【发布时间】：2018-05-12 09:40:25
【问题描述】：
我正在将数据库从 mysql 迁移到 mariadb。 ruby on rails 应用程序正在使用 cancan 执行以下查询，因此我无法更改查询：
SELECT DISTINCT COUNT(DISTINCT `buildings`.`id`)
FROM `buildings`
INNER JOIN `structure_subtypes`
ON `structure_subtypes`.`id` = `buildings`.`structure_subtype_id`
WHERE `buildings`.`id` IN (33553, 33554, 33555, 33556, 33557,
33558, 33559, 33560, 33561, 33562, 33563, 33564, 33565,
33566, 33567, 33568, 33569, 33570, 33571, 33572, 33573,
33574, 33575, 33576,+ ,..., 439515, 439521, 439600, 439602,
439604, 440016, 440017, 440019, 440275, 440315, 440379,
440403, 440405, 412987, 439889, 439969, 439980, 440216,
440218, 440341, 440485, 440486, 440488, 440491, 440494,
440501, 441458, 441498, 441519, 441536, 443387, 443389,
443464, 433752, 440109, 440110, 440464, 443938, 440513,
440514, 443391, 443394, 443353, 443364, 443401, 443486,
175036, 175037
)
AND `buildings`.`client_id` IN (175, 47 , 162, 152, 170,
104, 90, 127, 101, 51, 163, 81, 164, 165, 166, 172, 137,
174, 106, 108, 161, 158, 169, 97, 123, 136, 102, 157,
167, 135, 105, 171, 180, 120, 119, 118, 121, 110, 59,
57, 178, 140, 138, 176, 141, 168, 126, 96, 117, 103, 133,
173, 131, 179, 80, 100, 95, 116, 142, 147, 159, 160, 154,
115, 153, 156, 91, 125, 144, 150, 93, 155, 149, 151, 146
)
AND `structure_subtypes`.`structure_type_id` IN (11, 12,
13, 14, 15
)
AND (buildings.created_at >= '2016-12-31 23:00:00')
AND (buildings.created_at <= '2017-12-31 22:59:59');
问题似乎是IN部分中的项目太多
MySQL "IN" operator performance on (large?) number of values
但问题在于 MYSQL 和 mariadb 之间的性能差异
对于 MYSQL，只需不到 10 秒
$ mysql -h 127.0.0.1 -u root -pPASSWORD database
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.6.35 MySQL Community Server (GPL)
Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MySQL [database]> RESET QUERY CACHE;
Query OK, 0 rows affected (0.00 sec)
MySQL [database]> Bye
$ mysql -h 127.0.0.1 -u root -pPASSWORD database < select_query.sql
RESULTS
ouput explain:
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE buildings range PRIMARY,fk__buildings_client_id,index_buildings_on_workflow_state,fk__buildings_structure_subtype_id,index_buildings_on_workflow_state_and_created_at,index_buildings_on_client_id_and_created_at
index_buildings_on_workflow_state_and_created_at 258 NULL 1001 Using index condition; Using where; Using temporary; Using filesort
1 SIMPLE structure_subtypes eq_ref PRIMARY,index_structure_subtypes_on_structure_type_code,fk__structure_subtypes_structure_type_id PRIMARY 4 antifraud.buildings.structure_subtype_id 1 Using where; Distinct
输出描述表
MySQL [antifraud]> describe buildings;
+--------------------------+---------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------------------+---------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| client_id | int(11) | YES | MUL | NULL | |
| observations | varchar(2000) | YES | | NULL | |
| created_at | datetime | NO | MUL | NULL | |
| updated_at | datetime | NO | | NULL | |
| workflow_state | varchar(255) | YES | MUL | NULL | |
| structure_subtype_id | int(11) | YES | MUL | NULL | |
| svs | tinyint(1) | YES | | NULL | |
| parent_id | int(11) | YES | MUL | NULL | |
| reference | varchar(255) | YES | | NULL | |
| soc_notify | tinyint(1) | YES | | NULL | |
| origin | int(11) | YES | | NULL | |
| category | int(11) | YES | | NULL | |
| ip_filtering | int(11) | YES | | NULL | |
| priority | int(11) | YES | | NULL | |
| creator_id | int(11) | YES | MUL | NULL | |
| external_id | varchar(255) | YES | | NULL | |
| duration_time | float | YES | | NULL | |
| reopening_at | datetime | YES | MUL | NULL | |
| closed_at | datetime | YES | | NULL | |
| cbs_detection_id_legacy | varchar(255) | YES | | NULL | |
| cbs_callback_legacy | varchar(255) | YES | | NULL | |
| load_percentage | float | YES | | NULL | |
| items_in_special_domains | tinyint(1) | NO | | 0 | |
+--------------------------+---------------+------+-----+---------+----------------+
24 rows in set (0.00 sec)
..
MySQL [antifraud]> show index from buildings;
+-----------+------------+--------------------------------------------------+--------------+-------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-----------+------------+--------------------------------------------------+--------------+-------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| buildings | 0 | PRIMARY | 1 | id | A | 72567 | NULL | NULL | | BTREE | | |
| buildings | 1 | fk__buildings_client_id | 1 | client_id | A | 82 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | index_buildings_on_workflow_state | 1 | workflow_state | A | 8 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | fk__buildings_structure_subtype_id | 1 | structure_subtype_id | A | 78 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | fk__buildings_parent_id | 1 | parent_id | A | 4535 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | fk__buildings_creator_id | 1 | creator_id | A | 168 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | index_buildings_on_workflow_state_and_created_at | 1 | workflow_state | A | 8 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | index_buildings_on_workflow_state_and_created_at | 2 | created_at | A | 72567 | NULL | NULL | | BTREE | | |
| buildings | 1 | index_buildings_on_created_at | 1 | created_at | A | 72567 | NULL | NULL | | BTREE | | |
| buildings | 1 | index_buildings_on_reopening_at | 1 | reopening_at | A | 806 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | index_buildings_on_client_id_and_created_at | 1 | client_id | A | 80 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | index_buildings_on_client_id_and_created_at | 2 | created_at | A | 72567 | NULL | NULL | | BTREE | | |
+-----------+------------+--------------------------------------------------+--------------+-------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
12 rows in set (0.00 sec)
MySQL [antifraud]> Bye
对于 MariaDB，需要 1 分 10 秒
$ mysql -h 127.0.0.1 -u root -pPASSWORD database
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 4
Server version: 10.1.26-MariaDB-1~jessie mariadb.org binary distribution
Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [database]> RESET QUERY CACHE;
Query OK, 0 rows affected (0.00 sec)
MariaDB [database]> Bye
$ mysql -h 127.0.0.1 -u root -pPASSWORD database < select_query.sql
ouput explain:
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE buildings range PRIMARY,fk__buildings_client_id,index_buildings_on_workflow_state,fk__buildings_structure_subtype_id,index_buildings_on_workflow_state_and_created_at,index_buildings_on_client_id_and_created_at index_buildings_on_workflow_state_and_created_at 258 NULL 1001 Using index condition; Using where; Using temporary; Using filesort
1 SIMPLE structure_subtypes eq_ref PRIMARY,index_structure_subtypes_on_structure_type_code,fk__structure_subtypes_structure_type_id PRIMARY 4 antifraud.buildings.structure_subtype_id 1 Using where; Distinct
..
output describe table
MariaDB [antifraud]> describe buildings;
+--------------------------+---------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------------------+---------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| client_id | int(11) | YES | MUL | NULL | |
| observations | varchar(2000) | YES | | NULL | |
| created_at | datetime | NO | MUL | NULL | |
| updated_at | datetime | NO | | NULL | |
| workflow_state | varchar(255) | YES | MUL | NULL | |
| structure_subtype_id | int(11) | YES | MUL | NULL | |
| svs | tinyint(1) | YES | | NULL | |
| parent_id | int(11) | YES | MUL | NULL | |
| reference | varchar(255) | YES | | NULL | |
| soc_notify | tinyint(1) | YES | | NULL | |
| origin | int(11) | YES | | NULL | |
| category | int(11) | YES | | NULL | |
| ip_filtering | int(11) | YES | | NULL | |
| priority | int(11) | YES | | NULL | |
| creator_id | int(11) | YES | MUL | NULL | |
| external_id | varchar(255) | YES | | NULL | |
| duration_time | float | YES | | NULL | |
| reopening_at | datetime | YES | MUL | NULL | |
| closed_at | datetime | YES | | NULL | |
| cbs_detection_id_legacy | varchar(255) | YES | | NULL | |
| cbs_callback_legacy | varchar(255) | YES | | NULL | |
| load_percentage | float | YES | | NULL | |
| items_in_special_domains | tinyint(1) | NO | | 0 | |
+--------------------------+---------------+------+-----+---------+----------------+
24 rows in set (0.00 sec)
MariaDB [antifraud]> show index from buildings;
+-----------+------------+--------------------------------------------------+--------------+-------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-----------+------------+--------------------------------------------------+--------------+-------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| buildings | 0 | PRIMARY | 1 | id | A | 71923 | NULL | NULL | | BTREE | | |
| buildings | 1 | fk__buildings_client_id | 1 | client_id | A | 82 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | index_buildings_on_workflow_state | 1 | workflow_state | A | 8 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | fk__buildings_structure_subtype_id | 1 | structure_subtype_id | A | 80 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | fk__buildings_parent_id | 1 | parent_id | A | 4495 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | fk__buildings_creator_id | 1 | creator_id | A | 170 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | index_buildings_on_workflow_state_and_created_at | 1 | workflow_state | A | 8 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | index_buildings_on_workflow_state_and_created_at | 2 | created_at | A | 71923 | NULL | NULL | | BTREE | | |
| buildings | 1 | index_buildings_on_created_at | 1 | created_at | A | 71923 | NULL | NULL | | BTREE | | |
| buildings | 1 | index_buildings_on_reopening_at | 1 | reopening_at | A | 826 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | index_buildings_on_client_id_and_created_at | 1 | client_id | A | 80 | NULL | NULL | YES | BTREE | | |
| buildings | 1 | index_buildings_on_client_id_and_created_at | 2 | created_at | A | 71923 | NULL | NULL | | BTREE | | |
+-----------+------------+--------------------------------------------------+--------------+-------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
12 rows in set (0.00 sec)
我正在使用显示变量中的变量，但我不知道如何进行
【问题讨论】：
-
在 MySQL 和 mariadb 上显示来自
explain select ...的输出，以及每个表的show create table tablename的输出（以及 MySQL 和 Maria 之间后者的任何差异） -
添加了解释和描述
-
Describe 不会像
show create table ... \G那样显示索引详细信息。更新：我看到你确实显示了索引，谢谢。不过，这更难阅读 -
@anquegi - DESCRIBE 和 SHOW INDEX 输出有什么不同吗？
-
请提供
SHOW CREATE TABLE structure_subtypes