Numerous disconnects from Semantic Model

[danielpitz]

I've asked this before, but missed the response asking for a log file.

My queries get disconnected frequently. It's getting to the point that it happens every 2 - 5 query runs.

I would upload a log file but I'm not sure if that's allowed here

[v-dineshya]

Hi @danielpitz ,

Thanks for reaching out to the Microsoft fabric community forum. 

Common Causes of Frequent Disconnects in DAX Studio:

1.Idle Timeout / Resource Constraints: If your machine or the Power BI Desktop file goes idle, or if memory usage spikes, connections may drop unexpectedly.

2. Power BI Desktop as the Host: If you're connected to a local PBIX file, DAX Studio connects to the Analysis Services engine hosted by Power BI Desktop. If that engine crashes, closes, or is reloaded (e.g., due to changes in the model), the connection is lost.

3. Auto-closing of Connection: Some versions of DAX Studio may automatically close a connection if too many queries are queued or an exception is thrown by the engine.

4. Model Recalculations or Refreshes: If the model is recalculating (due to dependencies or a background refresh), that may lead to a dropped session.

5. Bugs in Power BI or DAX Studio Versions: Sometimes recent updates introduce instability in either Power BI Desktop or DAX Studio.

Check the below things to fix it:

1. Update All Tools: Ensure you’re on the latest version of DAX Studio and Power BI Desktop. Compatibility issues can be a source of disconnects.

2. Check Diagnostics Logs in DAX Studio: You can generate and send logs: Go to Advanced > Start Tracing and Run a few queries until the disconnect occurs. Save the log and inspect the error

Note: If you'd like, I can help interpret a log file if you upload it here.

3. Try External Tool Connection: Instead of launching DAX Studio directly, try using External Tools from Power BI Desktop. Open your PBIX file, then click DAX Studio from the External Tools tab this binds to the same Analysis Services instance, which may reduce session instability.

4. Minimize Heavy Queries or Parallel Execution: If you're running large queries back-to-back, space them out or test running them with query timing disabled.

Note: Confirm you're using the latest DAX Studio version. Try running it as an External Tool from Power BI Desktop. If the problem persists, upload the trace log file.

If you find this post helpful, please mark it as an "Accept as Solution" and consider giving a KUDOS. Feel free to reach out if you need further assistance.
Thanks and Regards

[danielpitz]

I did not see this option on the Advanced tab in Dax Studio:
2. Check Diagnostics Logs in DAX Studio: You can generate and send logs: Go to Advanced > Start Tracing and Run a few queries until the disconnect occurs. Save the log and inspect the error

[v-dineshya · Accepted solution]

Hi @danielpitz ,

If you are not seeing the "Start Tracing" option under the Advanced tab in DAX Studio, it's possible you are Using a version that has moved or renamed this option Or you are missing the Developer or Diagnostics features due to how it was installed.

Please follow below steps.

Step 1: Ensure You are Using the Latest Version. Download and install the latest version.

If you’re using a version older than 3.x, the interface may be missing newer features like improved logging or integrated tracing.

Step 2: Enable and Use Diagnostics Logging

Option A: Use Built-in Tracing (New Versions)

Open DAX Studio. Go to the Advanced tab. Look for "Start Tracing" or "Enable Tracing". we want diagnostic logs instead.

If the button isn’t there, try using the menu: File > Options > Advanced and check for a logging setting.

Option B: Manual Logging via Command Line

If tracing doesn't appear, you can still collect logs manually:

Go to File > Options. Enable “Debug Mode” or “Verbose Logging” under Advanced. After enabling, try rerunning your queries until the disconnection happens.

Then go to this folder:

%localappdata%\DaxStudio\Logs

Note: You will find the latest .txt or .log files there.

Step 3: Try This Stability Workaround

Sometimes DAX Studio disconnects due to how it attaches to the Analysis Services process. Try the External Tools method:

Open your .pbix file in Power BI Desktop. On the ribbon, go to External Tools. Click on DAX Studio from there. This launches DAX Studio attached directly to Power BI’s Analysis Services instance. This method reduces the risk of connection drops due to mismatches or background refreshes.

If our response addressed, please mark it as "Accept as solution" and consider giving a "KUDOS". Feel free to reach out if you need further assistance.

Regards,

Dinesh

[v-dineshya]

Hi @danielpitz ,

As we haven’t heard back from you, we wanted to kindly follow up to check if the solution provided for the issue worked? or Let us know if you need any further assistance?
If our response addressed, please mark it as Accept as solution and consider giving a KUDOS. Feel free to reach out if you need further assistance.

Regards,

Dinesh

[danielpitz]

Sorry for the delayed response.

I've set the logging to verbose, will be using the tool more later today, and will see what happens, thanks

[v-dineshya]

Hi @danielpitz ,

Have you tried the verbose option?

we wanted to kindly follow up to check if the solution provided for the issue worked? or Let us know if you need any further assistance?
If our response addressed, please mark it as "Accept as solution" and consider giving a "KUDOS". Feel free to reach out if you need further assistance.

Regards,

Dinesh

[danielpitz]

I have it on verbose now, and I'll look at it when/if this instance disconnects. 

[v-dineshya]

Hi @danielpitz ,

Have you tried the verbose option?

we wanted to kindly follow up to check if the solution provided for the issue worked? or Let us know if you need any further assistance?
If our response addressed, please mark it as "Accept as solution" and consider giving a "KUDOS". Feel free to reach out if you need further assistance.

Regards,

Dinesh

[danielpitz]

I have it on verbose now, but of course it's mostly behaving more properly. I do have one log file from when it had a hard crash, as i call them, where I need to either use Task Manager or a dialog that pops up after a while to kill the program. I can give you that along with the time of the crash if it might help

[v-dineshya]

Hi @danielpitz ,

Thank you for your confirmation. As you mention that, Verbose is working fine. Till now no crash or  query disconnection not happen?. Let us know if you need any further assistance? If every thing is fine can  i close this thread?

Thank you

[v-dineshya]

Hi @danielpitz ,

We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet.In case we do not receive a response, we shall proceed to close this thread. For any further discussions or queries, please initiate a new thread in the Microsoft Fabric Community Forum, where we will be glad to assist you.

Thank you.

[danielpitz]

Sorry for not replying sooner. I'll try those suggestions, in particular the one about starting a trace, and let you know how it goes. Thanks

[v-dineshya]

Hi @danielpitz ,

As we haven’t heard back from you, we wanted to kindly follow up to check if the solution provided for the issue worked? or Let us know if you need any further assistance?
If our response addressed, please mark it as Accept as solution and consider giving a KUDOS. Feel free to reach out if you need further assistance.

Regards,

Dinesh

[v-dineshya]

Hi @danielpitz ,

As we haven’t heard back from you, we wanted to kindly follow up to check if the solution provided for the issue worked? or Let us know if you need any further assistance?
If our response addressed, please mark it as Accept as solution and consider giving a KUDOS. Feel free to reach out if you need further assistance.

Regards,

Dinesh

[danielpitz]

I'll say yes, but I only run Dax queries using Dax Studio, so I'm not sure where else it would happen. I don't use SSMS or Dax Query View (in PBI Desktop)

[lbendlin]

DAX Studio has its own timeout settings that you can play with, but usually these errors indicate more severe underlying problems in your network connectivity and stability.

[danielpitz]

If they only occurred after periods of inactivity I'd assume that's what it was. It often occurs while i'm running queries one after the other, when I'm testing things. I'll run the query, make a change, then try to run it again and I see a message:
Can't obtain the account information for 'myname@myemailaddress.com' whle trying to refresh the token.
The log file seems to indicate it was a timeout, but again, it's while I was in the middle of running queries in succession, so it's not like I left it sitting there for a while. This is from the log file:
2025-04-30 10:08:49.433 -04:00 [WRN] ConnectionManager RetryPolicy A connection error occurred: The connection either timed out or was lost.
Attempting to reconnect (retry: 1)
Microsoft.AnalysisServices.AdomdClient.AdomdConnectionException: The connection either timed out or was lost. ---> Microsoft.AnalysisServices.AdomdClient.AdomdErrorResponseException: The '<eupi>966C232B-2357-4C83-8F4B-E848A556AA66</eupi>' session ID cannot be found. Either the session does not exist or it has already expired.

[andrewsommer]

Assuming import mode?

Are you using a data gateway?  Is the gateway updated?  Make sure the gateway server has stable network access and is not under high CPU/memory pressure.

Agree with lbendlin that disconnect issue sounds off and a timeout is more common (I’ve seen these a ton). 

• Optimize DAX queries (especially in visuals or calculated tables/columns).
• Consider breaking up large models or aggregating data more aggressively.
• In Premium/Fabric, review capacity metrics in the Capacity Metrics App (e.g., CPU/memory spikes).
• Increase timeout limits in the data source, if configurable (SQL Server, etc.).

Please mark this post as solution if it helps you. Appreciate Kudos.

[danielpitz]

We dont' use data gateways - we found them to be too slow (although that may have been an implementation issue, but that stuff's all magic to me, so what do I know). We use the Personal Cloud Connection option.

I've asked around and this doesn't happen to others on my team, but to be fair I probably use Dax Studio more than anybody else.
How do I adjust the timeout settings in Dax Studio?

[lbendlin]