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Category: Error Handling

Automatic Refresh in Power BI

Published 2023-05-15 by Kevin Feasel

Chris Webb does some ‘splainin’:

One of the most confusing things about troubleshooting Power BI refresh problems is the way Power BI will sometimes try running a refresh again after it has failed. It means that refreshes seem to take a lot longer than you would expect and also that more queries are run against your data source than you would expect. I don’t have all the answers but I thought it would be useful to highlight a few scenarios where it does happen.

Read on for two scenarios in which you might find this.

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False Alarms in Highly Available Postgres Clusters

Published 2023-05-12 by Kevin Feasel

Umair Shahid pulls the alarm:

False alarms can be a significant problem in highly available clusters of PostgreSQL. They can cause unnecessary downtime and disruptions that can impact the performance of the nodes. In this blog post, we will explore the causes, prevention, and resolution of false alarms in PostgreSQL clusters.

It’s a good idea to sit back and think about how complex the problem of high availability is, even if the service (SQL Server, Postgres, or whatever) offers capabilities to simplify a lot of it. The trick is that you want your service to fail over if and only if it needs to, but what tells you if it “needs to” is noisy signal.

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Fixing ORA-26086 in Azure Data Factory Pipelines

Published 2023-05-11 by Kevin Feasel

Emanuele Meazzo fixes a problem:

Turns out, ADF is rightfully trying to insert the rows in bulk, but Oracle doesn’t like it when the sink table has triggers, falling back to row by row insertion seems it’s too much to ask, so you end up with the error.
Searching on the good ‘ol wide web you’ll encounter this solution, that basically tells you to disable bulkload for the whole Oracle connection by setting EnableBulkLoad=0 in the connection string.
That wouldn’t work for me, because I’m bulk loading just fine everywhere else, so either I had to suffer slower performance on all the other inserts by disabling the bulk insert, or I had to create an additional and separate Linked Service to Oracle with the bulk insert disabled: doable but adding maintenance overhead when things change (two secrets to manage instead of one).

My solution? Super dumb.

Read on for a copy of the error message and Emanuele’s solution. There are two philosophies with regard to dumb solutions:

  • If a solution is dumb and it works, it isn’t dumb.
  • If a solution is dumb and it works, it’s still a dumb solution and you just got lucky this time.

I’m not quite sure under which category this falls.

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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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Blamestorming with PostgreSQL Errors

Published 2023-04-07 by Kevin Feasel

Robert Haas points the finger:

If an error message shows up in the PostgreSQL log, what program is malfunctioning? It’s easy to conclude that the answer is PostgreSQL, but that’s too simplistic.

For example, suppose these messages show up in my log file:

ERROR:  new row for relation “orders” violates check constraint “orders_d_check”
DETAIL:  Failing row contains (1975-03-16, 42).
STATEMENT:  insert into orders values (‘1975-03-16’, 42);

Error logs are always a “reading is fundamental” scenario and an exercise in applied logic. Sometimes the exercise is harder than others, such as the notorious “String or binary data would be truncated” in SQL Server or “Object reference not set to an instance of an object” in .NET. But in many cases, there’s enough information at least to get an idea of culprit and cause.

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Troubleshooting Azure Synapse Link for SQL Server Issues

Published 2023-04-06 by Kevin Feasel

Kevin Chant diagnoses an issue:

In this post I want to cover common Azure Synapse Link for SQL storage permission issues. Since I helped a fellow MVP out with this recently.

To be more precise, I want to show how you can fix one of the most common issues I tend to encounter with Azure Synapse Link for SQL. Which is access to the Data Lake Storage Gen2 account.

I have encountered issues like this a few times now. For example, when I was performing my file tests for Azure Synapse Link for SQL Server 2022.

Click through to learn more about a couple of common issues, their causes, and resolutions.

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SQL Alerts on Potential Attacks

Published 2023-03-31 by Kevin Feasel

David Fowler keeps his head on a swivel:

But let’s be honest, the above attacks are just going to be opportunistic hackers probably using an automated tool to hunt out open servers and try to exploit them, a bit like the guy walking down the road and trying all the car doors in the hope that someone will have left their unlocked. It someone’s specifically targeting your servers, the chances are that they’ll be a bit more sophisticated.

This is where things get a little more troublesome and where SQL doesn’t really give us any tools to help.

But there are warning signs that we can look out for and these can be certain error messages in the logs. There are three in particular that I see as red flags that something amiss may be going on.

Click through for those three warning signs and how you an create SQL Server alerts upon logging these messages. The errors aren’t guaranteed to be an attacker, though in reading them, I’d expect a high signal to noise ratio on them.

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Tips for Debugging DAX Code

Published 2023-03-14 by Kevin Feasel

Ed Hansberry has no bugs, but just in case:

When trying to get your DAX measures to work correctly, there are a number of tools you can use to debug, which I will briefly mention, but not go into depth on. Instead, this post is about how to think about debugging your code. I am focusing on DAX here, but many of the methods would apply to any type of code.

Read on for a series of tips around built-in capabilities, process, and the power of conversation.

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The Importance of Trace Flag 460

Published 2023-03-10 by Kevin Feasel

Jonathan Kehayias helps me understand that Trace Flag 460 is one of the best trace flags ever:

For most people that are reading this post, I’d venture to guess that you have no idea what Trace Flag 460 is or when you would use it. Well first off, let me tell you it’s a fully documented and supported trace flag, and it’s totally safe. In fact, on SQL Server 2019 and higher it is the default behavior when you create a new database. What does it do? It makes troubleshooting string or binary truncation issues easier by changing the error message that is returned from message ID 8152 and replaces it instead with message ID 2628. The trace flag is also available in SQL Server 2016 SP2 CU6+ and SQL Server 2017 CU12.

Read on to learn more about it and to remove a potential bit of confusion in the documentation.

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