Hi Team,
I am getting following error while querying JSON file

"(java.lang.Exception) UNSUPPORTED_OPERATION ERROR: Schema changes not
supported in External Sort."

I have identified the root cause as one of the column has NULL value for
certain rows and STRING value for certain rows

I am trying to find out How drill decides the datatype of columns and
identify the schema changes.

 I tried following changes in data and got different results.

Case 1  - If I remove order by clause in the query then I don't the error.
Point to note, this specific column is not part of order by clause. But it
is part of select list

Case 2 - If I keep only two rows in file, one with NULL data and other with
STRING data for given column then no error. Query returns the data
successfully

Case 3 - I change the value of given column in first to from NULL to empty
string that is two double quotes then no error

Previously somewhere I has read that drill reads initial certain rows of
JSON and decides the datatype but not able to find the same now in the
documentation.

Thanks and Regards
Prabhakar

Reply via email to