-- Copyright (c) 2014, 2019, Oracle and/or its affiliates. All rights reserved.
--
-- This program is free software; you can redistribute it and/or modify
-- it under the terms of the GNU General Public License, version 2.0,
-- as published by the Free Software Foundation.
--
-- This program is also distributed with certain software (including
-- but not limited to OpenSSL) that is licensed under separate terms,
-- as designated in a particular file or component or in included license
-- documentation.  The authors of MySQL hereby grant you an additional
-- permission to link the program and your derivative works with the
-- separately licensed software that they have included with MySQL.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU General Public License, version 2.0, for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program; if not, write to the Free Software
-- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

DROP PROCEDURE IF EXISTS ps_truncate_all_tables;

DELIMITER $$

CREATE DEFINER='mysql.sys'@'localhost' PROCEDURE ps_truncate_all_tables (
        IN in_verbose BOOLEAN
    )
    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)
'
    SQL SECURITY INVOKER
    DETERMINISTIC
    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$$

DELIMITER ;
