create
    definer = `mysql.sys`@localhost procedure sys.ps_truncate_all_tables(IN in_verbose tinyint(1)) comment '
Description
-----------

Truncates all summary tables within Performance Schema, 
resetting all aggregated instrumentation as a snapshot.

Parameters
-----------

in_verbose (BOOLEAN):
  Whether to print each TRUNCATE statement before running

Example
-----------

mysql> CALL sys.ps_truncate_all_tables(false);
+---------------------+
| summary             |
+---------------------+
| Truncated 44 tables |
+---------------------+
1 row in set (0.10 sec)

Query OK, 0 rows affected (0.10 sec)
' deterministic sql security invoker modifies sql data
BEGIN
    DECLARE v_done INT DEFAULT FALSE;
    DECLARE v_total_tables INT DEFAULT 0;
    DECLARE v_ps_table VARCHAR(64);
    DECLARE ps_tables CURSOR FOR
        SELECT table_name 
          FROM INFORMATION_SCHEMA.TABLES 
         WHERE table_schema = 'performance_schema' 
           AND (table_name LIKE '%summary%' 
            OR table_name LIKE '%history%');
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET v_done = TRUE;
    OPEN ps_tables;
    ps_tables_loop: LOOP
        FETCH ps_tables INTO v_ps_table;
        IF v_done THEN
          LEAVE ps_tables_loop;
        END IF;
        SET @truncate_stmt := CONCAT('TRUNCATE TABLE performance_schema.', v_ps_table);
        IF in_verbose THEN
            SELECT CONCAT('Running: ', @truncate_stmt) AS status;
        END IF;
        PREPARE truncate_stmt FROM @truncate_stmt;
        EXECUTE truncate_stmt;
        DEALLOCATE PREPARE truncate_stmt;
        SET v_total_tables = v_total_tables + 1;
    END LOOP;
    CLOSE ps_tables;
    SELECT CONCAT('Truncated ', v_total_tables, ' tables') AS summary;
END;