MySQL解释基于条件值的计划更改_Mysql

MySQL解释基于条件值的计划更改

mysql

MySQL解释基于条件值的计划更改,mysql,Mysql,今天，我们注意到两个显然相同的查询导致了截然不同的执行计划，从而导致了截然不同的性能。另一个令人吃惊的事实是，聚合超过50k+行的查询比聚合超过600个结果的查询运行速度快30倍。 “快速”查询运行约400ms，“慢速”查询运行约10sc 慢速查询： SELECT account_ownership_id, count(*) FROM posts JOIN accounts ON posts.account_id = accounts.id JOIN platforms ON accounts

今天，我们注意到两个显然相同的查询导致了截然不同的执行计划，从而导致了截然不同的性能。另一个令人吃惊的事实是，聚合超过50k+行的查询比聚合超过600个结果的查询运行速度快30倍。 “快速”查询运行约400ms，“慢速”查询运行约10sc

慢速查询：

SELECT account_ownership_id, count(*)
FROM posts
JOIN accounts ON posts.account_id = accounts.id
JOIN platforms ON accounts.platform_id = platforms.id 
JOIN sponsor_annotations ON sponsor_annotations.post_id = posts.id
JOIN rightsholders_placements
ON (rightsholders_placements.rightsholder_id = sponsor_annotations.rightsholder_id
AND rightsholders_placements.placement_id = sponsor_annotations.placement_id)
JOIN clients_sponsors_placements
ON (clients_sponsors_placements.rightsholder_id = sponsor_annotations.rightsholder_id
AND clients_sponsors_placements.sponsor_id = sponsor_annotations.sponsor_id
AND clients_sponsors_placements.placement_id = sponsor_annotations.placement_id)
WHERE  clients_sponsors_placements.client_id = 1125   and accounts.platform_id = 5 
GROUP BY sponsor_annotations.account_ownership_id LIMIT 1000

+---+--------+-----------------------------+--------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------+----+--------------------------------------------------------------------------------------------------------------------------------+-----+-------+----------------------------------------------+
| 1 | SIMPLE | platforms                   | const  | PRIMARY                                                                                                                                                                                     | PRIMARY               | 4  | const                                                                                                                          | 1   | 100.0 | Using index; Using temporary; Using filesort |
| 1 | SIMPLE | accounts                    | ref    | PRIMARY,fk_accounts_platforms                                                                                                                                                               | fk_accounts_platforms | 4  | const                                                                                                                          | 354 | 100.0 | Using index                                  |
| 1 | SIMPLE | posts                       | ref    | PRIMARY,fk_posts_accounts_id                                                                                                                                                                | fk_posts_accounts_id  | 4  | sports.accounts.id                                                                                                             | 2   | 100.0 | Using index                                  |
| 1 | SIMPLE | sponsor_annotations         | ref    | sponsor_annotations,fk_sponsor_annotations_sponsor_placements,fk_sponsor_annotations_rightsholder_placements,fk_sponsor_annotations_sponsors,fk_sponsor_annotations_account_ownership_types | sponsor_annotations   | 4  | sports.posts.id                                                                                                                | 29  | 100.0 |                                              |
| 1 | SIMPLE | clients_sponsors_placements | eq_ref | PRIMARY,fk_client_sponsor_placements_clients_rightsholders_sponsors,fk_client_sponsor_placements_sponsor_placements                                                                         | PRIMARY               | 16 | const,sports.sponsor_annotations.placement_id,sports.sponsor_annotations.rightsholder_id,sports.sponsor_annotations.sponsor_id | 1   | 100.0 | Using index                                  |
| 1 | SIMPLE | rightsholders_placements    | eq_ref | PRIMARY,fk_rightsholders_placements_rightsholders                                                                                                                                           | PRIMARY               | 8  | sports.sponsor_annotations.placement_id,sports.sponsor_annotations.rightsholder_id                                             | 1   | 100.0 | Using index                                  |
+---+--------+-----------------------------+--------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------+----+--------------------------------------------------------------------------------------------------------------------------------+-----+-------+----------------------------------------------+

快速查询：

SELECT account_ownership_id, count(*)
FROM posts
JOIN accounts ON posts.account_id = accounts.id
JOIN platforms ON accounts.platform_id = platforms.id 
JOIN sponsor_annotations ON sponsor_annotations.post_id = posts.id
JOIN rightsholders_placements
ON (rightsholders_placements.rightsholder_id = sponsor_annotations.rightsholder_id
AND rightsholders_placements.placement_id = sponsor_annotations.placement_id)
JOIN clients_sponsors_placements
ON (clients_sponsors_placements.rightsholder_id = sponsor_annotations.rightsholder_id
AND clients_sponsors_placements.sponsor_id = sponsor_annotations.sponsor_id
AND clients_sponsors_placements.placement_id = sponsor_annotations.placement_id)
WHERE  clients_sponsors_placements.client_id = 1125   and accounts.platform_id = 1
GROUP BY sponsor_annotations.account_ownership_id LIMIT 1000

如您所见，这两个查询之间的唯一区别在于平台id where子句。我希望查询计划非常相似，但事实并非如此。而且，即使缓慢的查询聚集在更少的行上，也要花费更多的时间

同样有趣的是，将条件更改为“accounts.platform_id in（1,5）”可以显著加快查询速度（查询速度与我们执行accounts.platform_id=1的查询速度一样快）

以下是慢速查询的解释计划：

SELECT account_ownership_id, count(*)
FROM posts
JOIN accounts ON posts.account_id = accounts.id
JOIN platforms ON accounts.platform_id = platforms.id 
JOIN sponsor_annotations ON sponsor_annotations.post_id = posts.id
JOIN rightsholders_placements
ON (rightsholders_placements.rightsholder_id = sponsor_annotations.rightsholder_id
AND rightsholders_placements.placement_id = sponsor_annotations.placement_id)
JOIN clients_sponsors_placements
ON (clients_sponsors_placements.rightsholder_id = sponsor_annotations.rightsholder_id
AND clients_sponsors_placements.sponsor_id = sponsor_annotations.sponsor_id
AND clients_sponsors_placements.placement_id = sponsor_annotations.placement_id)
WHERE  clients_sponsors_placements.client_id = 1125   and accounts.platform_id = 5 
GROUP BY sponsor_annotations.account_ownership_id LIMIT 1000

+---+--------+-----------------------------+--------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------+----+--------------------------------------------------------------------------------------------------------------------------------+-----+-------+----------------------------------------------+
| 1 | SIMPLE | platforms                   | const  | PRIMARY                                                                                                                                                                                     | PRIMARY               | 4  | const                                                                                                                          | 1   | 100.0 | Using index; Using temporary; Using filesort |
| 1 | SIMPLE | accounts                    | ref    | PRIMARY,fk_accounts_platforms                                                                                                                                                               | fk_accounts_platforms | 4  | const                                                                                                                          | 354 | 100.0 | Using index                                  |
| 1 | SIMPLE | posts                       | ref    | PRIMARY,fk_posts_accounts_id                                                                                                                                                                | fk_posts_accounts_id  | 4  | sports.accounts.id                                                                                                             | 2   | 100.0 | Using index                                  |
| 1 | SIMPLE | sponsor_annotations         | ref    | sponsor_annotations,fk_sponsor_annotations_sponsor_placements,fk_sponsor_annotations_rightsholder_placements,fk_sponsor_annotations_sponsors,fk_sponsor_annotations_account_ownership_types | sponsor_annotations   | 4  | sports.posts.id                                                                                                                | 29  | 100.0 |                                              |
| 1 | SIMPLE | clients_sponsors_placements | eq_ref | PRIMARY,fk_client_sponsor_placements_clients_rightsholders_sponsors,fk_client_sponsor_placements_sponsor_placements                                                                         | PRIMARY               | 16 | const,sports.sponsor_annotations.placement_id,sports.sponsor_annotations.rightsholder_id,sports.sponsor_annotations.sponsor_id | 1   | 100.0 | Using index                                  |
| 1 | SIMPLE | rightsholders_placements    | eq_ref | PRIMARY,fk_rightsholders_placements_rightsholders                                                                                                                                           | PRIMARY               | 8  | sports.sponsor_annotations.placement_id,sports.sponsor_annotations.rightsholder_id                                             | 1   | 100.0 | Using index                                  |
+---+--------+-----------------------------+--------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------+----+--------------------------------------------------------------------------------------------------------------------------------+-----+-------+----------------------------------------------+

以及更快查询的解释计划：

+---+--------+-----------------------------+--------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------------------+----+--------------------------------------------------------------------------------------------------------------------------------------------------+-----+-------+----------------------------------------------+
| 1 | SIMPLE | platforms                   | const  | PRIMARY                                                                                                                                                                                     | PRIMARY                                   | 4  | const                                                                                                                                            | 1   | 100.0 | Using index; Using temporary; Using filesort |
| 1 | SIMPLE | clients_sponsors_placements | ref    | PRIMARY,fk_client_sponsor_placements_clients_rightsholders_sponsors,fk_client_sponsor_placements_sponsor_placements                                                                         | PRIMARY                                   | 4  | const                                                                                                                                            | 223 | 100.0 | Using index                                  |
| 1 | SIMPLE | rightsholders_placements    | eq_ref | PRIMARY,fk_rightsholders_placements_rightsholders                                                                                                                                           | PRIMARY                                   | 8  | sports.clients_sponsors_placements.placement_id,sports.clients_sponsors_placements.rightsholder_id                                               | 1   | 100.0 | Using index                                  |
| 1 | SIMPLE | sponsor_annotations         | ref    | sponsor_annotations,fk_sponsor_annotations_sponsor_placements,fk_sponsor_annotations_rightsholder_placements,fk_sponsor_annotations_sponsors,fk_sponsor_annotations_account_ownership_types | fk_sponsor_annotations_sponsor_placements | 12 | sports.clients_sponsors_placements.rightsholder_id,sports.clients_sponsors_placements.sponsor_id,sports.clients_sponsors_placements.placement_id | 158 | 100.0 |                                              |
| 1 | SIMPLE | posts                       | eq_ref | PRIMARY,fk_posts_accounts_id                                                                                                                                                                | PRIMARY                                   | 4  | sports.sponsor_annotations.post_id                                                                                                               | 1   | 100.0 |                                              |
| 1 | SIMPLE | accounts                    | eq_ref | PRIMARY,fk_accounts_platforms                                                                                                                                                               | PRIMARY                                   | 4  | sports.posts.account_id                                                                                                                          | 1   | 100.0 | Using where                                  |
+---+--------+-----------------------------+--------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------------------------------------+----+--------------------------------------------------------------------------------------------------------------------------------------------------+-----+-------+----------------------------------------------+

如何更改查询或模式以确保在这两种情况下执行计划相同

谢谢，

可能会运行？如果取消

限制，您的快速查询是否会更快？根据有限的查询判断执行计划可能会产生误导。另外，您能否添加绝对执行时间（例如，它更像是1s对30s还是1ms对30ms？@Solarflare：我尝试取消限制，但没有改变执行时间。绝对执行时间为400ms vs 10秒。将其添加到我的原始消息中。@GhostGambler我对该查询涉及的所有表运行了ANALYZE TABLE，但它没有帮助。可能运行？如果删除限制，您的快速查询是否会更快？根据有限的查询判断执行计划可能会产生误导。另外，您能否添加绝对执行时间（例如，它更像是1s对30s还是1ms对30ms？@Solarflare：我尝试取消限制，但没有改变执行时间。绝对执行时间为400ms vs 10秒。将其添加到我的原始消息中。@GhostGambler我在该查询涉及的所有表上运行了ANALYZE TABLE，但没有任何帮助。