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Category: Error Handling

Error Handling in T-SQL Stored Procedures

Published 2023-12-12 by Kevin Feasel

Erik Darling intimates that some of our code might occasionally have errors or might experience circumstances in which not everything is in perfect alignment:

Okay, look, the best post about this is, of course, by Erland Sommarskog: Error and Transaction Handling in SQL Server

Just like Erland, it has three parts and three appendices. If you want to learn how to do a whole lot of things right, give yourself a couple days to read through and digest all that.

What I’m here to talk about is some of the stuff you should think about before implementing any error handling at all.

I agree with most of Erik’s opinion here. My very mild disagreement is that I’ll still protect against things like invalid parameters or logic errors (start date before end date) in the stored procedure. I do that for three reasons:

  • Defense in depth isn’t just a security principle–it’s also a code practices principle.
  • The app gets things wrong, too. Sometimes, the app dev accidentally sends parameters in the wrong order, and it’s better to get an error early on in development versus thinking everything works because the procedure called successfully and ship it.
  • Even if “the” app correctly handles inputs, there’s always a chance some other app or process will call this stored procedure and it might not have the same error handling code built in.
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Failure Writing Backups to Azure Blob Storage Due to Limits Reached

Published 2023-11-29 by Kevin Feasel

David Fowler hits a wall:

Picture this, you’re happily backing up your database to a Azure blob storage until suddenly it starts mysteriously failing with the error…

Write to backup block blob device https://****** failed. Device has reached its limit of allowed blocks.

What’s going on, nothing’s changed?!

Read on to learn the cause of this issue as well as three ways to fix it.

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When an Update Doesn’t Update

Published 2023-11-29 by Kevin Feasel

Aaron Bertrand offers some troubleshooting advice:

Tell me if you’ve heard this one before:

I changed data from my application, but when I checked the database, I couldn’t see the change!

I’ve seen this. Loads. It can be quite perplexing for folks because they expect to see an error message if the insert, update, or delete failed. I put this post together to provide some things you can investigate if this happens to you – you are sure that you updated the data, but when you check using SQL Server Management Studio (SSMS), your change isn’t there. For the remainder of the post, I’m going to use the word “update” to mean any change to the data, even MERGE {shudder}.

Read on for three major classes of reason. One bonus reason: you left the transaction open. Most application frameworks will close transactions after a statement, but if you’re hand-writing transaction logic in your app, forgetting a COMMIT can happen.

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Failed to Update Replica Status Due to Exception 35222

Published 2023-11-24 by Kevin Feasel

Sean Gallardy troubleshoots a problem:

Read Scale Availability Groups can be pretty useful in the right places and for the right things and were a latest feature update for AGs until Contained AGs came along in 2022. Read Scale AGs don’t integrate with clustering of any type and they behave somewhat as mirroring used to where there is no real coordination of resources and it is up to the administrators to make the proper judgement calls or automate whatever possible scenarios they deem important.

Read on to see what this error means and why it’s less of a problem than it first appears.

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Azure Database for MySQL Flex Server and Power BI

Published 2023-11-22 by Kevin Feasel

Denny Cherry dips a toe into unfamiliar waters:

Recently, I upgraded our core Azure SQL Database for MySQL Single Server to Azure SQL Database for MySQL Flex Server. The migration was pretty straight forward and I simply did an export with mysqldump and then an import with MySQL. The problem came up when I tried to use Power BI (PBI) and connect to to the Azure SQL Database for MySQL Flex Server instead. When I tried to connect PBI to the Flex server I kept getting “The given key was not present in the dictionary”.

Read on to see what Denny did to resolve the issue.

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Displaying End-User-Defined Characters (EUDC) in SSMS

Published 2023-11-21 by Kevin Feasel

James Ferebee notes a problem:

A customer opened an interesting case stating SQL Server Management Studio (SSMS) would not display EUDC (End-User-Defined Characters) properly. More information on EUDC can be found here: End-User-Defined and Private Use Area Characters. 

After testing, it was identified by default, both SQL Server Management Studio and Visual Studio encountered this problem. In contrast, Notepad.exe displayed the desired character as intended. A shared aspect of SSMS and VS is the use of Windows Presentation Foundation (WPF).

Read on to see an example of how to create an EUDC and the workaround. I’d never even heard of EUDCs before, and the steps involved to get it to work probably explains why.

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Network Troubleshooting for Azure Synapse Analytics

Published 2023-11-17 by Kevin Feasel

Sergio Fonseca continues a series on Azure Synapse Analytics connectivity problems:

In this post I will speak about how to capture a network trace and how to do some basic troubleshooting using Wireshark to investigate connection and disconnection issues, not limited to samples error messages below:

  • An existing connection was forcibly closed by the remote host, The specified network name is no longer available, The semaphore timeout period has expired.
  • Connection Timeout Expired. The timeout period elapsed while attempting to consume the pre-login handshake acknowledgement. This could be because the pre-login handshake failed or the server was unable to respond back in time. The duration spent while attempting to connect to this server was – [Pre-Login] initialization=5895; handshake=29;
  • A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 0 – The semaphore timeout period has expired.)
  • A connection was successfully established with the server, but then an error occurred during the login process
  • Failed to copy to SQL Data Warehouse from blob storage. A connection was successfully established with the server, but then an error occurred during the login process. (provider: SSL Provider, error: 0 – An existing connection was forcibly closed by the remote host.) An existing connection was forcibly closed by the remote host
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Tabular Model Calculation Groups and Compatibility Level

Published 2023-11-16 by Kevin Feasel

Olivier Van Steenlandt sorts out a problem:

While I was writing another data recipe, I ran into an issue. For some reason, the “Create Calculation Group” was not visible / enabled in Tabular Editor.

I tried to create a Calculation Group by right-clicking on the Table Folder –> Create but the option wasn’t available.

I tried an alternative way: going to the Model Section in the Tabular Editor toolbar. But unfortunately, the option to create a new Calculation Group was disabled.

Read on to see how Olivier solved this problem.

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Pulling XMLA-Modified Power BI Datasets into Source Control

Published 2023-11-01 by Kevin Feasel

Marc Lelijveld has a fix:

Have you ever found yourself stuck with a modified Power BI dataset, thanks to those well-intentioned but troublesome changes you made through the XMLA endpoint? Does that sound familiar to you? What seemed like a convenient solution quickly turned into a frustrating challenge when you encountered the error message in the Power BI Service.

You wanted to seamlessly continue your development journey in Power BI Desktop, avoiding the need for a full data refresh or just quickly making that one small change, but now hitting a roadblock when trying to download PBIX file. The error message declared that your data model had been modified with the XMLA endpoint. But now, with Git integration you can overcome this challenge!

Read on to see how.

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