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Category: Bugs

VARCHAR Columns and Bytecode Version Mismatch in R

Dave Mason runs through a tricky problem with SQL Server Machine Learning Services:

During my testing, I’ve found R handles CHAR and VARCHAR data within the input data set as long as the ASCII codes comprising the data is in the range from 0 to 127. This much is not surprising–those are the character codes for the ASCII table. Starting with character code 128, R begins having some trouble. 

Read on to see the problem. Dave’s advice at the end is sound (and frankly, my advice for any string data in SQL Server).

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Issue with PolyBase and Cosmos DB

I found an issue with connecting to Cosmos DB from PolyBase after installing SQL Server 2019 CU2:

After upgrading to SQL Server 2019 CU2, I noticed some issues when trying to connect to a Cosmos DB collection via PolyBase. Specifically, I started getting the following error message:

Msg 105082, Level 16, State 1, Line 35
105082;Generic ODBC error: [Microsoft][MongoDBODBC] (110) Error from MongoDB Client: Server at <<my Cosmos account name>>.documents.azure.com:10255 reports wire version 2, but this version of libmongoc requires at least 3 (MongoDB 3.0) (Error Code: 15) Additional error <2>: ErrorMsg: [Microsoft][MongoDBODBC] (110) Error from MongoDB Client: Server at <<my Cosmos account name>> .documents.azure.com:10255 reports wire version 2, but this version of libmongoc requires at least 3 (MongoDB 3.0) (Error Code: 15), SqlState: HY000, NativeError: 110 .

Read on for a couple attempts at a solution and some more detail.

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PolyBase Bug Around Windows Authentication

I have a post documenting a bug in SQL Server 2019:

Here’s the short version of the bug. If you are connected using a Windows authenticated account and attempt to perform a PolyBase-related action, such as creating an external data source or querying from an external table, you receive the following error:

Msg 46721, Level 20, State 1, Line 5
Login failed. The login is from an untrusted domain and cannot be used with Integrated authentication.

Because this is an error with a severity level of 20, it kills your session.

Click through for the workaround. I had hoped that this would have been fixed with CU3, but it’s still in there.

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Query Store and Spinlocks

David Fowler takes a look at an issue with Query Store:

We moseyed on down to the server in question to take a look at it.  One thing stood out immediately, CPU was pegged out at 100% but SQL itself didn’t actually seem to be doing anything, transactionssecond was on the floor. Unfortunately this happened a while back and I didn’t think to capture any graphs or metrics at the time so you’re just going to have to take my word for this.

After looking into a few different things, the mention of spinlock contention came up.  I’ll be honest here, actual spinlock contention is rare and is something that I’ve seen cause an issue only a handful of times so it’s something that I don’t generally get to until I’ve ruled out just about everything else.

David’s scenario was on an older patch of SQL Server and it was fixed later. It’s a good reminder to keep those servers patched.

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Guids in Persisted Calculated Columns

Slava Murygin shows us some odd things which occur when you try to make a persisted calculated column out from a UNIQUEIDENFITIER data type:

This post is for you in case you decide to use Uniqueidentifier column in your table and then you think about including it into a Persisted calculated column.
You also might see it useful if you like weird or funny SQL Server behavior.

Slava has an Azure feedback item and it looks like someone tested the behavior in SQL Server 2019 and it works as you’d expect, so this must have been fixed sometime between then and now.

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Updating the Powershell Kernel in Azure Data Studio Notebooks

Bob Pusateri has a two-parter on Powershell notebooks. First up is the problem:

PowerShell Notebooks are a great new feature in Azure Data Studio, first becoming available in the November 2019 release. Like SQL notebooks, PowerShell notebooks are based on Jupyter Notebooks format, which are interactive documents containing text and executable code blocks.

Having some working PowerShell code that I wanted to share along with explanations and examples, I created a PowerShell Notebook. The only problem was my functions would never initialize. Actually they would never stop initializing – I would run the cell they were defined in, and it would just keep running forever.

And then Bob has the solution:

It turns out I did not have the latest version of the PowerShell Kernel running on my machine. The latest version is currently 0.1.3, and I had 0.1.2. Upgrading appears to have solved this issue for me – yay!

This solution also raises the issue that there is no notification from Azure Data Studio that a PowerShell Kernel exists or is in need of updating. I (and probably others) will just believe that as long as Azure Data Studio is up to date, we’re good to go. So how does one update their PowerShell kernel? Well, it’s simple, but not intuitive.

Read on to see how.

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Fixing Screen Repainting Issues in SSMS

Greg Low has a workaround for an annoying problem:

Once again, I’m seeing lots of customers reporting screen repainting issues in SQL Server Management Studio (SSMS). It mostly seems to affect version 18 but I’ve also seen it in version 17. And it’s most prevalent on Windows 10.

The typical issue is that you click on another open tab, and the contents of the tab doesn’t repaint. You are still seeing the previous tab. If you click into the tab, you start to see bits from both tabs.

Click through to see the fix. I’ve seen this issue pop up though I don’t remember seeing it on the latest version of SSMS 18…though now that I say that, I’m guaranteed to have the problem hit me today.

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Bug with UnmatchedIndexes and Filtered Indexes

Taiob Ali points out a bug in SQL Server Management Studio:

SQL Server Management Studio (SSMS) showplan root node properties have two attributes to indicate when a filtered index can not be used during a parameterized query. One is ‘UnmatchedIndexes’, and the other one is under ‘Warnings’ attribute. Due to a bug in SSMS, the attributes are also showing positive results with filtered index and non-parameterized queries.

Let’s look at an example. I am using the AdventureWorks database, which you download from here.

If you want this fixed, vote up this Feedback item.

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Static Analysis of Hadoop Libraries

Maxim Stefanov ran a static analysis of several Hadoop libraries and here are the findings:

After the analysis was completed, I chose the most interesting warnings and noticed that I had the same number of warnings in production code and in tests. Normally, I don’t consider analyzer warnings from tests. But when I divided them, I couldn’t leave ‘tests’ warnings unattended. “Why not take a look at them,” I thought, “because bugs in tests might also have adverse consequences.” They can lead to incorrect or partial testing, or even to mishmash. 

After I selected the most intriguing warnings, I divided them by the following groups: production, test and the four main Hadoop modules. And now I’m glad to offer the review of analyzer warnings.  

Read on for the list. Hopefully Maxim submitted a few pull requests or at least Jira tickets for the projects.

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Recovering From Parsing NaN Values

Slava Murygin shows how you can recover from a nasty TRY_PARSE error:

In my previous post I outlined very dangerous SQL Server problem, caused by usually not very harmful commands “PARSE” and “TRY_PARSE“: Having “NaN” value for REAL and FLOAT producing severe error.

This post will be about a major issue it causes and on how to fight it.

Will start from generating the problem.

Attention: Do not run that in production!!!

Slava’s serious about not running the code in a real environment.

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