Hi @stefan_erste ,

I'll check with the exact same cluster setting tomorrow's morning. 

In the meantime - do you use some special characters in your tag's key or value?

Because if you have unusual tags like below - in this case I have dollar sign in my key and space in my tag value I get the same error:

To mitigate that you need to escape using backtick, like below:

tags = [
    "`my_tag$` = `my tag value`"    
]
for tag in tags:
    query_template = f"SET TAG ON COLUMN default.employees.Id {tag}"
    #print(query_template)
    spark.sql(query_template)

With backticks it works as expected and I can use non standard characters to define tag's key and value:

And as a prove that it worked, here an output from information_schema.column_tags: