Query plan signature vs Information schema


For a sql that is of scan type (say select * as a case), the query plan’s signature is quite different to what INFORMATION_SCHEMA.COLUMNS. For example, [TIMESTAMP, BIGINT, VARCHAR] from INFORMATION_SCHEMA is [LONG, LONG, STRING] from query plan’s signature.

Is this intentional? Is there a way for me to get the datatypes as defined in INFORMATION_SCHEMA from query plan?

Happy to share some more data if needed.