MySQL 8.0 Группировка по производительности - PullRequest
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MySQL 8.0 Группировка по производительности

0 голосов
/ 24 мая 2018

Для сравнения MySQL 5.7 и 8.0 я создал таблицу с помощью sysbench.И я попробовал тест.Производительность сервера точно такая же. В результате oltp_point_select показал почти одинаковую производительность.

Однако при выполнении группы с помощью тестов, приведенных ниже, MySQL 8.0 показал в 10 раз лучшую производительность.Но я не знаю, почему это быстро.

Я не знаю, смогу ли я найти заметки о выпуске MySQL 8.0.В 8.0, кто скажет мне, почему группировка по быстрее?

0.схема таблицы 

CREATE TABLE `sbtest2` (

  `id` int(11) NOT NULL AUTO_INCREMENT,
  `k` int(11) NOT NULL DEFAULT '0',
  `c` char(120) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
  `pad` char(60) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
  PRIMARY KEY (`id`),
  KEY `k_2` (`k`),
  KEY `idx1` (`k`,`pad`)
) ENGINE=InnoDB AUTO_INCREMENT=1099289 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci

1.MySQL 5.7 Версия сервера: 5.7.17-log Исходный текст

5.7 РЕЗУЛЬТАТ 

    testdb 17:24:38 > select count(0),pad from sbtest2 where k between 400000 and 600000 group by pad limit 1;
        +----------+-------------------------------------------------------------+
        | count(0) | pad                                                         |
        +----------+-------------------------------------------------------------+
        |        1 | 00000012813-73478546096-60491222567-55128816668-26346684571 |
        +----------+-------------------------------------------------------------+
        **1 row in set (21.88 sec)**

testdb 17:21:30 > explain select count(0),pad from sbtest2 where k between 400000 and 600000 group by pad limit 10\G
    *************************** 1. row ***************************
               id: 1
      select_type: SIMPLE
            table: sbtest2
       partitions: NULL
             type: range
    possible_keys: k_2,idx1
              key: idx1
          key_len: 4
              ref: NULL
             rows: 493200
         filtered: 100.00
            Extra: Using where; Using index; Using temporary; Using filesort
    1 row in set, 1 warning (0.00 sec)


    17:55:17 > show profile;
        +---------------------------+-----------+
        | Status                    | Duration  |
        +---------------------------+-----------+
        | starting                  |  0.000083 |
        | checking permissions      |  0.000008 |
        | Opening tables            |  0.000017 |
        | init                      |  0.000032 |
        | System lock               |  0.000013 |
        | optimizing                |  0.000010 |
        | statistics                |  0.076138 |
        | preparing                 |  0.000018 |
        | Creating tmp table        |  0.000033 |
        | Sorting result            |  0.000005 |
        | executing                 |  0.000003 |
        | Sending data              |  2.790353 |
        | converting HEAP to ondisk |  1.709809 |
        | Sending data              | 14.403732 |
        | Creating sort index       |  2.236432 |
        | end                       |  0.000014 |
        | query end                 |  0.000012 |
        | removing tmp table        |  0.017293 |
        | query end                 |  0.000007 |
        | closing tables            |  0.000011 |
        | freeing items             |  0.000252 |
        | logging slow query        |  0.000055 |
        | cleaning up               |  0.000014 |
        +---------------------------+-----------+

2.MySQL 8.0 Версия сервера: 8.0.11 MySQL Community Server - GPL

RESULT 

 testdb 17:24:24 > select count(0),pad from sbtest2 where k between 400000 and 600000 group by pad limit 1;
    +----------+-------------------------------------------------------------+
    | count(0) | pad                                                         |
    +----------+-------------------------------------------------------------+
    |        1 | 30506873183-39276415649-14634764539-17515472140-54546407224 |
    +----------+-------------------------------------------------------------+
    **1 row in set (2.32 sec)**

 testdb 17:23:29 > explain select count(0),pad from sbtest2 where k between 400000 and 600000 group by pad limit 10\G
    *************************** 1. row ***************************
               id: 1
      select_type: SIMPLE
            table: sbtest2
       partitions: NULL
             type: range
    possible_keys: k_2,idx1
              key: idx1
          key_len: 4
              ref: NULL
             rows: 493200
         filtered: 100.00
            Extra: Using where; Using index; Using temporary
    1 row in set, 1 warning (0.04 sec)


    testdb 17:55:00 > show profile;
    +----------------------+----------+
    | Status               | Duration |
    +----------------------+----------+
    | starting             | 0.000103 |
    | checking permissions | 0.000018 |
    | Opening tables       | 0.000051 |
    | init                 | 0.000008 |
    | System lock          | 0.000013 |
    | optimizing           | 0.000010 |
    | statistics           | 0.000144 |
    | preparing            | 0.000024 |
    | Creating tmp table   | 0.000042 |
    | executing            | 0.000004 |
    | Sending data         | 2.407031 |
    | end                  | 0.000018 |
    | query end            | 0.000019 |
    | removing tmp table   | 0.087750 |
    | query end            | 0.000020 |
    | closing tables       | 0.000018 |
    | freeing items        | 0.000193 |
    | logging slow query   | 0.000061 |
    | cleaning up          | 0.000015 |
    +----------------------+----------+

@ Рик Джеймс Таблица 5.7 sbtest2 была выгружена и применена к 8.0.Теперь две таблицы абсолютно одинаковы. 

5_7.testdb 18:25:13 > select @@version;
+------------+
| @@version  |
+------------+
| 5.7.17-log |
+------------+
1 row in set (0.00 sec)

5_7.testdb 18:25:16 > select count(*) from sbtest2;
+----------+
| count(*) |
+----------+
|  1099288 |
+----------+
1 row in set (0.17 sec)

5_7.testdb 18:25:22 > select count(0),pad from sbtest2 where k between 400000 and 500000 group by pad order by pad limit 1;
+----------+-------------------------------------------------------------+
| count(0) | pad                                                         |
+----------+-------------------------------------------------------------+
|        1 | 00000012813-73478546096-60491222567-55128816668-26346684571 |
+----------+-------------------------------------------------------------+
1 row in set (7.34 sec)

5_7.testdb 18:26:15 > explain select count(0),pad from sbtest2 where k between 400000 and 500000 group by pad order by pad limit 1;        
+----+-------------+---------+------------+-------+---------------+------+---------+------+--------+----------+-----------------------------------------------------------+
| id | select_type | table   | partitions | type  | possible_keys | key  | key_len | ref  | rows   | filtered | Extra                                                     |
+----+-------------+---------+------------+-------+---------------+------+---------+------+--------+----------+-----------------------------------------------------------+
|  1 | SIMPLE      | sbtest2 | NULL       | range | k_2,idx1      | idx1 | 4       | NULL | 542160 |   100.00 | Using where; Using index; Using temporary; Using filesort |
+----+-------------+---------+------------+-------+---------------+------+---------+------+--------+----------+-----------------------------------------------------------+
1 row in set, 1 warning (0.00 sec)

Note (Code 1003): /* select#1 */ select count(0) AS `count(0)`,`testdb`.`sbtest2`.`pad` AS `pad` from `testdb`.`sbtest2` where (`testdb`.`sbtest2`.`k` between 400000 and 500000) group by `testdb`.`sbtest2`.`pad` order by `testdb`.`sbtest2`.`pad` limit 1
5_7.testdb 18:26:27 > explain format=json select count(0),pad from sbtest2 where k between 400000 and 500000 group by pad order by pad limit 1;        
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| EXPLAIN                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| {
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "232810.86"
    },
    "ordering_operation": {
      "using_filesort": false,
      "grouping_operation": {
        "using_temporary_table": true,
        "using_filesort": true,
        "table": {
          "table_name": "sbtest2",
          "access_type": "range",
          "possible_keys": [
            "k_2",
            "idx1"
          ],
          "key": "idx1",
          "used_key_parts": [
            "k"
          ],
          "key_length": "4",
          "rows_examined_per_scan": 542160,
          "rows_produced_per_join": 542160,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "124378.86",
            "eval_cost": "108432.00",
            "prefix_cost": "232810.86",
            "data_read_per_join": "380M"
          },
          "used_columns": [
            "id",
            "k",
            "pad"
          ],
          "attached_condition": "(`testdb`.`sbtest2`.`k` between 400000 and 500000)"
        }
      }
    }
  }
} |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set, 1 warning (0.00 sec)

8.0 

8_0.testdb 18:25:00 >  select @@version;
+-----------+
| @@version |
+-----------+
| 8.0.11    |
+-----------+
1 row in set (0.00 sec)

8_0.testdb 18:25:25 > select count(*) from sbtest2;
+----------+
| count(*) |
+----------+
|  1099288 |
+----------+
1 row in set (0.16 sec)

8_0.testdb 18:25:29 > select count(0),pad from sbtest2 where k between 400000 and 500000 group by pad order by pad limit 1;
+----------+-------------------------------------------------------------+
| count(0) | pad                                                         |
+----------+-------------------------------------------------------------+
|        1 | 00000012813-73478546096-60491222567-55128816668-26346684571 |
+----------+-------------------------------------------------------------+
1 row in set (1.27 sec)

8_0.testdb 18:26:04 > explain select count(0),pad from sbtest2 where k between 400000 and 500000 group by pad order by pad limit 1;        
+----+-------------+---------+------------+-------+---------------+------+---------+------+--------+----------+-----------------------------------------------------------+
| id | select_type | table   | partitions | type  | possible_keys | key  | key_len | ref  | rows   | filtered | Extra                                                     |
+----+-------------+---------+------------+-------+---------------+------+---------+------+--------+----------+-----------------------------------------------------------+
|  1 | SIMPLE      | sbtest2 | NULL       | range | k_2,idx1      | idx1 | 4       | NULL | 503160 |   100.00 | Using where; Using index; Using temporary; Using filesort |
+----+-------------+---------+------------+-------+---------------+------+---------+------+--------+----------+-----------------------------------------------------------+
1 row in set, 1 warning (0.00 sec)

Note (Code 1003): /* select#1 */ select count(0) AS `count(0)`,`testdb`.`sbtest2`.`pad` AS `pad` from `testdb`.`sbtest2` where (`testdb`.`sbtest2`.`k` between 400000 and 500000) group by `testdb`.`sbtest2`.`pad` order by `testdb`.`sbtest2`.`pad` limit 1
8_0.testdb 18:26:23 > explain format=json select count(0),pad from sbtest2 where k between 400000 and 500000 group by pad order by pad limit 1;        
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| EXPLAIN                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| {
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "104331.96"
    },
    "ordering_operation": {
      "using_filesort": false,
      "grouping_operation": {
        "using_temporary_table": true,
        "using_filesort": true,
        "table": {
          "table_name": "sbtest2",
          "access_type": "range",
          "possible_keys": [
            "k_2",
            "idx1"
          ],
          "key": "idx1",
          "used_key_parts": [
            "k"
          ],
          "key_length": "4",
          "rows_examined_per_scan": 503160,
          "rows_produced_per_join": 503160,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "54015.96",
            "eval_cost": "50316.00",
            "prefix_cost": "104331.96",
            "data_read_per_join": "353M"
          },
          "used_columns": [
            "id",
            "k",
            "pad"
          ],
          "attached_condition": "(`testdb`.`sbtest2`.`k` between 400000 and 500000)"
        }
      }
    }
  }
} |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set, 1 warning (0.00 sec)

1 Ответ

0 голосов
/ 28 мая 2018

MySQL 8.0 использует новый механизм хранения TempTable для внутренних временных таблиц.(Подробнее см. Руководство по MySQL .) Этот механизм не имеет максимального ограничения памяти на таблицу, но имеет общий пул памяти для всех внутренних таблиц.Он также имеет собственный механизм переполнения на диск и не переполняется на InnoDB или MyISAM, как в более ранних версиях.

Профиль для 5.7 содержит «преобразование HEAP в ondisk».Это означает, что таблица достигла максимального размера таблицы для механизма MEMORY (по умолчанию 16 МБ) и данные передаются в InnoDB.Большую часть времени после этого тратится на доступ к временной таблице в InnoDB.В MySQL 8.0 размер пула памяти для временных таблиц по умолчанию составляет 1 ГБ, поэтому в этом случае, вероятно, переполнения диска не будет.

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