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Category: Bugs

The Pain of fn_xe_file_target_read_file

Published 2024-10-21 by Kevin Feasel

Tom Zika plants a flag:

I haven’t had a rant post in a while. There is a saying: “Anything before the word ‘but’ is ignored”. I love Extended Events, but … reading the extended event file is so much pain.

It feels like there is a conspiracy between Microsoft and Big Pharma SQL Monitoring because the best analytics tool available in SQL Server (and I mean Extended Events and Query Store of course) have the worst GUI and supporting tools. I’m focusing on XE in this post.

Read on for Tom’s rant. To add on to it, the feedback item Tom links to now has a new update from Dimitri Furman, indicating (based on how I’m reading it) that the fix will be in SQL vNext, not SQL Server 2022.

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The State of the ANY Aggregate Transformation

Published 2024-09-16 by Kevin Feasel

Paul White covers an aggregate operator:

SQL Server provides a way to select any one row from a group of rows, provided you write the statement using a specific syntax. This method returns any one row from each group, not the minimum, maximum or anything else. In principle, the one row chosen from each group is unpredictable.

The general idea of the required syntax is to logically number rows starting with 1 in each group in no particular order, then return only the rows numbered 1. The outer statement must not select the numbering column for this query optimizer transformation (SelSeqPrjToAnyAgg) to work.

Read on for information about this internal operator, a bug that existed in it for a long time, and the current state of fixes.

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The Brokenness of TABLESAMPLE

Published 2024-09-10 by Kevin Feasel

Paul White walks us through some issues:

Initial testing went well, which was a pleasant surprise. Soon enough though, errors started to appear in the tool’s output. That’s not entirely unexpected since ensuring consistent results under high concurrency tends to expose all sorts of niggly edge cases. It’s still an annoyance because debugging edge cases in trigger code can be tricky and laborious.

What was a surprise though was the nature of the error messages.

Read on for the full story. Paul has also created a feedback issue covering a problem with the function.

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“General Failure” and Query Store Compilation Times

Published 2024-08-14 by Kevin Feasel

Kendra Little warns us not to let a person named General Failure run your military:

This post demonstrates two related bugs with plan forcing in Query Store which increase the likelihood of slower query execution and application timeouts in SQL Server environments.

These bugs are most likely to impact you if:

  • You use the Automatic Plan Correction feature in SQL Server, which automatically forces query plans.
  • Anyone manually forces query plans with Query Store.
  • You have slow storage, which can increase your likelihood of having longer compilation times.

The General Purpose tier of Azure SQL Managed Instance and Azure SQL Database feature both slow storage and Automatic Plan Correction enabled by default. So, weirdly enough, your risks of suffering from this problem are high if you are an Azure SQL customer.

In the words of the great John Madden, that’s a heckuva bug.

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Losing .NET Code with SSIS 2016 Package Deployment

Published 2024-08-02 by Kevin Feasel

Andy Leonard goes on a quest:

…when one of our earliest SSIS framework customers reached out to share – in the very nicest way possible – that Fail Application on Package Failure in our SSIS framework was “not working.” My response was, “Great Scott!”

The customer is running SQL Server 2016. That’s fine for EDNA’s SSIS frameworks because we have framework versions that work with several versions of SSIS and SQL Server from 2012 forward. I maintain a collection of virtual servers built using the tools available for each version, including the operating systems and versions of Visual Studio, SSIS, and SQL Server.

Read on for the context, the story, and what Andy was able to do about it.

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Date Calculation Bug in Power Query ODBC Code

Published 2024-04-03 by Kevin Feasel

Meagan Longoria files a report:

I was working on an imported Power BI semantic model, adding some fiscal year calculations to my date table. The date table was sourced from a view in Databricks Unity Catalog. I didn’t have access to add more fields to the view, so I was adding the fields in Power Query first, with plans to request they be added to the view in the future. I got some unexpected results, which turned into a bug being logged for the ODBC code for Power Query.

If you are only analyzing data in the last 20 years, you won’t see this bug. But if you are doing long-term analysis including years before 2000, you might just run into it.

Read on to see the bug, how you can replicate it, and three workarounds you can use to avoid it.

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GUID Conversion and the Serverless SQL Pool

Published 2024-02-22 by Kevin Feasel

Reitse Eskens hits a weird error:

One of the transformations is to change one primary key column from integer to GUID. This is something you can do with some trickery you’ll see in the code. But what I found was that, even though the primary key is unique, the GUID’s weren’t. And then the fun starts digging into the why…

Read on for the research Reitse performed. I don’t even have a good guess for this, it’s so weird. It feels like a bug but it’s weird regardless.

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Cannot Create Property ‘groupid’ On String

Published 2024-02-16 by Kevin Feasel

Barney Lawrence fixes a problem in Azure Data Studio:


This is a solution to a bug I’ve encountered in Azure Data Studio when trying to create new connections. that leads to an error message of cannot create property ‘groupid’ on string ‘.

File this post under “things I couldn’t find a neat answer to in Google so I figure I’d best create a page for it”.

Read on for Barney’s answer as I lament how far downhill Google has gone as a search engine.

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When Online Index Rebuilds Aren’t

Published 2024-02-08 by Kevin Feasel

Kendra Little finds a bug:

I found a nasty bug in SQL Server and Azure SQL Managed Instance recently: sometimes an “online” index rebuild of a disk-based rowstore clustered index (basically a normal, everyday table) isn’t actually “online”. In fact, it’s very OFFLINE, and it blocks both read and write queries against the table for long periods.

If you manage to make it through a rebuild successfully, the problem goes away for future rebuilds of that clustered index – likely leaving you bruised and bewildered.

Click through for the details, including repo scripts and explanation of what should happen in this case.

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Working around a Contained Availability Group Error

Published 2023-12-05 by Kevin Feasel

Sean Gallardy talks about an error:

Contained Availability Groups are the most recent update to the Availability Groups feature, and a great update at that! They are completely new in SQL Server 2022, and like any new feature (or even mature ones) there will be some bugs. Enter in some Access Violations (AVs) that may occur when creating a new contained availability group.

Read on for an example of the error and what you can do until Microsoft fixes it.

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