October 31, 2017
For any of you who’ve struggled trying to tweak degrees of parallelism (DoP) and affinity masks in multi-core SQL Servers to chop down query times, I have some good news and some bad news.
The bad news first: your well-intentioned attempts are being defeated by an insidious collection of choke points outside of your control that afflict I/O-intensive workloads, OLTP in particular. The good news: these choke points have recently been isolated.
Seasoned practitioners may be thinking, “nothing novel here, we’ve known storage to be the culprit for years.” And while that’s one sure place to look, that’s not where I’m going with this.
Read the entire article here, Black Holes – Casting shadows on SQL Server Parallelism
Via the fine folks at DataCore Software.