Hey @Ajay Pandey​ ,

That message is related to delta caching, basically if a cluster is constantly scaling up or down then occasionally you might lose delta cache pieces. Determining the location of DBIO file fragments is the operation determining which executors the files were cached.

This is something that can be helped by trying a newer DBR such as 11.3 or 12.X. You could also try turning off the cache by setting the below configuration in the notebook and observing the behaviour:

spark.conf.set("spark.databricks.io.cache.enabled", "false")

You could also try optimizing the table(s)

%sql Optimize [table name]