Use underlying type of domain type when defined

This fixes issues with primary keys being defined using domain types, and deselected by default.

E.g. for a domain type `email_domain` with base type `text`, the `data_type` column will now be `text` rather than `email_domain`.

Author: Limess

tap_postgres/discovery_utils.py

@@ -64,7 +64,6 @@ def produce_table_info(conn, filter_schemas=None, tables: Optional[List[str]] =
     with conn.cursor(cursor_factory=psycopg2.extras.DictCursor, name='stitch_cursor') as cur:
         cur.itersize = post_db.CURSOR_ITER_SIZE
         table_info = {}
-        # SELECT CASE WHEN $2.typtype = 'd' THEN $2.typbasetype ELSE $1.atttypid END
         sql = """
 SELECT
   pg_class.reltuples::BIGINT                            AS approximate_row_count,
@@ -73,7 +72,7 @@ def produce_table_info(conn, filter_schemas=None, tables: Optional[List[str]] =
   pg_class.relname                                      AS table_name,
   attname                                               AS column_name,
   i.indisprimary                                        AS primary_key,
-  format_type(a.atttypid, NULL::integer)                AS data_type,
+  format_type(CASE WHEN pgt.typtype = 'd' THEN pgt.typbasetype ELSE a.atttypid END, NULL::integer) AS data_type,
   information_schema._pg_char_max_length(CASE WHEN COALESCE(subpgt.typtype, pgt.typtype) = 'd'
                                               THEN COALESCE(subpgt.typbasetype, pgt.typbasetype) ELSE COALESCE(subpgt.oid, pgt.oid)
                                           END,