Archives for: "November 2010"

Multiple statistics sharing the same leading column

SQL Server will not prevent you from creating identical indexes or statistics. You may think that everything is under your control, but have you ever added a missing index that has been reported by the query optimizer, or the DTA? If so, you will… mehr »

Did you know: Aggregate functions on floats may be non-deterministic

One day some of the report-users mentioned that, every time they run a report, they get different results. My first idea was that there were some undergoing data changes, probably from a different connection/user, so this would explain it. But it turned… mehr »

No automatically created or updated statistics for read-only databases

Ok, that's not really the latest news and also well documented. But keep in mind that database snapshots also fall into the category of read-only databases, so you won't see automatically maintained statistics for these as well. I've seen the advice of… mehr »