A Fine Slice Of SQL Server
Deborah Melkin reviews the logs:
I don’t remember the search criteria, but I did stumble upon this page, Azure Data Studio Troubleshooting
As I read through this, I hit the section about Debug log location. I remember that I had a problem installing something on Azure Data Studio last summer and someone at Microsoft had helped me by pointing me to the log files.
Read on for the full story.
Comments closedIn the past I’ve written about monitoring identity columns to ensure there’s room to grow.
But there’s a related danger that’s a little more subtle. Say you have a table whose identity column is an 8-byte bigint. An application that converts those values to a 4-byte integer will not always fail! Those applications will only fail if the value is larger than 2,147,483,647.
This post specifically pertains to identity columns but don’t forget those non-identity columns when testing.
Comments closedJeffrey Wang shares a few tips to avoid issues with window functions in DAX:
Several people had reported running into errors when trying the window functions on fact tables. Let’s look at an example by first adding a calculated table of three columns to the model that is defined by the following DAX expression, and then, add all three columns to a table visual as shown in Figure 1.
Read on for more. This is an area where expected behavior does differ from what you get with window functions in T-SQL.
Comments closedBill Fellows finds out whose line (feed) it was, anyway:
I ran into an issue today that I wanted to write about so that maybe I remember the solution. We ran into a case where the source data in a column had an unprintable character. In this case, it was a line feed character, which is ASCII value 10, and they had 7 instances in this one row. “How did that get in there? Surely that’s an edge case and we can just ignore it,” and dear reader, I’ve been around long enough to know that this is likely a systemic situation.
Click through for two ways of answering this against data already in SQL Server, as well as one additional route explained but sans demonstration.
Comments closedMarco Russo and Alberto Ferrari catalog some errors:
The expression contains columns from multiple tables, but only columns from a single table can be used in a True/False expression that is used as a table filter expression.
This error is seen when the predicate includes column references from more than one table. For example, if we need a measure that returns the sales made to customers living in the same country as the store, we could try to write the following measure:
Read on for several examples and solid guidance on how to resolve these common issues.
Comments closedKamil Nowinski goes down a rabbit hole:
This happens on the customer’s Synapse workspace where we have a public network disabled, so only private endpoint and managed VNET are available. Additionally, you probably spotted, that it took over 3 minutes to actually get this message. Hence, as a next step, in order to minimize the potential causes I simplified the query to make sure I have access to the Storage, by listing the files:
Click through for a story of pain, followed by glorious resolution.
Comments closedBut interestingly enough – we would be getting an added benefit here. Even if there is no SQL injection attack, it’s still possible that such errors would be raised by the application – simply due to bugs.
Furthermore, these errors in the database may be happening without anyone even noticing! How could that be, you ask? Well, it could be due to bad error handling that “swallows” the error entirely, or because the errors are logged but no one is bothering to look at the logs, or maybe because the errors are caught but an undetailed error message is logged/displayed to the user (I can’t even count how many times I encountered “general database error” messages in applications), or because the developers simply decided to mark this as a “known issue” that they didn’t bother to fix and they didn’t think to ask their DBA about it… The reasons are numerous and varying.
Click through for the scripts. I had built something similar about a decade ago, a simple WPF app which watched for errors. I messaged him with something like “You missed a comma in that IN clause” and I saw him pop up from his cubicle and look around, trying to figure out how I could peek over his shoulder and see the query.
1 CommentChris Webb follows up on a prior post:
One of the most popular topics I’ve ever written about here is the dataset refresh errors you get with dynamic data sources and the Web.Contents function in Power BI (see here and here for example). Recently I learned about an interesting new detail regarding this problem that I thought was worth blogging about, and which may help someone trying to troubleshoot it.
Read on for the scenario, as well as what you can do to avoid an issue.
Comments closedI am often asked about all kinds of various errors, of course with absolutely no context. I also get asked what error X is or means or says… I don’t remember that stuff off the top of my head. The thing is, you kind of need SQL Server to go look it up and there have been a plethora of times when this wasn’t possible. I’ve also noticed that people tend to give you just the error number and not anything else.
Read on to learn more about what Sean has created, akin to the SQLskills wait stats compendium.
Comments closedThomas Williams illuminates us on the caching process:
Caching in R Markdown is a valuable step to get your app, report or visualisation more production-ready. There are one or two potential issues to watch out for, especially when deploying a cache-enabled R Markdown file to a Shiny server – in this post I’ll go over some of these “gotchas”, and how you could address each one.
Click through for those three gotchas.
Comments closed