![]() ![]() This is being run on 2014, so we don’t expect the dynamic threshold stuff. One may posit, then, that they could let their workloads run wild and free, and that SQL would dutifully track modifications, and trigger automatic updates when necessary. They both have non-unique nonclustered indexes on DateFiller, TextFiller.Nuisance2 has the clustered PK on ID, DateFiller.It will show 1,000,000 rows sampled, and no modifications, and the last stats update column will have a date in it. If we go back to our DMV query, the stats columns will at least not be NULL now. It has a non-unique, nonclustered index on DateFiller and TextFiller. Table 1 has a clustered PK on the ID column. It’s the only way to really show you how weird it gets inside SQL’s head. We’re gonna need a couple tablesīut they’ll be slightly different. And that something was how SQL tracks modifications to unique indexes. I’m still going to write about the 2016 stuff, but I caught something weird when I was working on a way to demonstrate those thresholds. Ever try waiting for statistics to automatically update on a billion row table? You’re gonna need a crate of Snickers bars. Anyone who has taken a bite out of a terabyte database probably knows about this one. I got unnaturally excited about this, because it sounds like the behavior of Trace Flag 2371. As of CTP 3.3, we have refined the algorithm such that it is no longer a fixed threshold, but in general will be more aggressive in triggering statistics scans, resulting in more accurate query plans. Previously, statistics were automatically recalculated when the change exceeded a fixed threshold. They’re so cool! Do they get fragmented? NO! Stop trying to defragment them, you little monkey. The blurb in question is about statistics. This started off with me reading a blurb in the release notes about SQL Server 2016 CTP 3.3.
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