Remove unneeded pg_catalog schema name

scripts-available/CDB_ColumnType.sql

@@ -3,12 +3,12 @@ CREATE OR REPLACE FUNCTION CDB_ColumnType(REGCLASS, TEXT)
 RETURNS information_schema.character_data
 AS $$
   SELECT
-    pg_catalog.format_type(a.atttypid, NULL)::information_schema.character_data data_type
+    format_type(a.atttypid, NULL)::information_schema.character_data data_type
   FROM pg_class c
-       LEFT JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid
+       LEFT JOIN pg_attribute a ON a.attrelid = c.oid
   WHERE c.oid = $1::oid
   AND a.attname = $2
-  AND a.attstattarget = -1;
+  AND a.attstattarget < 0; -- exclude system columns
 $$ LANGUAGE SQL;
 
 -- This is to migrate from pre-0.2.0 version