Forum Discussion
Copy Data activity fails with KeyNotFoundException
That's helpful information; thank you. The Copy activity ran fine with no errors this week, so it does indeed seem likely that the issue is a transient one. I'll set the activity to 2 retries and see whether performance continues to be better for the next few eweks.
If partition columns contain nulls or unexpected values, the dictionary used for partition mapping may fail.
This could trigger a KeyNotFoundException during file path resolution.
I've just confirmed that the partition columns never contain null values. I'm not sure what an unexpected value would look like; can you say more about that possibility?
If it matters, whenever I see this error message, the specific path is not a new or unexpected one - it's a file in a directory to which previous runs of the pipeline wrote other files with no problem.