Forum Discussion
Error ingesting json files in warehouse table
A final update for now at least: Microsoft has confirmed this is a bug, they hope to fix in the 1st quarter of 2026.
In the mean time they suggest to ingest it as a string and than use a notebook to parse the json array back into its original columns, or change the source, which for us wasn't an option.
Since it took ages for them to got to this stage I had already figured out I could use a notebook to read the json files in the lakehouse, read them into a dataframe, and when all files were read, write that dataframe to a table, in my case with an option "overwrite" since this is just a raw staging table.Final kicker: They want me to give permission to archive the case (no doubt because of their KPI's), but the bug is not registered on MS's known issue list. I want them to document it there, but they for some reason don't want to do that, they want to keep it internal, so now my Dutch stubberness is playing up .
The python code was quite simple in the end, even though we had multiple nested arrays. I used co-pilot to do the heavy lifting for me since i had to alias about 30 columns since i had to put the data in an existing table and the names needed to match
These are the libraries I needed:
Folder path to read json files
Exploding the main body of the json (just part of it, as example)
Thats it in a nutshell
I have tried the above solution, but it doesn't work.
I have a case open with MS, according to co-pilot the way Fabric handles json has become more strict since they launched the preview of the new activity copy job. But I can't find any real resource to confirm this. I will be pushing MS for an answer on that.
Right now I am trying the solution tayloramy suggested, which puts the json as a string in a column and than parsing it. That is going to be a bit of a learning curve for me though. I will keep this thread updated if I find a solution and how i have done it.
Hi smeetsh,
Thanks for getting back with an update. It sounds like you are already exploring a solid workaround with tayloramy, suggestion of storing the JSON as a string and then parsing it totally understandable that it might take a little learning curve.
Good call on keeping the case open with Microsoft as well, since their confirmation on the stricter JSON handling will be the most reliable path forward. Please do share back here once you hear more or have success with your approach, I’m sure it will help others running into the same issue.
Thank you.
Hi smeetsh,
Just checking in to see if the issue has been resolved on your end. If the earlier suggestions helped, that’s great to hear! And if you’re still facing challenges, feel free to share more details happy to assist further.Thank you.
Good afternoon v-kpoloju-msft It has not been resolved yet. I am still working through the notebook. The suppliers API is not helping me due to the complexity of nested json libraries within libraries 🤣 .. I do get a little bit further everyday though.
I did get feedback from Microsoft though, which make me feel that this may be a bug. The response last Monday was :"I’ve reproduced the issue on my end and confirmed that it appears to be related to the Lakehouse. We’ve already opened a collaboration ticket with the relevant team to investigate further.
We truly appreciate your patience and understanding while we work through this. Please allow us a little time, and we’ll keep you updated as soon as we have more information."
For now we are handling this as a two pronged approach
1: Trying to get the notebook to work, once I have a working notebook I will post sample code here
2: Waiting (and chasing MS) to see if this is a bug or caused by an update.
