Optimize funcion CDB_COlumnType

scripts-available/CDB_ColumnType.sql

@@ -2,15 +2,13 @@
 CREATE OR REPLACE FUNCTION CDB_ColumnType(REGCLASS, TEXT)
 RETURNS information_schema.character_data
 AS $$
-
-    SELECT c.data_type
-      FROM information_schema.columns c, pg_class _tn, pg_namespace _sn
-      WHERE table_name = _tn.relname
-        AND table_schema = _sn.nspname
-        AND column_name = $2
-        AND _tn.oid = $1::oid
-        AND _sn.oid = _tn.relnamespace;
-         
+  SELECT
+    pg_catalog.format_type(a.atttypid, NULL)::information_schema.character_data data_type
+  FROM pg_class c
+       LEFT JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid
+  WHERE c.oid = $1::oid
+  AND a.attname = $2
+  AND a.attstattarget = -1;
 $$ LANGUAGE SQL;
 
 -- This is to migrate from pre-0.2.0 version