But thanks be to God, who always leads us as captives in Christ’s triumphal procession and uses us to spread the aroma of the knowledge of him everywhere. For we are to God the pleasing aroma of Christ among those who are being saved and those who are perishing. To the one we are an aroma that brings death; to the other, an aroma that brings life. And who is equal to such a task?
Me? I'm a mess. This blog is a mess. Half of the links don't work because I spend so much time fretting over how to create my own theme - only to find that the finished product doesn't really fit the needs I didn't realize I have. Additionally, I've misconfigured something in the "front-matter" such that the static site generator doesn't detect the post content. Some people may say that I should just stick with a known quantity, like WordPress.
I am speaking on statistics in June at the Denver SQL Server User Group but didn’t really want to rehash much of the same old information that I’ve heard in the past. There’s a wealth of information about how to interpret stat headers, density vectors, and histograms. There’s also been plenty of virtual ink spilled on when statistics are updated (if you have auto update enabled).
One new(ish, to me) and interesting topic I stumbled across is the notion of temporary statistics.
Recently, our index maintenance process was called into question on an Availability Group because it began running significantly longer than expected. The initial theory put forward by other groups was that this was due the Availability Group which is a 2+1 cluster (2 HA synchronous replicas, 1 asynchronous DR replica) and there was a commit delay. Our monitoring tool SentryONE didn’t alert us to any significant delays, but we committed to investigate the theory since it would be a good exercise for all involved.
Previously, we looked at analyzing a table to see which columns in that table may contain skewed data.
That was a good start, but now it’s time to look at the statistics that exist on that column to see if we can identify potential candidates for filtered statistics, based on the “windows” between histogram steps.
Much of the logic is the same in this script, except it counts every value in the column.
While in the process of looking for a job that led to the position that I currently hold, I interviewed for a job at a recognizably-named company that was struggling to keep up with their “statistics.” I have a confession. I had no idea what “statistics” were in the SQL Server world. I wasn’t offered that job, but in the interim I did a lot of reading and research on the SQL Server notion of “statistics.
Previously, I did a little investigation into incremental statistics and what benefit they can provide. The goal was to find the intersection of update timings for incremental and non-incremental statistics, with the hope of being able to demonstrate a reclamation of statistics maintenance times - and perhaps higher sample rates. Summary: we can, and auto_stats is a beneficiary. However, is this a solution in search of a problem? If you’ve been bumping into statistics maintenance issues, you’re probably already familiar with more of the hands-on intervention available (my personal favorite is Ola Hallengren’s solution).
I originally created this post and observed some rather embarrassing sloppiness and miscalculations. I’ve simply decided to pull the post and rework it. This is the result of those labors.
Recently, I answered a question on dba.stackexchange related to an interesting occurrence with incremental statistics. This led to an good conversation about the efficacy (and utility) of incremental statistics. The primary focus was on Erin Stellato’s confirmation that partition-level stats are not used by the Query Optimizer, thereby identifying a rather sizable gap in the utility of incremental statistics.
As I was sitting in Bob Ward’s Inside SQL Server I/O presentation, something interesting caught my eye on a slide that noted that ReFS is now supported for SQL Server 2014. I’d run into problems with 2012 so I’d just given up but this looks promising. I am neither a filesystem aficionado, nor a dilettante but I know that there are some interesting features of ReFS at which Windows server admins are looking to see if it’s viable.
As I was sitting in Bob Ward’s Inside SQL Server I/O presentation, something interesting caught my eye on a particular slide.
It looks like ReFS is now supported for SQL Server 2014. I’d run into problems with 2012 so I’d just given up but this looks promising. I am neither a filesystem aficionado, nor a dilettante but I know that there are some interesting features of ReFS at which Windows server admins are looking to see if it’s viable.