fix(db_pg): Strip index size from each field

frappe/database/postgres/database.py

@@ -261,11 +261,11 @@ class PostgresDatabase(Database):
 	def add_index(self, doctype, fields, index_name=None):
 		"""Creates an index with given fields if not already created.
 		Index name will be `fieldname1_fieldname2_index`"""
+		table_name = get_table_name(doctype)
 		index_name = index_name or self.get_index_name(fields)
-		table_name = 'tab' + doctype
-		fields_str = re.sub(r"\(.*\)", "", '", "'.join(fields))
-		self.commit()
-		self.sql(f'CREATE INDEX IF NOT EXISTS "{index_name}" ON `{table_name}`("{fields_str}")')
+		fields_str = '", "'.join(re.sub(r"\(.*\)", "", field) for field in fields)
+
+		self.sql_ddl(f'CREATE INDEX IF NOT EXISTS "{index_name}" ON `{table_name}` ("{fields_str}")')
 
 	def add_unique(self, doctype, fields, constraint_name=None):
 		if isinstance(fields, str):