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Category: Administration

DDL And The Optimizer

Published 2017-01-12 by Kevin Feasel

Grant Fritchey notes that data definition language (DDL) queries do not appear to go through the query optimizer:

We can check whether or not you’re going to get an execution plan for this in two easy ways. You can capture the estimated plan, or run the query and capture the actual plan. Since most of the time, it’s preferable to work with the added runtime information that an actual plan provides, let’s start there. However, if you execute the query above and try to capture an actual plan, you will not get one. So, let’s capture the estimated plan instead. Here’s what we see:

Not much of a plan really.

Read on for that, and start holding your breath for a new execution plans book.

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Quickstats Craziness

Published 2017-01-12 by Kevin Feasel

Lonny Niederstadt takes an in-depth look at the intersection of several features and discusses an issue:

Here’s the Connect Item involved – written by Michael Swart.

Trace flag 2390 can cause large compile time when dealing with filtered indexes. (Active)
https://connect.microsoft.com/SQLServer/feedback/details/2528743/

Huh.  “What does that have to do with clustered columnstore indexes?” you might ask.  No, really, it’d be a personal favor if you *did* ask…

Ask and then read on.  This is the kind of post I’d send to someone wanting to learn how to troubleshoot issues.

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Delay Between Responses

Published 2017-01-12 by Kevin Feasel

Monica Rathbun begins a new challenge by describing the importance of one tiny form control:

When I worked at the Port of Virginia, I was a little less experienced in SQL and didn’t notice this lovely little option. I of course failed to set it. Can anyone guess what happened? YEP, we got low on resources in the wee hours of the morning and SQL kicked off an Error 017-Insufficient Resources. Thousands of emails were generated and caused the Exchange server to go down as well as some other issues that arose because of this. The worst part is that all the emails had to finish processing before we could delete them from the system. I think when all was said and done there was well over 250k messages it created.

She also includes a list of important alerts; just make sure to set the delay.

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Azure Resource Explorer

Published 2017-01-06 by Kevin Feasel

Kenneth Fisher discusses the Azure Resource Explorer:

Now this is just default tab. The GET, PUT tab. Which basically shows you the get command of the resource manager API that calls this information, and if you hit the edit button you can actually change information in the JSON output and issue a PUT command to send it back. I’ll admit up front that this is a bit beyond me as I don’t do API calls and I’m new enough to Azure that I don’t know what I can and can’t change (everything I’ve tried so far hasn’t worked). There are several other tabs, though, including a Powershell one and I’m a bit more familiar with Powershell. In it, you can see some of the Powershell commands associated with the resource manager and this particular object.

Read on for more information.

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Elastic Pool Database Sizes

Published 2017-01-05 by Kevin Feasel

Vincent-Philippe Lauzon looks at how you can size databases with an Azure Elastic Pool:

We can’t change a database maximum size in the portal (as of December 2016).

Using ARM template, it is easy to change the parameter.  Here, let’s simply show how we would change it for an existing database.

Building on the example we gave in a previous article, we can easily grab the Pool-A-Db0 database in resource group DBs and server pooldemoserver:

Click through for all the details.  I highlighted this snippet as another point that the most important language for a Windows administrator to learn nowadays is Powershell.

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Tracking Applications

Published 2017-01-03 by Kevin Feasel

Andy Levy explains how to use connection strings to track which application is hogging database resources:

Fortunately, the .NET SqlClient (and other ODBC drivers as well) has a built-in solution. Your application’s connection string has quite a few parameters available to provide configuration and information, and one that seems to get overlooked is Application Name. This one does exactly what it says on the tin – it lets you specify a name that will be displayed to anyone looking for it in SQL Server, including sp_whoisactive. Anyplace you have the ability to write a connection string, you can use this. It costs you nothing!

You can also start getting fancy with resource governor as well, segmenting pools based on application name.

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Transactional Replication To Azure SQL Database

Published 2016-12-28 by Kevin Feasel

Jes Borland has a five-part series on replicating a series of databases in an Availability Group to Azure SQL Database.  Part 1 involves planning:

There are tasks you’ll need to take care of in SQL Server, the AG, and the SQL DB before you can begin.

This blog series assumes you already have an AG set up – it won’t go through the setup of that. It also assumes you have an Azure SQL server and a SQL Database created – it won’t go through that setup either.

Ideally, the publishers, distributor, and subscribers will all be the same version and edition of SQL Server. If not, you have to configure from the highest-version server, or you will get errors.

Part 2 prepares the replication distributor:

The first step in this process is to set up the remote distributor. As I mentioned in the first blog, you do not want your distribution database on one of the AG replicas. You need to set this up on a server that is not part of the AG.

Start by logging on to the distributor server – in this demo, SQL2014demo.

Stay tuned for the remainder of the series.

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