For Avro tables the column information in the underlying database of the Hive metastore can be different from what is specified in the 'avro.schema.url' file. HIVE-6308 aimed to improve upon this, but for older tables the two don't necessarily align.
There are two possible cases:
- Hive's underlying database contains a column, which is not present in the Avro schema file. In this case we encounter a NullPointerException in DescribeResultFactory.java#L189 when trying to lookup the column in our internal table.
- The avro schema contains a column, which is not present in the underlying database. In this case the column will not be displayed in describe formatted.