-- 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

--
-- View: x$wait_classes_global_by_avg_latency
-- 
-- Lists the top wait classes by average latency, ignoring idle (this may be very large).
--
-- mysql> select * from x$wait_classes_global_by_avg_latency;
-- +-------------------+---------+-------------------+-------------+--------------------+------------------+
-- | event_class       | total   | total_latency     | min_latency | avg_latency        | max_latency      |
-- +-------------------+---------+-------------------+-------------+--------------------+------------------+
-- | idle              |    4331 | 16044682716000000 |     2000000 | 3704613880397.1369 | 1593550454000000 |
-- | wait/io/file      |   23037 |    20856702551880 |           0 |     905356711.0249 |     350700491310 |
-- | wait/io/table     |  224924 |      719670285750 |      116870 |       3199615.3623 |     208579012460 |
-- | wait/lock/table   |    6972 |        3674766030 |      109330 |        527074.8752 |          8855730 |
-- | wait/synch/rwlock |   11916 |        1273279800 |       37700 |        106854.6324 |          6838780 |
-- | wait/synch/mutex  | 1031881 |       80464286240 |       56550 |         77978.2613 |       2590408470 |
-- +-------------------+---------+-------------------+-------------+--------------------+------------------+
--

CREATE OR REPLACE
  ALGORITHM = TEMPTABLE
  DEFINER = 'mysql.sys'@'localhost'
  SQL SECURITY INVOKER 
VIEW x$wait_classes_global_by_avg_latency (
  event_class,
  total,
  total_latency,
  min_latency,
  avg_latency,
  max_latency
) AS
SELECT SUBSTRING_INDEX(event_name,'/', 3) AS event_class,
       SUM(COUNT_STAR) AS total,
       SUM(sum_timer_wait) AS total_latency,
       MIN(min_timer_wait) AS min_latency,
       IFNULL(SUM(sum_timer_wait) / NULLIF(SUM(COUNT_STAR), 0), 0) AS avg_latency,
       MAX(max_timer_wait) AS max_latency
  FROM performance_schema.events_waits_summary_global_by_event_name
 WHERE sum_timer_wait > 0
   AND event_name != 'idle'
 GROUP BY event_class
 ORDER BY IFNULL(SUM(sum_timer_wait) / NULLIF(SUM(COUNT_STAR), 0), 0) DESC;

