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Category: Administration

Undocumented Commands Can Change

Published 2019-07-29 by Kevin Feasel

Thomas Rushton warns us that undocumented commands in SQL Server are liable to change without notice:

I don’t have every version available to test, but it does appear that the record indicating Containment State is mis-spelled in SQL Server 2012 as “dbi_ContianmentState”, and then corrected in SQL 2014 and later. It’s a good job I’m not relying on it for anything.

So, yes, don’t rely on undocumented functions – as they may change without notice.

If there’s a documented method, use that one. If the only method available is undocumented, you can still use it, but be sure to test it with each release—that is, major release, service pack, or cumulative update.

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Automated Alert Emails

Published 2019-07-29 by Kevin Feasel

Max Vernon shows how you can use the SQL Server Agent to send automated e-mails on alerts:

SQL Server Agent provides a great mechanism for sending alerts via email in response to various events. Once you’ve setup Database Mail, and configured a SQL Server Agent Operator, you should add alerts for severe errors that affect the health of your SQL Server. Creating Alerts can be tedious, but automating Alerts is simple, with the easy code below that automates creating alerts in response to critical events. Automating alerts is important because it provides a standardized Alert configuration that can be used by all the SQL Servers in your organization.

Read on for the script.

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Why Transaction Logs are Zero-Initialized

Published 2019-07-25 by Kevin Feasel

Paul Randal explains why the transaction log needs to be zero-initialized before SQL Server starts up:

It’s all to do with crash recovery. SQL Server knows where crash recovery has to start for a database, but not where it ends – i.e. SQL Server does not persist the ‘most recent LSN’ for a database anywhere. This means it has to work out where the end of the log is (and by end, I mean the most recent log record persisted on disk, not the physical end of the log file).

Read on for the detailed explanation.

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Azul Java in SQL Server 2019

Published 2019-07-25 by Kevin Feasel

Travis Wright announces support for Azul Systems’ Java distribution in SQL Server 2019:

In September 2018, Microsoft announced a new partnership with Azul Systems, a leading Java open source contributor and distributor. This partnership allows for all Azure customers to use Azul’s Zulu for Azure – Enterprise distribution of Java for free with support jointly provided by Microsoft and Azul. That’s right – supported for free.

Today, we are announcing that we have extended that partnership to cover SQL Server. Starting in the SQL Server 2019 community technology preview (CTP) 3.2 that was released today, we are including Azul System’s Zulu Embedded right out of the box for all scenarios where Java is used in SQL Server – in PolyBase, Apache Spark, Java extensibility, and more. There is no additional cost beyond what you pay for SQL Server.

This is interesting. We’ll have to see if the CTP 3.2 installation doesn’t ask for JDK 1.8 anymore and just installs the Azul Systems version.

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When tempdb Spills Attack

Published 2019-07-23 by Kevin Feasel

Josh Darnell ran into a problem with a SQL Agent job:

One of my colleagues reached out to me recently about a production issue where a SQL Server Agent job had failed with this error message:

Msg 1105, Level 17, State 2, Line 15
Could not allocate space for object ‘dbo.SORT temporary run storage: 140737513062400’ in database ‘tempdb’ because the ‘PRIMARY’ filegroup is full. Create disk space by deleting unneeded files, dropping objects in the filegroup, adding additional files to the filegroup, or setting autogrowth on for existing files in the filegroup.

I fully expected this to be a scheduled maintenance task, like index rebuilds or statistics updates. I’ve seen this error before in those contexts (rebuilding large indexes in tempdb, or updating statistics with FULLSCAN).

But watch as SQL Server subverts Josh’s expectations.

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Multi-Server Patching with dbatools

Published 2019-07-22 by Kevin Feasel

Eric Cobb shows how you can use dbatools to upgrade multiple SQL Server instances:

Patching SQL Server can sometimes be a time consuming process, especially when you have multiple servers that need to be patched. Remoting in to each box to run through the update wizard is tedious, and if you have multiple patches to apply you’re going to be spending a considerable chunk of time on it.

Thankfully, the dbatool Powershell Module makes this process much easier! In fact, once you get it figured out, using Update-DbaInstance to patch your SQL Servers becomes very simple. But, getting it figured out can be a little confusing, so I’ve outlined the steps below that I use. The biggest hangups I had were setting up a central patching location and using a credential to access it.

Click through to see an example of this in action.

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Changes to Azure SQL Database SLA

Published 2019-07-19 by Kevin Feasel

Arun Sirpal notes a change to the Azure SQL Database Service Level Agreement:

I am sure many missed the updates to Azure SQL Database SLA (Service Level Agreement). It used to be 99.99% across all tiers  but split between two different high-availability architectural models. Basic, Standard and General Purpose tiers had its own model and the Premium / Business Critical tiers had a different one.

Read on to see the change.

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Disk Utilization Per Drive in SQL Server

Published 2019-07-19 by Kevin Feasel

Max Vernon has a script which shows more than what xp_fixeddrives has to offer:

However, the command output doesn’t include the total size of each drive, making it impossible to determine the percent free space. If you’re in an environment where a separate team monitors disk space, and has alerts set when free space falls below a certain percentage, you may want to ensure you don’t breach those levels. The following script provides “the big picture” for your servers, since it provides total size, free space, available space, and the percent free. It does require the use of the documented and supported sys.xp_cmdshell system extended stored procedure. The code uses the drive letters returned by sys.xp_fixeddrives inside a cursor. Inside the cursor, we call the dos command fsutil volume diskfree C: to get total capacity and free space, etc:

Click through for the script.

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Notifications when Admins Connect to a SQL Server

Published 2019-07-12 by Kevin Feasel

Jon Shaulis builds a logon trigger to notify when sysadmins log into his systems:

I was helping someone set up some monitoring in their database and they were asking about being notified when someone with administrative privileges logs into SQL Server. While many of you know that I try to use the right tool for the right job, some may cringe when I say triggers can help out in this scenario.

Now, there are other methods here but the goal was to be notified when someone logs into your SQL Server with administrative privileges. Triggers will consistently fire when this event occurs and allows you to perform an action based on this event.

Just make sure you get the trigger right and don’t block everybody from logging in. That’s an awkward situation.

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Memory Defaults in SQL Server 2019

Published 2019-07-11 by Kevin Feasel

Randolph West looks at a new settings tab in the SQL Server 2019 installation:

In 2016 I created the Max Server Memory Matrix as a guide for configuring the maximum amount of memory that should be assigned to SQL Server, using an algorithm developed by Jonathan Kehayias.

SQL Server 2019 is still in preview as I write this, but I wanted to point out a new feature that Microsoft has added to SQL Server Setup, on the Windows version.

On the Database Engine Configuration screen are two new tabs, called MaxDOP and Memory. These are both new configuration options for SQL Server 2019. Last week we looked at MaxDOP, and this post will specifically look at the Memory tab.

It’s a small change but a nice one.

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