Production Database Administration

Ten Ways to Set MAXDOP

Configuration Settings
Whenever I work with SQL Server, I’m amazed at how many ways there are to influence its behavior. For example, take the maximum degree of parallelism for a query. Just offhand, I thought of ten different ways you can tweak it: 1. At the server level with SSMS. In SSMS, right-click on the server, click Properties, Advanced,…
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Availability Groups: More Planned Downtime for Less Unplanned Downtime

I often hear companies say, “We can never ever go down, so we’d like to implement Always On Availability Groups.” Let’s say on January 1, 2016, you rolled out a new Availability Group on SQL Server 2014. It’s the most current version available at the time, and you deploy Service Pack 1, Cumulative Update 4 (released…
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The Law Of The Minimum

I like science fiction Not enough to go to conventions, or memorize every line, but I have some opinions on things. Dune is probably my favorite series of stories in the genre. Yes, I think Paul would beat Luke in a fight. Sorry, Star Wars people. He’s just kind of a wimp. Throw grenade, digress One…
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Breaking News: 2016 Query Store cleanup doesn’t work on Standard or Express Editions

If you’re using SQL Server 2016’s awesome new feature, Query Store, there’s a new bug with automatic cleanup. Books Online explains: Automatic data cleanup fails on editions other than Enterprise and Developer. Consequently, space used by the Query Store will grow over time until configured limit is reached, if data is not purged manually. If…
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Is your SAN’s cache killing tempdb?

SQL Server, Storage, TempDB
Let’s start with definitions Many SANs have caching built in. What kind of cache is important, because if you’re dealing with non-SSD storage underneath, you could be waiting for a really long time for it to respond. Let’s start with some definitions of the most popular caching mechanisms available for SANs. I’m not going to…
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Creating Tables and Stored Procedures in TempDB – Permanently

No, not #tables – actual tables. Here’s how: USE tempdb; GO /* This one is only available during my session: */ CREATE TABLE #myTempTable (ID INT IDENTITY(1,1), Stuffing VARCHAR(100)); GO /* This one is global, meaning it's available to other sessions: */ CREATE TABLE ##myTempTable (ID INT IDENTITY(1,1), Stuffing VARCHAR(100)); GO /* You can create…
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Breaking News, Literally: SQL CLR Support Removed from Azure SQL DB

Breaking News, Microsoft Azure
In the on-premises, boxed-product version of SQL Server, you can build your own CLR assemblies and call them from your T-SQL code. For years, this feature was missing from Azure SQL DB – Microsoft’s platform-as-a-service database offering – and users voted that they wanted it. In December 2014, Microsoft brought SQL CLR code to Azure SQL…
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When Shrinking Tempdb Just Won’t Shrink

SQL Server, TempDB
I am not a proponent of shrinking databases, but sometimes you have to because your momma said to. Sometimes that database is tempdb. It used to be that we were warned against shrinking tempdb because it could cause corruption, so your only recourse was to restart the SQL Server service. Paul Randal let us know…
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“Breaking” News: Don’t Install SQL Server 2014 SP1

Yesterday, Microsoft announced availability of Service Pack 1, saying: As part of our continued commitment to software excellence for our customers, this upgrade is available to all customers with existing SQL Server 2014 deployments via the download links below. Yeah, about that commitment to software excellence. This morning, the download is gone: Notice: The SQL SSIS…
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The Hard Truth About Patching SQL Server Availability Groups (Hotfixes, Cumulative Updates, and Service Packs)

Whoa, be careful with that fix As a DBA, you’re responsible for identifying necessary updates to keep your SQL Servers healthy. Your business may have some mandates about the frequency of patches, but even if they don’t, you have a duty to look out for Cumulative Updates, Service Packs, and out of band hotfixes that can prevent…
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