improved function drop_partitions()

Author: funbringer

init.sql

@@ -581,23 +581,22 @@ DECLARE
 	v_rec			RECORD;
 	v_rows			BIGINT;
 	v_part_count	INTEGER := 0;
-	conf_num_del	INTEGER;
+	conf_num		INTEGER;
 	v_relkind		CHAR;
 
 BEGIN
 	PERFORM @extschema@.validate_relname(parent_relid);
 
-	/* Drop trigger first */
-	PERFORM @extschema@.drop_triggers(parent_relid);
+	/* Acquire data modification lock */
+	PERFORM @extschema@.prevent_relation_modification(parent_relid);
 
-	WITH config_num_deleted AS (DELETE FROM @extschema@.pathman_config
-								WHERE partrel = parent_relid
-								RETURNING *)
-	SELECT count(*) from config_num_deleted INTO conf_num_del;
+	/* First, drop all triggers */
+	PERFORM @extschema@.drop_triggers(parent_relid);
 
-	DELETE FROM @extschema@.pathman_config_params WHERE partrel = parent_relid;
+	SELECT count(*) FROM @extschema@.pathman_config
+	WHERE partrel = parent_relid INTO conf_num;
 
-	IF conf_num_del = 0 THEN
+	IF conf_num = 0 THEN
 		RAISE EXCEPTION 'relation "%" has no partitions', parent_relid::TEXT;
 	END IF;
 
@@ -621,8 +620,8 @@ BEGIN
 		INTO v_relkind;
 
 		/*
-		 * Determine the kind of child relation. It can be either regular
-		 * table (r) or foreign table (f). Depending on relkind we use
+		 * Determine the kind of child relation. It can be either a regular
+		 * table (r) or a foreign table (f). Depending on relkind we use
 		 * DROP TABLE or DROP FOREIGN TABLE.
 		 */
 		IF v_relkind = 'f' THEN
@@ -634,6 +633,10 @@ BEGIN
 		v_part_count := v_part_count + 1;
 	END LOOP;
 
+	/* Finally delete both config entries */
+	DELETE FROM @extschema@.pathman_config WHERE partrel = parent_relid;
+	DELETE FROM @extschema@.pathman_config_params WHERE partrel = parent_relid;
+
 	RETURN v_part_count;
 END
 $$ LANGUAGE plpgsql