Querying a parquet file with fields of type INT64 generates an immediate error in the complex parquet reader with an error of "Unsupported nullable converted type INT_64 for primitive type INT64". Attempts to work around this via explicit CAST() and CONVERT_FROM() are unsuccessful. The suggestion from drill-users is that an implementation needs to be made at https://github.com/apache/drill/blob/9993fa3547b029db5fe33a2210fa6f07e8ac1990/exec/java-exec/src/main/java/org/apache/drill/exec/store/parquet/columnreaders/ColumnReaderFactory.java#L303.
If related, a similar INT32 type field in the same file exhibits this problem, but can be worked around via an explicit CAST() to INT.
At this time, I do not have a sanitized parquet file to submit as a reference example.
Reference thread on drill-users list: http://mail-archives.apache.org/mod_mbox/drill-user/202001.mbox/%3cCAJgUOA53LDKxqsH1fSVtJ+dk5421Eg4Aw4PaiM++8BfErxDvjQ@mail.gmail.com%3e