Hello! I am working on emulating a Postgres server and am faced with the following problem:
Postgres `pg_catalog` schema has custom types like `name`, those types can be easily mapped to calcite basic types. The problem is that several types in PG can be mapped to one calcite type (for example: `name` and `varchar` in PG are mapped to `varchar` type in calcite) but postgres has a unique id for every type. Some PG clients like Power BI require the right id for the column. Planner.validateAndGetType() returns row data type for the query, but I can not derive pg type id from this data type, because calcite data type can correspond to several PG types. One solution would be putting some extra information to RelDataType when the table structure is defined and somehow extracting it when the row type for query is inferred. I will be very grateful for your help
