators, combining all I could find and trying to distinguish between fact, good speculation, bad speculation, and downright nonsense.
I am currently converting my precon material to a Pluralsight course, but that is a slow process so I cannot point you there yet. Expect at least several months to pass before that course sees the light of day, I have to juggle time between day job, family, and several side projects of which Pluralsight is just one.
Red Gate publishing has a book by Grant Fritchey (https://www.red-gate.com/community/books/sql-server-execution-plans-ed-2). You can download the PDF version for free, and the print copy won't cost you an arm and a leg. However, if you want to buy a physical copy, I recommend waiting for the third edition - and if you download I recommend downloading again once the third edition is out. Grant has made a lot of improvements that make the book much better than it already was, and hopefully it will get even better once I am done reviewing it (I am the tech editor for that book - one of those side projects). Do not expect an operator by operator approach in that book, that's not Grant's style. But you'll still learn a lot.
I hope this helps aat least as a starting point.