SYSスキーマのstatement_analysisとperformance_schemaのevents_statements_historyを利用して、MySQLで簡単にSQLのパフォーマンス確認。
statement_analysis / x$statement_analysis
Description:
Lists a normalized statement view with aggregated statistics,
mimics the MySQL Enterprise Monitor Query Analysis view, ordered by the total execution time per normalized statement
https://github.com/mysql/mysql-sys
events_statements_history
events_statements_history テーブルには、スレッドごとの最新の N ステートメントイベントが格納されます。
N の値はサーバー起動時に自動サイズ設定されます。テーブルサイズを明示的に設定するには、サーバー起動時にperformance_schema_events_statements_history_sizeシステム変数を設定します。
ステートメントイベントは終了するまでテーブルに追加されません。新しいイベントが追加されたときに、テーブルがいっぱいである場合、古いイベントが破棄されます。
https://dev.mysql.com/doc/refman/5.6/ja/events-statements-history-table.html
以下、幾つかテストしてみました。データも十分に入っていないので、十分なテストでは無いですが、
挙動は把握出来るかと思いますので、実際の検証環境で確認して見てください。
【1】 JSONデータのFULLスキャンの状況確認
1) 先ずは、既存のsys.statement_analysisの状況を確認してみます。
root@localhost [sys]> select now(),query,db,full_scan,tmp_tables,tmp_disk_tables,sort_merge_passes from sys.statement_analysis; +---------------------+-------------------------------------------------------------------+--------------------+-----------+------------+-----------------+-------------------+ | now() | query | db | full_scan | tmp_tables | tmp_disk_tables | sort_merge_passes | +---------------------+-------------------------------------------------------------------+--------------------+-----------+------------+-----------------+-------------------+ | 2016-06-03 22:16:47 | SHOW TABLES | sys | * | 1 | 0 | 0 | | 2016-06-03 22:16:47 | SELECT `sys` . `format_stateme ... cy` , `sys` . `format_time` ( | sys | * | 0 | 0 | 0 | | 2016-06-03 22:16:47 | SHOW SCHEMAS | performance_schema | * | 1 | 0 | 0 | | 2016-06-03 22:16:47 | SHOW TABLES | performance_schema | * | 1 | 0 | 0 | | 2016-06-03 22:16:47 | SELECT SYSTEM_USER , HOST , `d ... != ? AND `state` NOT IN (...) | performance_schema | * | 2 | 2 | 0 | | 2016-06-03 22:16:47 | SHOW SCHEMAS | sys | * | 1 | 0 | 0 | | 2016-06-03 22:16:47 | SELECT SCHEMA ( ) | performance_schema | | 0 | 0 | 0 | | 2016-06-03 22:16:47 | SELECT SCHEMA ( ) | NULL | | 0 | 0 | 0 | | 2016-06-03 22:16:47 | SELECT SYSTEM_USER ( ) | NULL | | 0 | 0 | 0 | | 2016-06-03 22:16:47 | SELECT @@`version_comment` LIMIT ? | NULL | | 0 | 0 | 0 | +---------------------+-------------------------------------------------------------------+--------------------+-----------+------------+-----------------+-------------------+ 10 rows in set (0.00 sec) root@localhost [sys]>
2) こちらのJSONデータを確認するQueryを実行してみます。
echo "INDEXの無いテーブルに対するSELECTを、TEXT型とJSONデータ型で比較します。" echo "SELECT distinct json_extract(feature,'$.type') as feature FROM 各テーブル" echo "" echo "【TEXT型】" time /usr/local/mysql/bin/mysql -u demo_user -ppassword -e "SELECT distinct json_extract(feature,'$.type') as feature FROM NEW57.features_txt;" echo "" echo "【JSON型】" time /usr/local/mysql/bin/mysql -u demo_user -ppassword -e "SELECT distinct json_extract(feature,'$.type') as feature FROM NEW57.features_json;"
3) 実行 (やっぱりJSONデータ型は、TEXT型と比較するとバイナリーで早いですね：206,000件のデータ参照）
[admin@misc01 SOD2015]$ ./json_and_text_without_index.sh INDEXの無いテーブルに対するSELECTを、TEXT型とJSONデータ型で比較します。 SELECT distinct json_extract(feature,'$.type') as feature FROM 各テーブル 【TEXT型】 mysql: [Warning] Using a password on the command line interface can be insecure. +-----------+ | feature | +-----------+ | "Feature" | +-----------+ real 0m8.147s user 0m0.007s sys 0m0.004s 【JSON型】 mysql: [Warning] Using a password on the command line interface can be insecure. +-----------+ | feature | +-----------+ | "Feature" | +-----------+ real 0m1.379s user 0m0.009s sys 0m0.005s [admin@misc01 SOD2015]$
4) 実行結果
INDEXも無い、206,000件のデータなのでどちらも、FULLスキャン,temp table,そしてディスクのtemp tableへ変換されてますね。
root@localhost [sys]> select now(),query,db,full_scan,tmp_tables,tmp_disk_tables,sort_merge_passes from sys.statement_analysis; +---------------------+-------------------------------------------------------------------+--------------------+-----------+------------+-----------------+-------------------+ | now() | query | db | full_scan | tmp_tables | tmp_disk_tables | sort_merge_passes | +---------------------+-------------------------------------------------------------------+--------------------+-----------+------------+-----------------+-------------------+ | 2016-06-03 22:19:02 | SELECT DISTINCTROW `json_extra ... FROM `NEW57` . `features_txt` | NULL | * | 1 | 1 | 0 | ※ | 2016-06-03 22:19:02 | SELECT DISTINCTROW `json_extra ... ROM `NEW57` . `features_json` | NULL | * | 1 | 1 | 0 | ※ | 2016-06-03 22:19:02 | SHOW TABLES | sys | * | 2 | 0 | 0 | | 2016-06-03 22:19:02 | SELECT `sys` . `format_stateme ... cy` , `sys` . `format_time` ( | sys | * | 0 | 0 | 0 | | 2016-06-03 22:19:02 | SHOW SCHEMAS | performance_schema | * | 1 | 0 | 0 | | 2016-06-03 22:19:02 | SELECT SYSTEM_USER ( ) | NULL | | 0 | 0 | 0 | | 2016-06-03 22:19:02 | SHOW SCHEMAS | sys | * | 2 | 0 | 0 | | 2016-06-03 22:19:02 | SHOW TABLES | performance_schema | * | 1 | 0 | 0 | | 2016-06-03 22:19:02 | SELECT SYSTEM_USER , HOST , `d ... != ? AND `state` NOT IN (...) | performance_schema | * | 2 | 2 | 0 | | 2016-06-03 22:19:02 | SELECT @@`version_comment` LIMIT ? | NULL | | 0 | 0 | 0 | | 2016-06-03 22:19:02 | SELECT SCHEMA ( ) | NULL | | 0 | 0 | 0 | | 2016-06-03 22:19:02 | SELECT SCHEMA ( ) | performance_schema | | 0 | 0 | 0 | +---------------------+-------------------------------------------------------------------+--------------------+-----------+------------+-----------------+-------------------+ 12 rows in set (0.01 sec) root@localhost [sys]>
【2】 JSONデータにGENERATE COLUMN(生成列)でINDEXを付与した場合の状況確認
1) 実行スクリプト
echo "JSONデータ型のサンプルを入れたテーブル" /usr/local/mysql/bin/mysql -u demo_user -ppassword -e "select * from NEW57.features where feature_street = '\"MARKET\"' limit 1\G" read -p "Press [Enter] key to resume." echo "JSONデータ型とGenerated Columnを利用したテーブル" /usr/local/mysql/bin/mysql -u demo_user -ppassword -e "show create table NEW57.features\G" read -p "Press [Enter] key to resume." echo "JSONドキュメントに対して、INDEX検索が利用出来るか確認 -> where feature_street = '\"MARKET\"'" /usr/local/mysql/bin/mysql -u demo_user -ppassword -e "explain select feature from NEW57.features where feature_street = '\"MARKET\"'\G"
2) 実行と実行結果
[admin@misc01 SOD2015]$ ./json_and_generated_column_index.sh
JSONデータ型のサンプルを入れたテーブル
mysql: [Warning] Using a password on the command line interface can be insecure.
*************************** 1. row ***************************
id: 12250
feature: {"type": "Feature", "geometry": {"type": "Polygon", "coordinates": [[[-122.39836263491878, 37.79189388899312, 0], [-122.39845248797837, 37.79233030084018, 0], [-122.39768507706792, 37.7924280850133, 0], [-122.39836263491878, 37.79189388899312, 0]]]}, "properties": {"TO_ST": "388", "BLKLOT": "0265003", "STREET": "MARKET", "FROM_ST": "388", "LOT_NUM": "003", "ST_TYPE": "ST", "ODD_EVEN": "E", "BLOCK_NUM": "0265", "MAPBLKLOT": "0265003"}}
feature_type: "Feature"
feature_street: "MARKET"
Press [Enter] key to resume.
JSONデータ型とGenerated Columnを利用したテーブル
mysql: [Warning] Using a password on the command line interface can be insecure.
*************************** 1. row ***************************
Table: features
Create Table: CREATE TABLE `features` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`feature` json NOT NULL,
`feature_type` varchar(30) GENERATED ALWAYS AS (json_extract(`feature`,'$.type')) VIRTUAL,
`feature_street` varchar(30) GENERATED ALWAYS AS (json_extract(`feature`,'$.properties.STREET')) VIRTUAL,
PRIMARY KEY (`id`),
KEY `idx_feature_type` (`feature_type`),
KEY `idx_feature_street` (`feature_street`)
) ENGINE=InnoDB AUTO_INCREMENT=206561 DEFAULT CHARSET=utf8mb4
Press [Enter] key to resume.
JSONドキュメントに対して、INDEX検索が利用出来るか確認 -> where feature_street = '"MARKET"'
mysql: [Warning] Using a password on the command line interface can be insecure.
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: features
partitions: NULL
type: ref
possible_keys: idx_feature_street
key: idx_feature_street
key_len: 123
ref: const
rows: 808
filtered: 100.00
Extra: NULL
[admin@misc01 SOD2015]$
3) 実行後のsys.statement_analysisを確認すると、full_scanでも無く,temp tableでの処理も無いことが確認出来る。
root@localhost [sys]> select now(),query,db,full_scan,tmp_tables,tmp_disk_tables,sort_merge_passes from sys.statement_analysis; +---------------------+-------------------------------------------------------------------+--------------------+-----------+------------+-----------------+-------------------+ | now() | query | db | full_scan | tmp_tables | tmp_disk_tables | sort_merge_passes | +---------------------+-------------------------------------------------------------------+--------------------+-----------+------------+-----------------+-------------------+ | 2016-06-03 22:22:03 | SELECT DISTINCTROW `json_extra ... FROM `NEW57` . `features_txt` | NULL | * | 1 | 1 | 0 | | 2016-06-03 22:22:03 | SELECT DISTINCTROW `json_extra ... ROM `NEW57` . `features_json` | NULL | * | 1 | 1 | 0 | | 2016-06-03 22:22:03 | SELECT * FROM `NEW57` . `featu ... _extract` ( `feature` , ? ) ) | NULL | | 0 | 0 | 0 | ※ | 2016-06-03 22:22:03 | SHOW TABLES | sys | * | 3 | 0 | 0 | | 2016-06-03 22:22:03 | SELECT `sys` . `format_stateme ... cy` , `sys` . `format_time` ( | sys | * | 0 | 0 | 0 | | 2016-06-03 22:22:03 | SHOW SCHEMAS | performance_schema | * | 1 | 0 | 0 | | 2016-06-03 22:22:03 | SELECT SYSTEM_USER ( ) | NULL | | 0 | 0 | 0 | | 2016-06-03 22:22:03 | SHOW SCHEMAS | sys | * | 3 | 0 | 0 | | 2016-06-03 22:22:03 | SELECT @@`version_comment` LIMIT ? | NULL | | 0 | 0 | 0 | | 2016-06-03 22:22:03 | SHOW TABLES | performance_schema | * | 1 | 0 | 0 | | 2016-06-03 22:22:03 | SELECT SYSTEM_USER , HOST , `d ... != ? AND `state` NOT IN (...) | performance_schema | * | 2 | 2 | 0 | | 2016-06-03 22:22:03 | EXPLAIN SELECT `feature` FROM ... _extract` ( `feature` , ? ) ) | NULL | | 0 | 0 | 0 | | 2016-06-03 22:22:03 | SHOW CREATE TABLE `NEW57` . `f ... _extract` ( `feature` , ? ) ) | NULL | | 0 | 0 | 0 | | 2016-06-03 22:22:03 | SELECT SCHEMA ( ) | NULL | | 0 | 0 | 0 | | 2016-06-03 22:22:03 | SELECT SCHEMA ( ) | performance_schema | | 0 | 0 | 0 | +---------------------+-------------------------------------------------------------------+--------------------+-----------+------------+-----------------+-------------------+ 15 rows in set (0.00 sec) root@localhost [sys]>
【3】 ここからは、MySQLのオフィシャルサンプルDB(World)を利用してMySQLの挙動とパフォーマンスを確認してみます。
パターン1) Country STRAIGHT_JOIN CountryLanguage ON CountryLanguage.CountryCode
root@localhost [sys]> select now(),query,db,full_scan,tmp_tables,tmp_disk_tables,sort_merge_passes from sys.statement_analysis where db = 'world'; +---------------------+---------------+-------+-----------+------------+-----------------+-------------------+ | now() | query | db | full_scan | tmp_tables | tmp_disk_tables | sort_merge_passes | +---------------------+---------------+-------+-----------+------------+-----------------+-------------------+ | 2016-06-03 22:25:41 | SHOW TABLES | world | * | 2 | 0 | 0 | | 2016-06-03 22:25:41 | SHOW SCHEMAS | world | * | 1 | 0 | 0 | +---------------------+---------------+-------+-----------+------------+-----------------+-------------------+ 2 rows in set (0.01 sec) root@localhost [sys]> root@localhost [world]> SELECT Language, COUNT(1) FROM Country STRAIGHT_JOIN CountryLanguage ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE; +---------------------------+----------+ | Language | COUNT(1) | +---------------------------+----------+ | Abhyasi | 1 | | Acholi | 1 | | Adja | 1 | <SNIP> | Zhuang | 1 | | Zulu | 3 | | [South]Mande | 1 | +---------------------------+----------+ 457 rows in set (0.04 sec) root@localhost [world]> root@localhost [sys]> select now(),query,db,full_scan,tmp_tables,tmp_disk_tables,sort_merge_passes from sys.statement_analysis where db = 'world'; +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ | now() | query | db | full_scan | tmp_tables | tmp_disk_tables | sort_merge_passes | +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ | 2016-06-03 22:25:52 | SELECT LANGUAGE , COUNT (?) FR ... OM `City` ) GROUP BY LANGUAGE | world | * | 1 | 0 | 0 |(1回目) | 2016-06-03 22:25:52 | SHOW TABLES | world | * | 2 | 0 | 0 | | 2016-06-03 22:25:52 | SHOW SCHEMAS | world | * | 1 | 0 | 0 | +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ 3 rows in set (0.00 sec) root@localhost [sys]>
上記、Queryの実行プランと実行時間を確認してみます。
root@localhost [world]> explain SELECT Language, COUNT(1) FROM Country STRAIGHT_JOIN CountryLanguage ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE; +----+-------------+-----------------+------------+--------+---------------------+-------------+---------+-----------------------+------+----------+----------------------------------------------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra | +----+-------------+-----------------+------------+--------+---------------------+-------------+---------+-----------------------+------+----------+----------------------------------------------+ | 1 | SIMPLE | Country | NULL | ALL | PRIMARY | NULL | NULL | NULL | 239 | 100.00 | Using where; Using temporary; Using filesort | | 1 | SIMPLE | City | NULL | eq_ref | PRIMARY | PRIMARY | 4 | world.Country.Capital | 1 | 100.00 | Using index | | 1 | SIMPLE | CountryLanguage | NULL | ref | PRIMARY,CountryCode | CountryCode | 3 | world.Country.Code | 4 | 100.00 | Using index | +----+-------------+-----------------+------------+--------+---------------------+-------------+---------+-----------------------+------+----------+----------------------------------------------+ 3 rows in set, 1 warning (0.00 sec) root@localhost [world]> root@localhost [sys]> select SQL_TEXT,(timer_wait)/1000000000.0 "t (ms)",ROWS_EXAMINED from performance_schema.events_statements_history order by TIMER_START desc limit 10; +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+---------------+ | SQL_TEXT | t (ms) | ROWS_EXAMINED | +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+---------------+ | SELECT Language, COUNT(1) FROM Country STRAIGHT_JOIN CountryLanguage ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE | 7.3615 | 2368 |(1回目) | select SQL_TEXT,(timer_wait)/1000000000.0 "t (ms)",ROWS_EXAMINED from performance_schema.events_statements_history order by TIMER_START desc limit 10 | 0.5577 | 2 | | truncate table performance_schema.events_statements_history | 0.9153 | 0 | +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+---------------+ 3 rows in set (0.01 sec) root@localhost [sys]>
パターン2) CountryLanguage STRAIGHT_JOIN Country ON CountryLanguage.CountryCode = Country.Code
root@localhost [sys]> select now(),query,db,full_scan,tmp_tables,tmp_disk_tables,sort_merge_passes from sys.statement_analysis where db = 'world'; +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ | now() | query | db | full_scan | tmp_tables | tmp_disk_tables | sort_merge_passes | +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ | 2016-06-03 22:28:15 | SELECT LANGUAGE , COUNT (?) FR ... OM `City` ) GROUP BY LANGUAGE | world | * | 1 | 0 | 0 | | 2016-06-03 22:28:15 | EXPLAIN SELECT LANGUAGE , COUN ... OM `City` ) GROUP BY LANGUAGE | world | * | 1 | 0 | 0 | | 2016-06-03 22:28:15 | SHOW TABLES | world | * | 2 | 0 | 0 | | 2016-06-03 22:28:15 | SHOW SCHEMAS | world | * | 1 | 0 | 0 | +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ 4 rows in set (0.01 sec) root@localhost [sys]> root@localhost [world]> SELECT Language, COUNT(1) FROM CountryLanguage STRAIGHT_JOIN Country ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE; +---------------------------+----------+ | Language | COUNT(1) | +---------------------------+----------+ | Abhyasi | 1 | | Acholi | 1 | | Adja | 1 | <SNIP> | Zhuang | 1 | | Zulu | 3 | | [South]Mande | 1 | +---------------------------+----------+ 457 rows in set (0.01 sec) root@localhost [sys]> select now(),query,db,full_scan,tmp_tables,tmp_disk_tables,sort_merge_passes from sys.statement_analysis where db = 'world'; +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ | now() | query | db | full_scan | tmp_tables | tmp_disk_tables | sort_merge_passes | +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ | 2016-06-03 22:29:13 | SELECT LANGUAGE , COUNT (?) FR ... OM `City` ) GROUP BY LANGUAGE | world | * | 1 | 0 | 0 |(1回目) | 2016-06-03 22:29:13 | SELECT LANGUAGE , COUNT (?) FR ... OM `City` ) GROUP BY LANGUAGE | world | | 1 | 0 | 0 |(2回目) | 2016-06-03 22:29:13 | EXPLAIN SELECT LANGUAGE , COUN ... OM `City` ) GROUP BY LANGUAGE | world | * | 1 | 0 | 0 | | 2016-06-03 22:29:13 | SHOW TABLES | world | * | 2 | 0 | 0 | | 2016-06-03 22:29:13 | SHOW SCHEMAS | world | * | 1 | 0 | 0 | +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ 5 rows in set (0.01 sec) root@localhost [sys]>
上記、Queryの実行プランと実行時間を確認してみます。
行数は、多いですがFULL SCANは発生していません、また時間も若干早いです。（但し、何回も実施していないので確かではありません、但しこのサイズではそれ程大きく変わらない事は確かです。）
root@localhost [world]> explain SELECT Language, COUNT(1) FROM CountryLanguage STRAIGHT_JOIN Country ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE; +----+-------------+-----------------+------------+--------+---------------------+-------------+---------+-----------------------------------+------+----------+----------------------------------------------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra | +----+-------------+-----------------+------------+--------+---------------------+-------------+---------+-----------------------------------+------+----------+----------------------------------------------+ | 1 | SIMPLE | CountryLanguage | NULL | index | PRIMARY,CountryCode | CountryCode | 3 | NULL | 984 | 100.00 | Using index; Using temporary; Using filesort | | 1 | SIMPLE | Country | NULL | eq_ref | PRIMARY | PRIMARY | 3 | world.CountryLanguage.CountryCode | 1 | 100.00 | Using where | | 1 | SIMPLE | City | NULL | eq_ref | PRIMARY | PRIMARY | 4 | world.Country.Capital | 1 | 100.00 | Using index | +----+-------------+-----------------+------------+--------+---------------------+-------------+---------+-----------------------------------+------+----------+----------------------------------------------+ 3 rows in set, 1 warning (0.00 sec) root@localhost [world]> root@localhost [sys]> select SQL_TEXT,(timer_wait)/1000000000.0 "t (ms)",ROWS_EXAMINED from performance_schema.events_statements_history order by TIMER_START desc limit 10; +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+---------------+ | SQL_TEXT | t (ms) | ROWS_EXAMINED | +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+---------------+ | SELECT Language, COUNT(1) FROM CountryLanguage STRAIGHT_JOIN Country ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE | 7.0868 | 3865 |(2回目) | select SQL_TEXT,(timer_wait)/1000000000.0 "t (ms)",ROWS_EXAMINED from performance_schema.events_statements_history order by TIMER_START desc limit 10 | 1.5986 | 6 | | SELECT Language, COUNT(1) FROM Country STRAIGHT_JOIN CountryLanguage ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE | 7.3615 | 2368 |(1回目) | select SQL_TEXT,(timer_wait)/1000000000.0 "t (ms)",ROWS_EXAMINED from performance_schema.events_statements_history order by TIMER_START desc limit 10 | 0.5577 | 2 | | truncate table performance_schema.events_statements_history | 0.9153 | 0 | +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+---------------+ 5 rows in set (0.00 sec) root@localhost [sys]>
パターン3) Country JOIN CountryLanguage ON CountryLanguage.CountryCode = Country.Code
ヒント無しなので、オプティマイザー次第
root@localhost [sys]> select now(),query,db,full_scan,tmp_tables,tmp_disk_tables,sort_merge_passes from sys.statement_analysis where db = 'world'; +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ | now() | query | db | full_scan | tmp_tables | tmp_disk_tables | sort_merge_passes | +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ | 2016-06-03 22:33:16 | SELECT LANGUAGE , COUNT (?) FR ... OM `City` ) GROUP BY LANGUAGE | world | * | 1 | 0 | 0 | | 2016-06-03 22:33:16 | SELECT LANGUAGE , COUNT (?) FR ... OM `City` ) GROUP BY LANGUAGE | world | | 1 | 0 | 0 | | 2016-06-03 22:33:16 | EXPLAIN SELECT LANGUAGE , COUN ... OM `City` ) GROUP BY LANGUAGE | world | * | 1 | 0 | 0 | | 2016-06-03 22:33:16 | SHOW TABLES | world | * | 2 | 0 | 0 | | 2016-06-03 22:33:16 | EXPLAIN SELECT LANGUAGE , COUN ... OM `City` ) GROUP BY LANGUAGE | world | | 1 | 0 | 0 | | 2016-06-03 22:33:16 | SHOW SCHEMAS | world | * | 1 | 0 | 0 | +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ 6 rows in set (0.01 sec) root@localhost [sys]> root@localhost [world]> SELECT Language, COUNT(1) FROM Country JOIN CountryLanguage ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE; +---------------------------+----------+ | Language | COUNT(1) | +---------------------------+----------+ | Abhyasi | 1 | | Acholi | 1 | | Adja | 1 | <SNIP> | Zhuang | 1 | | Zulu | 3 | | [South]Mande | 1 | +---------------------------+----------+ 457 rows in set (0.01 sec) root@localhost [world]> root@localhost [sys]> select now(),query,db,full_scan,tmp_tables,tmp_disk_tables,sort_merge_passes from sys.statement_analysis where db = 'world'; +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ | now() | query | db | full_scan | tmp_tables | tmp_disk_tables | sort_merge_passes | +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ | 2016-06-03 22:33:29 | SELECT LANGUAGE , COUNT (?) FR ... OM `City` ) GROUP BY LANGUAGE | world | * | 1 | 0 | 0 |(1回目) | 2016-06-03 22:33:29 | SELECT LANGUAGE , COUNT (?) FR ... OM `City` ) GROUP BY LANGUAGE | world | | 1 | 0 | 0 |(2回目) | 2016-06-03 22:33:29 | SELECT LANGUAGE , COUNT (?) FR ... OM `City` ) GROUP BY LANGUAGE | world | * | 1 | 0 | 0 |(3回目) | 2016-06-03 22:33:29 | EXPLAIN SELECT LANGUAGE , COUN ... OM `City` ) GROUP BY LANGUAGE | world | * | 1 | 0 | 0 | | 2016-06-03 22:33:29 | SHOW TABLES | world | * | 2 | 0 | 0 | | 2016-06-03 22:33:29 | EXPLAIN SELECT LANGUAGE , COUN ... OM `City` ) GROUP BY LANGUAGE | world | | 1 | 0 | 0 | | 2016-06-03 22:33:29 | SHOW SCHEMAS | world | * | 1 | 0 | 0 | +---------------------+-------------------------------------------------------------------+-------+-----------+------------+-----------------+-------------------+ 7 rows in set (0.01 sec) root@localhost [sys]>
上記、Queryの実行プランと実行時間を確認してみます。(今回はヒントを付けてませんが、1回目と同じ実行プランになりました）
よって、EXPLAINも時間も殆ど同じです。
root@localhost [world]> explain SELECT Language, COUNT(1) FROM Country JOIN CountryLanguage ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE; +----+-------------+-----------------+------------+--------+---------------------+-------------+---------+-----------------------+------+----------+----------------------------------------------+ | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra | +----+-------------+-----------------+------------+--------+---------------------+-------------+---------+-----------------------+------+----------+----------------------------------------------+ | 1 | SIMPLE | Country | NULL | ALL | PRIMARY | NULL | NULL | NULL | 239 | 100.00 | Using where; Using temporary; Using filesort | | 1 | SIMPLE | City | NULL | eq_ref | PRIMARY | PRIMARY | 4 | world.Country.Capital | 1 | 100.00 | Using index | | 1 | SIMPLE | CountryLanguage | NULL | ref | PRIMARY,CountryCode | CountryCode | 3 | world.Country.Code | 4 | 100.00 | Using index | +----+-------------+-----------------+------------+--------+---------------------+-------------+---------+-----------------------+------+----------+----------------------------------------------+ 3 rows in set, 1 warning (0.01 sec) root@localhost [world]> root@localhost [sys]> select SQL_TEXT,(timer_wait)/1000000000.0 "t (ms)",ROWS_EXAMINED from performance_schema.events_statements_history order by TIMER_START desc limit 10; +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+---------------+ | SQL_TEXT | t (ms) | ROWS_EXAMINED | +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+---------------+ | SELECT Language, COUNT(1) FROM Country JOIN CountryLanguage ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE | 7.3393 | 2368 |(3回目) | select SQL_TEXT,(timer_wait)/1000000000.0 "t (ms)",ROWS_EXAMINED from performance_schema.events_statements_history order by TIMER_START desc limit 10 | 0.8451 | 10 | | SELECT Language, COUNT(1) FROM CountryLanguage STRAIGHT_JOIN Country ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE | 7.0868 | 3865 |(2回目) | select SQL_TEXT,(timer_wait)/1000000000.0 "t (ms)",ROWS_EXAMINED from performance_schema.events_statements_history order by TIMER_START desc limit 10 | 1.5986 | 6 | | SELECT Language, COUNT(1) FROM Country STRAIGHT_JOIN CountryLanguage ON CountryLanguage.CountryCode = Country.Code WHERE Capital IN (SELECT Id FROM City) GROUP BY LANGUAGE | 7.3615 | 2368 |(1回目) | select SQL_TEXT,(timer_wait)/1000000000.0 "t (ms)",ROWS_EXAMINED from performance_schema.events_statements_history order by TIMER_START desc limit 10 | 0.5577 | 2 | | truncate table performance_schema.events_statements_history | 0.9153 | 0 | +-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+---------------+ 7 rows in set (0.00 sec) root@localhost [sys]>
【参考】
■ この動画とPDFは参考になる良い資料です。
https://community.oracle.com/docs/DOC-997564
■ こちらのツールを利用すると複数MySQLのシステムとSQLを監視する事が出来ます。
簡単にGUIベースで確認して管理コスト削減したいたい場合はお勧めします。
https://www-jp.mysql.com/products/enterprise/monitor.html
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