Development

Buskets Much like Sorts, Hash Joins require some amount of memory to operate efficiently  — without spilling, or spilling too much. And to a similar degree, the number of rows and columns passed to the Hashing operator matter where the memory grant is concerned. This doesn’t mean Hashing is bad, but you may need to…

Like Table Variables, Kinda Jeremiah wrote about them a few years ago. I always get asked about them while poking fun at Table Variables, so I thought I’d provide some detail and a post to point people to. There are some interesting differences between them, namely around how cardinality is estimated in different situations. Table…

sp_prepare For Mediocre You may remember me from movies like Optimize for… Mediocre? and Why You’re Tuning Stored Procedures Wrong (the Problem with Local Variables)! Great posts, Kendra! Following the same theme, we found this issue while looking at queries issued from JDBC. Specifically, the prepared statement class seems to cause queries to hit the density vector…

FREAK OUT You wrote a query. You joined tables. You have the right ON clause. You have the right WHERE clause. But the query plan has a problem! BugBurg How Could This Happen To Me? Oh, relax. You’re not crazy. You just assumed the worst. Like me whenever I feel pain near my liver. Call…

In part 1 of this series, I showed you how to get the compiled parameter values for an execution plan that you are investigating. You’ve identified it as a bad execution plan. You’ve already fixed the production emergency by removing the bad plan from the plan cache. You’re almost ready to start testing for a…

Many of you are troubleshooting Parameter Sniffing issues the wrong way in production. In this three-part series, I’ll show you how to troubleshoot it the right way: Getting the Compiled Parameter Values Getting the App’s SET Options Avoiding the Density Vector This is part 1 in the series. Parameter Sniffing 101 When a query suddenly…