drop_range_partition(): check that it's indeed a RANGE partition, allow unprivileged user to change GUC variable pg_pathman_enable_partition_filter

Author: funbringer

README.md

@@ -533,7 +533,7 @@ SELECT detach_range_partition('journal_archive');
 ```
 
 Here's an example of the query performing filtering by partitioning key:
-```
+```plpgsql
 SELECT * FROM journal WHERE dt >= '2015-06-01' AND dt < '2015-06-03';
    id   |         dt          | level |               msg
 --------+---------------------+-------+----------------------------------

range.sql

@@ -582,7 +582,7 @@ BEGIN
 
 	/* Check if this is a RANGE partition */
 	IF v_part_type != 2 THEN
-		RAISE EXCEPTION 'specified partition isn''t RANGE partition';
+		RAISE EXCEPTION '"%" is not a RANGE partition', p_partition::TEXT;
 	END IF;
 
 	v_atttype = @extschema@.get_attribute_type(v_parent, v_attname);
@@ -1036,11 +1036,22 @@ DECLARE
 	part_name		TEXT;
 	v_relkind		CHAR;
 	v_rows			BIGINT;
+	v_part_type		INTEGER;
 
 BEGIN
 	parent_relid := @extschema@.get_parent_of_partition(p_partition);
 	part_name := p_partition::TEXT; /* save the name to be returned */
 
+	SELECT parttype
+	FROM @extschema@.pathman_config
+	WHERE partrel = parent_relid
+	INTO v_part_type;
+
+	/* Check if this is a RANGE partition */
+	IF v_part_type != 2 THEN
+		RAISE EXCEPTION '"%" is not a RANGE partition', p_partition::TEXT;
+	END IF;
+
 	/* Acquire lock on parent */
 	PERFORM @extschema@.lock_partitioned_relation(parent_relid);
 

src/partition_filter.c

@@ -92,7 +92,7 @@ init_partition_filter_static_data(void)
 							 NULL,
 							 &pg_pathman_enable_partition_filter,
 							 true,
-							 PGC_SUSET,
+							 PGC_USERSET,
 							 0,
 							 NULL,
 							 NULL,

src/pl_funcs.c

@@ -173,7 +173,7 @@ get_parent_of_partition_pl(PG_FUNCTION_ARGS)
 		PG_RETURN_OID(parent);
 	else
 	{
-		elog(ERROR, "\%s\" is not pg_pathman's partition",
+		elog(ERROR, "\"%s\" is not a partition",
 			 get_rel_name_or_relid(partition));
 
 		PG_RETURN_NULL();