topic Re: Linked Table display rows of NULL data in Data Engineering

Linked Table display rows of NULL data

GregMarbais — Mon, 21 Apr 2025 19:04:07 GMT

Hey Everyone, I'm thinking this will need to be a support ticket but wanted to see if anyone else has seen this.

Basically, I have a whole medallion architecture set up which processes data. I link the processed tables to a Lakehouse which I then serve to users. So each user group has their lakehouse that links back to the processed table lakehouse which links back to data warehouses (generally no more than 2 links in the "chain").

Recently, tables that had been working just fine in the user group lakehouses have started being a problem randomly. Basically, one of the linked tables will show a table of nothing but null values. When viewed through the lakehouse, datawarehouse, via PowerBI desktop, dataflows - they all show the linked table is just a bunch of rows of null values in each column.

It happens randomly (or at least in no way that I can think of). I'm able to solve it by deleting the linked table and waiting a minute or two then recreating the linked table.

So far the easiest thing is to just fix it rather than preserve it and report it to Microsoft.

Has anyone else seen this? Anyone know of a permanent solution?

Re: Linked Table display rows of NULL data

Anonymous — Tue, 22 Apr 2025 06:51:25 GMT

Hi GregMarbais ,

Thank you for reaching out to the Microsoft Fabric Community.

What you're experiencing with linked tables intermittently displaying rows of NULLs is something we've seen in a few complex medallion-style deployments. It often points to a temporary metadata desync in the linkage particularly when lakehouses are chained or when refresh operations overlap.

As you mentioned recreating the linked table triggers a metadata refresh, which is why it resolves the issue temporarily.

Here are a few suggestions that may help:

Watch for schema changes in the source lakehouse tables even subtle changes can affect linkage integrity.
Consider scheduling refreshes with slight offsets across linked lakehouses to reduce potential timing conflicts.
Use the "Refresh schema" option on the linked table before deleting it, this can sometimes resolve the issue without full re-creation.
If possible, enable logs or monitoring to catch when and how the issue starts this may uncover patterns.

We understand the instinct to fix it quickly and move on, especially if it's faster than reporting. However, since this seems to be recurring and could affect others with similar architectures, we recommend raising a Microsoft support ticket. This will ensure the issue is officially tracked and can contribute to any long-term improvements or fixes.

If this post helps, then please give us Kudos and consider Accept it as a solution to help the other members find it more quickly.

Thankyou.

Re: Linked Table display rows of NULL data

GregMarbais — Tue, 22 Apr 2025 12:58:26 GMT

Anonymous , I'll look at the scheduled refreshes. Do you have a document that shows how to refresh the schema? I'm not seeing a way that I'm able to do that. I'll enter a support ticket as well.

Re: Linked Table display rows of NULL data

Anonymous — Thu, 24 Apr 2025 05:05:08 GMT

Hi [OP's name],

Currently, there isn’t a dedicated documentation page specifically for refreshing the schema on linked tables in Microsoft Fabric. However, you can find general information on schema management and optimization in the Schema Optimization Best Practices documentation, which may provide helpful context for your setup.

Unfortunately, the "Refresh Schema" option isn't extensively documented yet. I recommend continuing with the steps I shared earlier and opening a support ticket to ensure the issue is tracked properly.

If this post helps, then please give us Kudos and consider Accept it as a solution to help the other members find it more quickly.

Thankyou.

Re: Linked Table display rows of NULL data

Anonymous — Fri, 02 May 2025 02:09:21 GMT

Hi GregMarbais ,

Could you please confirm if the issue has been resolved after raising a support case? If a solution has been found, it would be greatly appreciated if you could share your insights with the community. This would be helpful for other members who may encounter similar issues.

Thank you for your understanding and assistance.

Re: Linked Table display rows of NULL data

GregMarbais — Mon, 05 May 2025 13:38:05 GMT

Anonymous I've subitted a support ticket