[英]mysql query running very slow. Please help me with indexes
I'm trying to run a query which is taking 5 seconds to execute with 100000 rows. 我正在尝试运行一个查询,该查询需要5秒钟来执行100000行。 The query is given below.
查询如下。 I've tried all possible indexes i could.
我已经尝试了所有可能的索引。 Please suggest me what am i missing.
请建议我我想念的是什么。
select distinct db_books.bookid as id
, request_type.name as book_type
, request_type.id as book_type_id
, db_books.subject as subject
, sender_user.uid as sender_user_id
, sender_user.username as sender_user
, sender_company.companyid as sender_company_id
, sender_company.companyname as sender_company
, sender_team_id.teamid as sender_team_id
, sender_team_id.name as sender_team
, GROUP_CONCAT(distinct receiver_user_details.uid separator '|') as receiver_user_id
, GROUP_CONCAT(distinct receiver_user_details.username separator '|') as receiver_user
, GROUP_CONCAT(distinct receiver_company.companyid separator '|') as receiver_company_id
, GROUP_CONCAT(distinct receiver_company.companyname separator '|') as receiver_company
, GROUP_CONCAT(distinct receiver_team_details.teamid separator '|') as receiver_team_id
, GROUP_CONCAT(distinct receiver_team_details.name separator '|') as receiver_team
, status.id as statusid
, status.name as status
, db_books.modifydate as modified_date
, db_books.createddate as creation_date
, state.id as stateid
, state.name as state
, assignee.uid as assignee_user_id
, assignee.username as assignee_user
, purpose.name as purpose
, purpose.id as purposeid
, g.name as entityname
, g.entityid as entityid
from db_books db_books
inner join db_users sender_user on (sender_user.deleted=0 and sender_user.uid=db_books.sndrUserid)
inner join db_companies sender_company on (sender_company.deleted=0 and sender_company.companyid=db_books.sndrCompanyid)
inner join db_companies receiver_company on (receiver_company.deleted=0 and receiver_company.companyid=db_books.target_company_id)
inner join db_request_types request_type on (request_type.id=db_books.book_type_id)
left outer join db_teams sender_team_id on (sender_team_id.deleted=0 and sender_team_id.teamid=db_books.sender_team_id)
left outer join db_books_to_users receiver_user on (receiver_user.bookid=db_books.bookid)
left outer join db_users receiver_user_details on (receiver_user_details.uid=receiver_user.userid)
left outer join db_books_to_teams receiver_teams on (receiver_teams.bookid=db_books.bookid)
left outer join db_teams receiver_team_details on (receiver_team_details.teamid=receiver_teams.teamid)
left outer join db_request_status status on (status.id=db_books.statusid)
left outer join db_request_state_types state on (state.id=db_books.request_state_id)
left outer join db_request_purpose purpose on (purpose.id=db_books.request_purpose_id)
left outer join db_users assignee on (assignee.uid=db_books.assignee)
left outer join db_books_details mdtl on (mdtl.deleted=0 and mdtl.bookid=db_books.bookid)
left outer join db_entities g on (g.deleted=0 and g.entityid=mdtl.entityid)
where 1=1
and
(db_books.sndrUserid=25000000003265
or db_books.sender_team_id in (
select a.teamid from db_team_users a
inner join db_teams b on (b.teamid=a.teamid and b.deleted=0)
where a.userid=25000000003265
)
or db_books.bookid in (
select distinct bookid from db_books_to_users where userid=25000000003265
union
select distinct bookid from db_books_to_teams where teamid in
(
select a.teamid from db_team_users a
inner join db_teams b on (b.teamid=a.teamid and b.deleted=0)
where a.deleted=0 AND a.userid=25000000003265
)
)
)
group by db_books.bookid
limit 20
The explain plan is as given below. 解释计划如下。
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY sender_user ALL PRIMARY,u2 14573 Using where; Using temporary; Using filesort
1 PRIMARY db_books ref i_db_books_target_company_id,i_db_books_sndrUserid,i_db_books_sndrCompanyid,i_sndrUserid_sender_team_idbookid i_db_books_sndrUserid 7 mde_staging.sender_user.uid 41 Using where
1 PRIMARY sender_company eq_ref PRIMARY,db_companies_icd PRIMARY 7 mde_staging.db_books.sndrCompanyid 1 Using where
1 PRIMARY receiver_company eq_ref PRIMARY,db_companies_icd PRIMARY 7 mde_staging.db_books.target_company_id 1 Using where
1 PRIMARY sender_team_id eq_ref PRIMARY,db_teams_i PRIMARY 7 mde_staging.db_books.sender_team_id 1
1 PRIMARY receiver_user ref i_db_books_to_users_bookid i_db_books_to_users_bookid 7 mde_staging.db_books.bookid 1
1 PRIMARY receiver_user_details eq_ref PRIMARY,u2 PRIMARY 7 mde_staging.receiver_user.userid 1
1 PRIMARY receiver_teams ref i_db_books_to_teams_bookid i_db_books_to_teams_bookid 7 mde_staging.db_books.bookid 1
1 PRIMARY receiver_team_details eq_ref PRIMARY,db_teams_i PRIMARY 7 mde_staging.receiver_teams.teamid 1
1 PRIMARY status eq_ref PRIMARY PRIMARY 4 mde_staging.db_books.statusid 1
1 PRIMARY state eq_ref PRIMARY PRIMARY 4 mde_staging.db_books.request_state_id 1
1 PRIMARY purpose eq_ref PRIMARY PRIMARY 4 mde_staging.db_books.request_purpose_id 1
1 PRIMARY assignee eq_ref PRIMARY,u2 PRIMARY 7 mde_staging.db_books.assignee 1
1 PRIMARY mdtl ref db_books_details_bookid db_books_details_bookid 7 mde_staging.db_books.bookid 1
1 PRIMARY request_type ALL PRIMARY 4 Using where; Using join buffer
1 PRIMARY g eq_ref PRIMARY,db_entities7 PRIMARY 7 mde_staging.mdtl.entityid 1
3 DEPENDENT SUBQUERY db_books_to_users ref i_db_books_to_users_bookid i_db_books_to_users_bookid 7 func 1 Using where; Using temporary
4 DEPENDENT UNION db_books_to_teams ref i_db_books_to_teams_bookid i_db_books_to_teams_bookid 7 func 1 Using where; Using temporary
5 DEPENDENT SUBQUERY b eq_ref PRIMARY,db_teams_i PRIMARY 7 func 1 Using where
5 DEPENDENT SUBQUERY a ref db_team_users_i db_team_users_i 11 func,const 1 Using where
UNION RESULT <union3,4> ALL
2 DEPENDENT SUBQUERY b eq_ref PRIMARY,db_teams_i PRIMARY 7 func 1 Using where
2 DEPENDENT SUBQUERY a ref db_team_users_i db_team_users_i 7 func 1 Using where
If you see the first row of the explain plan, it is not using the possible index and then using file sort etc. Not sure if that is the problem. 如果您看到解释计划的第一行,则它没有使用可能的索引,然后使用文件排序等。不确定是否是问题所在。 Please suggest me how to fix this or me what indexes to use??
请建议我如何解决这个问题或我要使用什么索引?
The biggest problem I see is the subquery qualifiers. 我看到的最大问题是子查询限定符。 Those hit per every row tested.
每一行测试的点击率。 I would then change the WHERE clause portion to just a prequery as the first table and get those resulting books and join to books, then the rest should be fine.
然后,我将WHERE子句部分更改为仅作为第一个表的预查询,并获得这些结果书并加入书中,其余的应该没问题。 In addition, the clause "STRAIGHT_JOIN" tells the engine to do the query in the order you've said.
另外,子句“ STRAIGHT_JOIN”告诉引擎按照您说的顺序进行查询。 Sometimes, it gets to ahead of you and tries to optimize based on one of the "lookup" reference tables and back-fill find the rest.
有时,它会领先于您,并尝试根据“查找”参考表之一进行优化,然后回填以查找其余部分。 All that said,
这么说
CHANGE the SELECT at the top to 将顶部的选择更改为
select STRAIGHT_JOIN distinct
and then your from clause from 然后您的from子句来自
from
db_books db_books
to 至
from
( SELECT distinct db.bookid
from
db_books db
left join db_team_users TeamA
ON db.sndrUserID = TeamA.userID
AND db.Sender_Team_ID = TeamA.TeamID
LEFT JOIN db_teams TeamB
ON TeamA.TeamID = TeamB.TeamID
AND TeamB.Deleted = 0
left join db_books_to_users ToUser
ON db.BookID = ToUser.BookID
AND db.sndrUserID = ToUser.userID
left join db_books_to_teams ToTeamA
ON db.TeamID = ToTeamA.TeamID
AND db.sndrUserID = ToTeamA.UserID
AND a.Deleted = 0
left join db_teams ToTeamsB
ON ToTeamA.TeamID = ToTeamB.TeamID
AND b.Deleted = 0
where
db.sndrUserID = 25000000003265
OR NOT TeamB.TeamID IS NULL
OR NOT ToUser.BookID IS NULL
OR NOT ToTeamB.TeamID IS NULL
limit
20 ) PreQualBooks
JOIN db_books
ON PreQualBooks.BookID = db_Books.BookID
And you can remove the Final WHERE clause as this prequery will be done ONCE up front to pre-qualify every POSSIBLE book ID based on user or team relationship with JOINs. 而且,您可以删除Final WHERE子句,因为该预查询将一次完成,从而可以根据用户或团队与JOIN的关系对每个可能的书ID进行预认证。 By allowing LEFT JOIN, the books table goes through ONCE, with all the respective relationships to team / user status and will only return those records based on the send user OR the lowest level of the respective LEFT JOINs (TeamB, ToUser and ToTeamB).
通过允许LEFT JOIN,books表通过ONCE,并具有与团队/用户状态的所有各个关系,并且仅基于发送用户或各个LEFT JOIN的最低级别(TeamB,ToUser和ToTeamB)返回那些记录。 This prequery also applies the limit to 20 books, so the LIMIT clause at the end of your query is not needed either as only 20 books will ever be POSSIBLE.
此预查询还将限制应用于20本书,因此也不需要查询末尾的LIMIT子句,因为只有20本书才是可能的。
Leave your Outer GROUP BY due to your group_concat. 由于您的group_concat,请离开您的外部GROUP BY。
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