Forum Discussion

moritzbartram's avatar
moritzbartram
Frequent Visitor
10 months ago
Solved

Mirrored Oracle Error

Hi everyone,  I'm having trouble to create a mirrored oracle item. I've followed the set-up guide and configured my oracle database accordingly, but get the following error:    The message a...
data engineering
  • moritzbartram's avatar
    moritzbartram
    10 months ago

    Hi v-kpoloju-msft,

     

    thanks again for your reply. I've already been in contact with the fabric support team and they confirmed that the error I'm getting results from the amount of tables ~10000 that are in my database and they cannot be displayed. So this is just a UI error that can be circumvented by creating mirror items via Rest-API. 

    Thanks again for your help! 

    Best regards

v-kpoloju-msft's avatar
v-kpoloju-msft
Community Support
10 months ago

Hi moritzbartram,

Thank you for reaching out to the Microsoft Fabric Community Forum. Also, thanks to tayloramy, for his inputs on this thread.

The message “A task was cancelled” usually means that Fabric was not able to finish connecting to your Oracle database while trying to fetch the list of available tables or schemas. In most cases, this happens due to a timeout or connectivity delay between the Oracle server and the on-premises data gateway, rather than an issue with credentials. Here are a few steps you can try to get this working below those are mentioned.

Check connectivity from your gateway machine: From the server where your On-premises Data Gateway is installed, try connecting to Oracle using the same connection string or run a tnsping command. This helps confirm that the gateway can reach your Oracle database without latency or firewall issues.

Ensure the gateway and Oracle setup meet Fabric’s requirements: Use the latest version of the On-premises Data Gateway (v3000.282.5 or later). Verify your Oracle version is supported and LogMiner is enabled for mirroring.
https://learn.microsoft.com/en-in/fabric/mirroring/oracle-tutorial 
https://learn.microsoft.com/en-us/fabric/mirroring/oracle-limitations 

Limit what Fabric needs to load: If your Oracle user has access to many schemas or tables, the connection step can time out. Try using a user with access to only the specific schema/tables you need to mirror.

Restart the gateway and retry: Sometimes restarting the gateway service helps clear any hung sessions or old cache.

Check for encryption or TLS issues: If your Oracle instance enforces specific encryption algorithms, make sure they align with what the gateway supports.

Hope this helps. Let us know if you have any doubts regarding this. We will be happy to help.

Thank you for using the Microsoft Fabric Community Forum.

 

  • moritzbartram's avatar
    moritzbartram
    Frequent Visitor
    10 months ago

    Hi v-kpoloju-msft,

     

    thanks for your reply! The gateway I'm using work fine for the connection when I try to access the data via a copy activity (within a pipeline), then I can see all my tables and preview my data. 
    After inspecting the gateway logs I can see that errors appeared when I tried to set up the mirrored database, but I don't get relevant information out of it. 
    The error is: 'Unable to open the Server service performance object. The first four bytes (DWORD) of the Data section contains the status code.'
    The gateway version is 3000.282.5. 

    I already tried restarting the gateway. Do you have any other idea? 
    Thank you!

    • spaceman127's avatar
      spaceman127
      Super User
      10 months ago

      Hi moritzbartram ,

       

      I ran some tests yesterday with Oracle Database version 19.3.

      I also had a lot of problems at the beginning.

       

      Maybe we can solve this.

      I have the following questions.

       

      1. Which Oracle version are you using?

      2. I assume the Data Gateway is up to date?

      3. Have you installed the Oracle Client and adjusted the tnsnames.ora accordingly?

      4. Does your user have the permissions? Have you tested this with SQL Developer or SQL Plus?

       

      If you have any questions, just let me know.

       

      Best regards

       

       

       

       

    • v-kpoloju-msft's avatar
      v-kpoloju-msft
      Community Support
      10 months ago

      Hi moritzbartram,
      Thank you for the in detailed follow-up question.

      Since your Oracle connection works fine in the copy activity, that confirms the gateway, and credentials are good, so the issue is likely with the local performance counters on the gateway machine. The log message

      “Unable to open the Server service performance object…”
      is a Windows-level error that usually appears when performance counters are corrupted or not accessible to the gateway service.

      You can try rebuilding them by opening Command Prompt as Administrator and running:

      lodctr /R

      Then restart the On-premises Data Gateway service and retry the mirror setup.

      If the problem persists, make sure the Server service (LanmanServer) is running and the gateway service account has permission to read performance counters. This usually clears the “task was canceled” error when creating the mirrored Oracle item.

      Hope this helps. Let us know if you have any doubts regarding this. We will be happy to help.

      Thank you for using the Microsoft Fabric Community Forum.

      • moritzbartram's avatar
        moritzbartram
        Frequent Visitor
        10 months ago

        Hi v-kpoloju-msft,


        I ran the command, succesfully rebuilt the performance counters and restartet the gateway. Unfortunately the error persists. I updated the gateway, but it also did not work.

        Any other ideas? 
        Thank you!