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Category: Administration

Trying Query Parameterization Settings in SQL Server

Published 2023-05-01 by Kevin Feasel

Tibor Karaszi builds a test:

You have probably seen the recommendation to turn on the “optimize for ad-hoc workloads” setting. You might even have seen a more recent recommendation to set the database setting parameterization to forced (instead of the default which is simple). The aim of this post is to briefly describe each and then do some test with various settings.

Click through for that test. This is a good example of how we need to temper guidance with context. In Tibor’s scenario, forced parameterization is a no-brainer and optimize for ad hoc workloads gives a pretty nice reduction in plan cache utilization. But then, with optimize for ad hoc workloads on, you lose the ability to see the first run of a query in Query Store and lose the opportunity to tune the different variations of a query which only ran once. Pretty much every setting in SQL Server exists because there is a scenario in which that is the most appropriate setting. Except auto-shrink. Auto-shrink delenda est.

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Removing a Node from Elasticsearch

Published 2023-04-26 by Kevin Feasel

The Big Data in Real World team spams the delete button:

Shutting down a node abruptly is not the right way to decommission or remove a node from the Elasticsearch cluster. Doing so will cause your shards which are replicated to go down in replication and it could cause disruption to the clients who are currently consuming data from Elasticsearch.

Proper way to decommission or remove a node from Elasticsearch is to add the host to the exclusion list.

Click through to learn how to do this.

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9 Gotchas Working with Postgres

Published 2023-04-26 by Kevin Feasel

Phil Booth categorizes various mistakes as learning experiences:

Previously on Extreme Learning, I discussed all the ways I’ve broken production using healthchecks. In this post I’ll do the same for PostgreSQL.

The common thread linking most of these gotchas is scalability. They’re things that won’t affect you while your database is small. But if one day you want your database not to be small, it pays to think about them in advance. Otherwise they’ll came back and bite you later, potentially when it’s least convenient. Plus in many cases it’s less work to do the right thing from the start, than it is to change a working system to do the right thing later on.

Click through for the nine lessons learned, eight of which are still relevant as of PostgreSQL version 12. Many of these also have analogues in the SQL Server world, e.g., don’t overuse triggers, use non-recursive methods for path traversal when possible, do add indexes on foreign keys.

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Loading WhoIsActive Data on Azure SQL DB

Published 2023-04-26 by Kevin Feasel

Andrea Allred wants to know who’s doing what on this system:

I needed to collect sp_WhoIsActive into a table, but the twist was that it is on my Azure Managed Database, so I had to get creative with how I did it. We needed an Azure Pipeline to run it, but we wanted to record it every minute and firing a pipeline every minute adds up fast. So we decided that we would kick it off once an hour and have the process wait for a minute and then fire until the hour ended. Then it fire again at the top of the next hour and the same process would happen.

That’s an interesting way to do it. Another alternative might have been an Azure function app, which you could schedule to run every minute. I think that’d be a lot less expensive than running an Azure Pipeline, and this goes to show you that there are many ways to solve the same problem in Azure.

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Upgrading an Expired SQL Server Evaluation Edition

Published 2023-04-21 by Kevin Feasel

Chad Callihan loses track of time:

SQL Server Evaluation editions are great to use for testing early releases. When the real deal comes out, it’s best to upgrade then and there (probably Evaluation to Developer if you’re testing and experimenting). But what happens if you let an evaluation edition expire by accident? The good news is you can still upgrade but it’s a bit tedious.

Click through to see how.

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Transport Layer Security and SQL Server

Published 2023-04-21 by Kevin Feasel

Michael Howard provides an explanation:

Invariably, when I ask people what Transport Layer Security (TLS) does, they say something like, “it protects my credit card info when I buy things online.”

The response is not incorrect, but it’s not the whole story, either, and let’s just ignore the server-side credit card protection requirements and PCI compliance for a moment.

TLS provide three security services, with an optional fourth.

Click through for those services and some of the ways we can improve our security posture when connecting to (or hosting!) a SQL Server instance.

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Handling Error 574 during a SQL Server Upgrade

Published 2023-04-19 by Kevin Feasel

Tom Collins sorts out a nasty issue:

Script level upgrade for database ‘master’ failed because upgrade step ‘msdb110_upgrade.sql’ encountered error 574, state 0, severity 16. This is a serious error condition which might interfere with regular operation and the database will be taken offline. If the error happened during upgrade of the ‘master’ database, it will prevent the entire SQL Server instance from starting. Examine the previous errorlog entries for errors, take the appropriate corrective actions and re-start the database so that the script upgrade steps run to completion.

Read on to learn what caused this error and how Tom was able to work around it.

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Purging WSUS Synchronization Events

Published 2023-04-17 by Kevin Feasel

Hannah Vernon has a script:

Since Windows Server Update Services synchronizes the list of Windows Updates from the source Microsoft Servers on a regular basis, the history of sync events can become quite tedious to load in the User Interface. Frustratingly, there is no way through the user interface to remove old history for synchronization events. The SQL Server T-SQL code below creates a stored procedure that can be used to cleanup old events prior to a particular cut-off date. I run the code via a SQL Server Agent job daily, with a cut-off date of 30 days ago.

Click through for the stored procedure.

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Learning Important Postgres Settings for SQL Server DBAs

Published 2023-04-17 by Kevin Feasel

Ryan Booz helps a SQL Server DBA out:

Five years ago, I began my transition back to using PostgreSQL full-time, and it wasn’t the smoothest journey. One of the biggest reasons I struggled to make progress learning PostgreSQL early on was simply not knowing what I should be looking for. In fact, I often have conversations multiple times a month about the differences between SQL Server and PostgreSQL with folks setting out on a similar journey.

My guess is that you’re trying to figure out the same things, which is how you ended up on this series of posts.

Read on to take advantage of Ryan’s pain and suffering.

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