keep it fresh. keep it fun
Occasionally we do as we are told. And when Brent Ozar tells us that we should celebrate the first T-SQL Tuesday of 2017 by writing about SQL Server bugs and enhancement requests, the only appropriate response is “What color, sir?”
Continue reading “#TSQL2SDAY: Sing a song of unsigned ints”
While researching my previous post on latch promotion, I came across an odd piece of magic that made me do a double take. And sleep on it. And tear out my hair. I took it on faith that this is more likely a clever algorithm than a brain fart, but I could not stop asking myself repeatedly…
The piece of code in question is really simple, involving the maintenance of the BUF structure’s breferences member, which notionally is a count of how many times the page has been touched since the page’s counters were last reset.
Continue reading “How SQL Server counts page refs without counting”
It’s not often that bit-twiddling and SQL sit well together. Different sides of the railway line and all that. However, I recently came across an interesting expression which fits the bill:
f(n) = ~n & ~(n-1)
Or in something closer to English:
f(n) = NOT n AND (NOT (n - 1))