/* Copyright (c) 2014, 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 as published by
   the Free Software Foundation; version 2 of the License.

   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 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: statements_with_full_table_scans
 *
 * Lists all normalized statements that use have done a full table scan
 * ordered by number the percentage of times a full scan was done,
 * then by the statement latency.
 *
 * mysql> select * from statements_with_full_table_scans limit 1\G
 * *************************** 1. row ***************************
 *                    query: SELECT * FROM `schema_tables_w ... ex_usage` . `COUNT_READ` DESC
 *                       db: sys
 *               exec_count: 1
 *            total_latency: 88.20 ms
 *      no_index_used_count: 1
 * no_good_index_used_count: 0
 *        no_index_used_pct: 100
 *                rows_sent: 0
 *            rows_examined: 1501
 *            rows_sent_avg: 0
 *        rows_examined_avg: 1501
 *               first_seen: 2014-03-07 13:58:20
 *                last_seen: 2014-03-07 13:58:20
 *                   digest: 64baecd5c1e1e1651a6b92e55442a288
 *
 */

CREATE OR REPLACE
  ALGORITHM = MERGE
  DEFINER = 'root'@'localhost'
  SQL SECURITY INVOKER 
VIEW statements_with_full_table_scans (
  query,
  db,
  exec_count,
  total_latency,
  no_index_used_count,
  no_good_index_used_count,
  no_index_used_pct,
  rows_sent,
  rows_examined,
  rows_sent_avg,
  rows_examined_avg,
  first_seen,
  last_seen,
  digest
) AS
SELECT sys.format_statement(DIGEST_TEXT) AS query,
       SCHEMA_NAME as db,
       COUNT_STAR AS exec_count,
       sys.format_time(SUM_TIMER_WAIT) AS total_latency,
       SUM_NO_INDEX_USED AS no_index_used_count,
       SUM_NO_GOOD_INDEX_USED AS no_good_index_used_count,
       ROUND(IFNULL(SUM_NO_INDEX_USED / NULLIF(COUNT_STAR, 0), 0) * 100) AS no_index_used_pct,
       SUM_ROWS_SENT AS rows_sent,
       SUM_ROWS_EXAMINED AS rows_examined,
       ROUND(SUM_ROWS_SENT/COUNT_STAR) AS rows_sent_avg,
       ROUND(SUM_ROWS_EXAMINED/COUNT_STAR) AS rows_examined_avg,
       FIRST_SEEN as first_seen,
       LAST_SEEN as last_seen,
       DIGEST AS digest
  FROM performance_schema.events_statements_summary_by_digest
 WHERE SUM_NO_INDEX_USED > 0
    OR SUM_NO_GOOD_INDEX_USED > 0
 ORDER BY no_index_used_pct DESC, total_latency DESC;

/*
 * View: x$statements_with_full_table_scans
 *
 * Lists all normalized statements that use have done a full table scan
 * ordered by number the percentage of times a full scan was done,
 * then by the statement latency.
 *
 * mysql> select * from x$statements_with_full_table_scans limit 1\G
 * *************************** 1. row ***************************
 *                    query: SELECT * FROM `schema_object_overview` SELECT `information_schema` . `routines` . `ROUTINE_SCHEMA` // truncated
 *                       db: sys
 *               exec_count: 2
 *            total_latency: 16751388791000
 *      no_index_used_count: 2
 * no_good_index_used_count: 0
 *        no_index_used_pct: 100
 *                rows_sent: 84
 *            rows_examined: 20012
 *            rows_sent_avg: 42
 *        rows_examined_avg: 10006
 *               first_seen: 2014-03-07 13:13:41
 *                last_seen: 2014-03-07 13:13:48
 *                   digest: 54f9bd520f0bbf15db0c2ed93386bec9
 *
 */

CREATE OR REPLACE
  ALGORITHM = MERGE
  DEFINER = 'root'@'localhost'
  SQL SECURITY INVOKER 
VIEW x$statements_with_full_table_scans (
  query,
  db,
  exec_count,
  total_latency,
  no_index_used_count,
  no_good_index_used_count,
  no_index_used_pct,
  rows_sent,
  rows_examined,
  rows_sent_avg,
  rows_examined_avg,
  first_seen,
  last_seen,
  digest
) AS
SELECT DIGEST_TEXT AS query,
       SCHEMA_NAME as db,
       COUNT_STAR AS exec_count,
       SUM_TIMER_WAIT AS total_latency,
       SUM_NO_INDEX_USED AS no_index_used_count,
       SUM_NO_GOOD_INDEX_USED AS no_good_index_used_count,
       ROUND(IFNULL(SUM_NO_INDEX_USED / NULLIF(COUNT_STAR, 0), 0) * 100) AS no_index_used_pct,
       SUM_ROWS_SENT AS rows_sent,
       SUM_ROWS_EXAMINED AS rows_examined,
       ROUND(SUM_ROWS_SENT/COUNT_STAR) AS rows_sent_avg,
       ROUND(SUM_ROWS_EXAMINED/COUNT_STAR) AS rows_examined_avg,
       FIRST_SEEN as first_seen,
       LAST_SEEN as last_seen,
       DIGEST AS digest
  FROM performance_schema.events_statements_summary_by_digest
 WHERE SUM_NO_INDEX_USED > 0
    OR SUM_NO_GOOD_INDEX_USED > 0
 ORDER BY no_index_used_pct DESC, total_latency DESC;
