1.query is taking around 10mins to 1 hr to execute.
2.due to this we are getting load spikes frequently.
3.please help me to rewrite the query.
4.also help me to improve the performance of query.
Query with explain plan
explain select count(*)
from t_event eve
left join t_event_element_rel rel on rel.event_id = eve.id
left join t_object object on eve.create_object_id = object.id
left join t_keyword keyword on rel.element_id = keyword.id and rel.element_type_id = 1
left join t_target_url targeturl on rel.element_id = targeturl.id and rel.element_type_id = 2
where eve.domain_id = 522
+----+-------------+-----------+--------+-------------------------+-------------------------+---------+----------------------------+--------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-----------+--------+-------------------------+-------------------------+---------+----------------------------+--------+-------------+
| 1 | SIMPLE | eve | ref | domain_id_event_type_cd | domain_id_event_type_cd | 4 | const | 243430 | |
| 1 | SIMPLE | rel | ref | FK_event | FK_event | 4 | company.eve.id | 2 | |
| 1 | SIMPLE | user | eq_ref | PRIMARY | PRIMARY | 4 | company.eve.create_user_id | 1 | Using index |
| 1 | SIMPLE | keyword | ref | id | id | 4 | company.rel.element_id | 1 | Using index |
| 1 | SIMPLE | targeturl | ref | id | id | 4 | company.rel.element_id | 1 | Using index |
+----+-------------+-----------+--------+-------------------------+-------------------------+---------+----------------------------+--------+-------------+
5 rows in set (0.45 sec)
Table structure:
mysql> show create table t_event_element_rel\G
*************************** 1. row ***************************
Table: t_event_element_rel
Create Table: CREATE TABLE `t_event_element_rel` (
`id` int(255) NOT NULL AUTO_INCREMENT,
`element_type_id` int(11) NOT NULL,
`event_id` int(11) NOT NULL,
`element_id` int(11) NOT NULL,
`element_desc` varchar(500) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `FK_event` (`event_id`),
KEY `element_type_id_element_id` (`element_type_id`,`element_id`)
) ENGINE=InnoDB AUTO_INCREMENT=45901159 DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
mysql> show create table t_object\G
*************************** 1. row ***************************
Table: t_object
Create Table: CREATE TABLE `t_object` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`password` varchar(255) DEFAULT NULL,
`email` varchar(255) DEFAULT NULL,
`is_admin` int(11) DEFAULT NULL,
`phone` varchar(50) DEFAULT NULL,
`company` varchar(255) DEFAULT NULL,
`last_login` datetime DEFAULT NULL,
`state` int(11) DEFAULT NULL,
`validate_code` varchar(50) DEFAULT NULL,
`has_login` smallint(6) DEFAULT NULL COMMENT 'if null or 0 then hasn''t login, first time login',
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1304 DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
mysql> show create table t_event\G
*************************** 1. row ***************************
Table: t_event
Create Table: CREATE TABLE `t_event` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`create_user_id` int(11) DEFAULT NULL,
`event_create_date` date DEFAULT NULL,
`event_type_cd` int(11) NOT NULL,
`event_desc` varchar(512) NOT NULL,
`IsGlobalEvent` int(2) DEFAULT NULL,
`event_start_date` datetime NOT NULL,
`event_end_date` datetime NOT NULL,
`job_id` int(11) DEFAULT NULL,
`domain_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `event_user_FK` (`create_user_id`),
KEY `domain_id_event_type_cd` (`domain_id`,`event_type_cd`)
) ENGINE=InnoDB AUTO_INCREMENT=8586007 DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
mysql> show create table t_keyword\G
*************************** 1. row ***************************
Table: t_keyword
Create Table: CREATE TABLE `t_keyword` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`keyword_name` varchar(255) DEFAULT NULL,
`keyword_value` varchar(255) DEFAULT NULL,
`type` int(11) DEFAULT NULL,
`description` varchar(2000) DEFAULT NULL,
`own_domain_id` int(11) DEFAULT NULL,
`rank_check` int(11) DEFAULT NULL,
`rank1` int(11) DEFAULT NULL COMMENT 'yesterday rank value',
`rank2` int(11) DEFAULT NULL COMMENT 'the day before yesterday rank value',
`rank3` int(11) DEFAULT NULL COMMENT 'special date rank for overstock.com',
`yesterday_entrances` int(11) DEFAULT NULL COMMENT 'yesterday entrances',
`week_entrances` int(11) DEFAULT NULL COMMENT '7 days entrances',
`current_ctr` float(16,4) DEFAULT NULL COMMENT 'Current CTR',
`monthly_search_volume` int(11) DEFAULT NULL COMMENT 'Most Recent Month search volume',
`avg_monthly_search_volume` int(11) DEFAULT NULL COMMENT 'avg_monthly_search_volume',
`traffic_increase` int(11) DEFAULT NULL COMMENT 'Traffic Increase',
`rank_improvement` int(11) DEFAULT NULL COMMENT 'Rank Improvement',
`rank_update_date` date DEFAULT NULL COMMENT 'rank be updated for Special Date',
`top_rank_targeturl_id` int(11) DEFAULT NULL,
`frequency` int(10) DEFAULT '1' COMMENT '1: daily, 2: weekly, 3: monthly',
`score` float DEFAULT NULL,
`create_date` datetime DEFAULT NULL,
`bing_rank1` int(10) DEFAULT NULL,
`bing_rank2` int(10) DEFAULT NULL,
`yesterday_bing_entrances` int(11) DEFAULT NULL,
`bing_rank_improvement` int(11) DEFAULT NULL,
KEY `id` (`id`),
KEY `keyword_name` (`keyword_name`),
KEY `own_domain_id` (`own_domain_id`,`rank_check`),
KEY `rank_check` (`rank_check`)
) ENGINE=InnoDB AUTO_INCREMENT=670267018 DEFAULT CHARSET=utf8
/*!50100 PARTITION BY RANGE (`rank_check`)
(PARTITION p0 VALUES LESS THAN (0) ENGINE = InnoDB,
PARTITION p1 VALUES LESS THAN (1) ENGINE = InnoDB,
PARTITION p2 VALUES LESS THAN (2) ENGINE = InnoDB,
PARTITION pEOW VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */
1 row in set (0.00 sec)
mysql> show create table t_target_url\G
*************************** 1. row ***************************
Table: t_target_url
Create Table: CREATE TABLE `t_target_url` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`own_domain_id` int(11) DEFAULT NULL,
`url` varchar(2000) NOT NULL,
`create_date` datetime DEFAULT NULL,
`friendly_name` varchar(255) DEFAULT NULL,
`section_name_id` int(11) DEFAULT NULL,
`type` int(11) DEFAULT NULL,
`status` int(11) DEFAULT NULL,
`week_entrances` int(11) DEFAULT NULL COMMENT 'last 7 days entrances',
`week_bounces` int(11) DEFAULT NULL COMMENT 'last 7 days bounce',
`canonical_url_id` int(11) DEFAULT NULL COMMENT 'the primary URL ID, NOT allow canonical of canonical',
KEY `id` (`id`),
KEY `urlindex` (`url`(255)),
KEY `own_domain_id_type_status` (`own_domain_id`,`type`,`status`),
KEY `canonical_url_id` (`canonical_url_id`),
KEY `type` (`type`,`status`)
) ENGINE=InnoDB AUTO_INCREMENT=237034388 DEFAULT CHARSET=utf8
/*!50100 PARTITION BY RANGE (`type`)
(PARTITION p0 VALUES LESS THAN (0) ENGINE = InnoDB,
PARTITION p1 VALUES LESS THAN (1) ENGINE = InnoDB,
PARTITION p2 VALUES LESS THAN (2) ENGINE = InnoDB,
PARTITION pEOW VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */
1 row in set (0.01 sec)
The first line of your EXPLAIN shows a lot of rows for domain_id_event_type_cd, which is a compound index, yet in your query you only search on a part of the index (eve.domain_id = xxx). So unless domain 522 really has 243K entries, you can cut down on this by adding an index solely for domain_id.
Also, it seems you are trying to do an OR search by using rel.element_type_id as a "switch" for referencing different types of data. Since you are only interested in the count, I suggest you split the query in two parts, then add the results. This will cut down on the LEFT JOINS. You can even add the results within MySQL:
SELECT (SELECT COUNT (*) FROM ....) + (SELECT COUNT (*) FROM ...)
(You do know you can abuse SELECT to do math, don't you?)
Related
I have this query and takes 40 seconds, Is there a way to speed up? thank you
SELECT *, last.Date
FROM constant.derogation der
LEFT JOIN variable.last last
ON der.code = last.code
WHERE 1 = 1
AND status != 'removed'
ORDER BY status;
+------+-------------+-------+------+---------------+------+---------+------+--------+----------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+------+-------------+-------+------+---------------+------+---------+------+--------+----------------------------------------------+
| 1 | SIMPLE | der | ALL | NULL | NULL | NULL | NULL | 318 | Using where; Using temporary; Using filesort |
| 1 | SIMPLE | last | ALL | NULL | NULL | NULL | NULL | 250950 | Using where |
+------+-------------+-------+------+---------------+------+---------+------+--------+----------------------------------------------+
This is the structure of both tables, both databases are on the same server.
I will only get a value from Last Table
DLL
| derogation | CREATE TABLE `derogation` (
`xxx` char(10) NOT NULL,
`xxx` varchar(100) DEFAULT NULL,
`code` char(17) DEFAULT NULL,
`xxx` varchar(20) DEFAULT NULL,
`xxx` char(6) DEFAULT NULL,
`xxx` varchar(50) DEFAULT NULL,
`xxx` varchar(200) DEFAULT NULL,
`xxxx` varchar(200) DEFAULT NULL,
`xxxx` varchar(100) DEFAULT NULL,
`xxxx` datetime DEFAULT NULL,
`xxx` varchar(100) DEFAULT NULL,
`xxxx` varchar(20) DEFAULT NULL,
`xxx` varchar(50) DEFAULT NULL,
`xxx` varchar(10) DEFAULT NULL,
`xxx` datetime DEFAULT NULL,
`xxx` varchar(10) DEFAULT NULL,
`xxx` datetime DEFAULT NULL,
`xxx` datetime DEFAULT NULL,
`status` varchar(20) DEFAULT NULL,
`xxx` varchar(1000) DEFAULT NULL,
KEY `code_index_derogation` (`code`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
| Last | CREATE TABLE `Last` (
`code` char(17) DEFAULT NULL,
`xxx` decimal(10,2) DEFAULT NULL,
`Date` datetime DEFAULT NULL,
`xxxx` datetime DEFAULT NULL,
`xxxx` datetime DEFAULT NULL,
`xxxx` text DEFAULT NULL,
`xxxxx` datetime DEFAULT NULL,
`xxxx` char(6) DEFAULT NULL,
KEY `idx_Last_Code` (`code`),
KEY `idx_Last_xxx` (`xxx`),
KEY `code_index` (`code`),
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
you can use temporary tables, staging tables CTE or you can add indexes for the columns of the tables.
But using temporary tables, it's always an excelent choice to accelerate the excecution of the the SQL query.
(The problem is subtle, and often overlooked in this forum.)
Don't mix collations. You are joining on code, but the CHARACTER SET and COLLATION are different between the two tables. Suggest using `ALTER TABLE .. CONVERT TO .. to get them to be the same.
Other tips:
Use CHAR only for truly fixed-length columns. Use VARCHAR otherwise.
Have a PRIMARY KEY on every table.
Don't say LEFT JOIN if you really expect JOIN; it adds confusion to the reader.
I want to create a table so that I have an ID number that is based on the date, AND an ID as a unique, primary key.
Ie:
2015-2-1-1
2015-2-1-2
but, if I create:
2015-2-2-1
the counter should restart at 1.
I've tried using the following:
CREATE TABLE `invoices` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`date` date NOT NULL,
`po_id` int(11) unsigned DEFAULT NULL,
`description` varchar(256) NOT NULL,
`client_id` int(11) unsigned DEFAULT NULL,
`status` enum('unpaid','paid','partial') DEFAULT 'unpaid',
PRIMARY KEY (`id`,`date`),
UNIQUE KEY `id_UNIQUE` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=latin1;
But it doesn't work like I want.
If you want a two column primary key (date, id) and id that should auto increment starting from 1 each date. Just set date, for your primary column key, and id in second position in your key definition.
CREATE TABLE `invoices` (
`date` date NOT NULL,
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`po_id` int(11) unsigned DEFAULT NULL,
`description` varchar(256) NOT NULL,
`client_id` int(11) unsigned DEFAULT NULL,
`status` enum('unpaid','paid','partial') DEFAULT 'unpaid',
PRIMARY KEY (`date`, `id`)
) ENGINE=MyIsam DEFAULT CHARSET=latin1;
The internal key will be set as your example, but you will see two columns:
+----+------------+
| id | date |
+----+------------+
| 1 | 2012-01-01 |
| 2 | 2012-01-01 |
| 1 | 2012-01-02 |
| 2 | 2012-01-02 |
+----+------------+
EDIT: You have to use MyIsam format
simple query is taking long time around 630 sec to execute
performing full table scan.
please help me to rewrite the query and also suggest me if any indexes need to add.
Query:
mysql> explain SELECT count(DISTINCT(tab1.idnum)) as totalresults FROM (`tab1`) LEFT JOIN `tab2` ON tab2.idnum = tab1.col1id WHERE tab1.userid = '165258' AND `result` = 'correct' AND tab2.department = 'DEPT1' AND tab2.book = 2096 AND `quarantined` = 0;
Explain Plan:
+----+-------------+--------------+--------+------------------------------------+---------+---------+---------------------------+-------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+--------------+--------+------------------------------------+---------+---------+---------------------------+-------+-------------+
| 1 | SIMPLE | tab1 | ref | userid,col1id,result,userid_status | userid | 4 | const | 14720 | Using where |
| 1 | SIMPLE | tab2 | eq_ref | PRIMARY | PRIMARY | 4 | comp1.tab1.col1id | 1 | Using where |
+----+-------------+--------------+--------+------------------------------------+---------+---------+---------------------------+-------+-------------+
2 rows in set (0.00 sec)
Table structutre:
mysql> show create table tab1\G
*************************** 1. row ***************************
Table: tab1
Create Table: CREATE TABLE `tab1` (
`idnum` int(11) NOT NULL AUTO_INCREMENT,
`questid` int(11) NOT NULL DEFAULT '0',
`userid` int(11) NOT NULL DEFAULT '0',
`col1id` int(11) NOT NULL DEFAULT '0',
`result` enum('correct','incorrect') NOT NULL DEFAULT 'def1',
`answergiven` varchar(35) NOT NULL DEFAULT '0',
`timestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
`status` enum('calibrating','normal') NOT NULL DEFAULT 'def2',
`quarantined` tinyint(1) NOT NULL DEFAULT '0',
PRIMARY KEY (`idnum`),
KEY `questid` (`questid`),
KEY `userid` (`userid`),
KEY `col1id` (`col1id`),
KEY `result` (`result`),
KEY `userid_status` (`userid`,`status`),
KEY `questid_status` (`questid`,`status`),
KEY `timestamp` (`timestamp`)
) ENGINE=InnoDB AUTO_INCREMENT=143018786 DEFAULT CHARSET=latin1
1 row in set (0.00 sec)
mysql> show create table tab2\G
*************************** 1. row ***************************
Table: tab2
Create Table: CREATE TABLE `tab2` (
`idnum` int(11) NOT NULL AUTO_INCREMENT,
`userid` int(11) NOT NULL DEFAULT '0',
`timestarted` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`timefinished` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`questionlist` mediumtext NOT NULL,
`topics` mediumtext NOT NULL,
`totalnum` int(11) NOT NULL DEFAULT '0',
`completednum` int(11) NOT NULL DEFAULT '0',
`assignment` int(11) NOT NULL DEFAULT '0',
`department` varchar(255) NOT NULL DEFAULT '',
`book` int(11) NOT NULL DEFAULT '0',
`cqs` mediumtext NOT NULL,
`metatype` varchar(25) DEFAULT 'topic',
PRIMARY KEY (`idnum`),
KEY `userid` (`userid`),
KEY `assignment` (`assignment`)
) ENGINE=InnoDB AUTO_INCREMENT=13547403 DEFAULT CHARSET=latin1
1 row in set (0.00 sec)
You need a multi-column index, ie. one that spans userid AND col1id in tab1 at the same time. Try:
create index idx_usr_col1 on tab1(userid,col1id)
Try adding multi-column indices for MySQL to use:
ALTER TABLE `tab2` ADD INDEX idx_col1id_userid_result_quarantined (`col1id`, `userid`, `result`, `quarantined`);
ALTER TABLE `tab1` ADD INDEX idx_department_book (`department`, `book`);
Try this:
SELECT count(distinct result.idnum)) as totalresults FROM `tab1` as result
inner join (select distinct idnum from `tab2` where department = 'DEPT1' and book = 2096 ) as col11 ON col11.idnum = result.col1id
WHERE result.userid = '165258' AND `result` = 'correct' AND `quarantined` = 0;
The below query is taking around 10mins to 1 hr to execute. And due to this we are getting load spikes frequently. Can anyone please help rewrite the query in a more optimised way.
Query:
select count(*)
from t_tab6 tab1
left join t_tab6_element_tab2 tab2
on tab2.tab6_id = tab1.id
left join t_tab3 tab3
on tab1.create_tab3_id = tab3.id
left join t_tab4 tab4
on tab2.element_id = tab4.id and tab2.element_type_id = 1
left join t_tab7 tab5
on tab2.element_id = tab5.id and tab2.element_type_id = 2
where tab1.domain_id = 522
Explain plan:
+----+-------------+-----------+--------+-------------------------+-------------------------+---------+----------------------------+--------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-----------+--------+-------------------------+-------------------------+---------+----------------------------+--------+-------------+
| 1 | SIMPLE | tab1 | ref | domain_id_tab6_type_cd | domain_id_tab6_type_cd | 4 | const | 243430 | |
| 1 | SIMPLE | tab2 | ref | FK_tab6 | FK_tab6 | 4 | comp1.tab1.id | 2 | |
| 1 | SIMPLE | tab3 | eq_ref | PRIMARY | PRIMARY | 4 | comp1.tab1.create_tab3_id | 1 | Using index |
| 1 | SIMPLE | tab4 | ref | id | id | 4 | comp1.tab2.element_id | 1 | Using index |
| 1 | SIMPLE | tab5 | ref | id | id | 4 | comp1.tab2.element_id | 1 | Using index |
+----+-------------+-----------+--------+-------------------------+-------------------------+---------+----------------------------+--------+-------------+
5 rows in set (0.45 sec)
Tables structure:
mysql> show create table t_tab6_element_tab2\G
*************************** 1. row ***************************
Table: t_tab6_element_tab2
Create Table: CREATE TABLE `t_tab6_element_tab2` (
`id` int(255) NOT NULL AUTO_INCREMENT,
`element_type_id` int(11) NOT NULL,
`tab6_id` int(11) NOT NULL,
`element_id` int(11) NOT NULL,
`element_desc` varchar(500) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `FK_tab6` (`tab6_id`),
KEY `element_type_id_element_id` (`element_type_id`,`element_id`)
) ENGINE=InnoDB AUTO_INCREMENT=45901159 DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
mysql> show create table t_tab3\G
*************************** 1. row ***************************
Table: t_tab3
Create Table: CREATE TABLE `t_tab3` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`password` varchar(255) DEFAULT NULL,
`email` varchar(255) DEFAULT NULL,
`is_admin` int(11) DEFAULT NULL,
`phone` varchar(50) DEFAULT NULL,
`company` varchar(255) DEFAULT NULL,
`last_login` datetime DEFAULT NULL,
`state` int(11) DEFAULT NULL,
`validate_code` varchar(50) DEFAULT NULL,
`has_login` smallint(6) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1304 DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
mysql> show create table t_tab6\G
*************************** 1. row ***************************
Table: t_tab6
Create Table: CREATE TABLE `t_tab6` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`create_tab3_id` int(11) DEFAULT NULL,
`tab6_create_date` date DEFAULT NULL,
`tab6_type_cd` int(11) NOT NULL,
`tab6_desc` varchar(512) NOT NULL,
`IsGlobaltab6` int(2) DEFAULT NULL,
`tab6_start_date` datetime NOT NULL,
`tab6_end_date` datetime NOT NULL,
`job_id` int(11) DEFAULT NULL,
`domain_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `tab6_tab3_FK` (`create_tab3_id`),
KEY `domain_id_tab6_type_cd` (`domain_id`,`tab6_type_cd`)
) ENGINE=InnoDB AUTO_INCREMENT=8586007 DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
mysql> show create table t_tab4\G
*************************** 1. row ***************************
Table: t_tab4
Create Table: CREATE TABLE `t_tab4` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`tab4_name` varchar(255) DEFAULT NULL,
`tab4_value` varchar(255) DEFAULT NULL,
`type` int(11) DEFAULT NULL,
`description` varchar(2000) DEFAULT NULL,
`own_domain_id` int(11) DEFAULT NULL,
`rank_check` int(11) DEFAULT NULL,
`rank1` int(11) DEFAULT NULL,
`rank2` int(11) DEFAULT NULL,
`rank3` int(11) DEFAULT NULL,
`yesterday_entrances` int(11) DEFAULT NULL,
`week_entrances` int(11) DEFAULT NULL,
`current_ctr` float(16,4) DEFAULT NULL,
`monthly_search_volume` int(11) DEFAULT NULL,
`avg_monthly_search_volume` int(11) DEFAULT NULL,
`traffic_increase` int(11) DEFAULT NULL,
`rank_improvement` int(11) DEFAULT NULL,
`rank_update_date` date DEFAULT NULL,
`top_rank_tab5_id` int(11) DEFAULT NULL,
`frequency` int(10) DEFAULT '1',
`score` float DEFAULT NULL,
`create_date` datetime DEFAULT NULL,
`bing_rank1` int(10) DEFAULT NULL,
`bing_rank2` int(10) DEFAULT NULL,
`yesterday_bing_entrances` int(11) DEFAULT NULL,
`bing_rank_improvement` int(11) DEFAULT NULL,
KEY `id` (`id`),
KEY `tab4_name` (`tab4_name`),
KEY `own_domain_id` (`own_domain_id`,`rank_check`),
KEY `rank_check` (`rank_check`)
) ENGINE=InnoDB AUTO_INCREMENT=670267018 DEFAULT CHARSET=utf8
/*!50100 PARTITION BY RANGE (`rank_check`)
(PARTITION p0 VALUES LESS THAN (0) ENGINE = InnoDB,
PARTITION p1 VALUES LESS THAN (1) ENGINE = InnoDB,
PARTITION p2 VALUES LESS THAN (2) ENGINE = InnoDB,
PARTITION pEOW VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */
1 row in set (0.00 sec)
mysql> show create table t_tab7\G
*************************** 1. row ***************************
Table: t_tab7
Create Table: CREATE TABLE `t_tab7` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`own_domain_id` int(11) DEFAULT NULL,
`url` varchar(2000) NOT NULL,
`create_date` datetime DEFAULT NULL,
`friendly_name` varchar(255) DEFAULT NULL,
`section_name_id` int(11) DEFAULT NULL,
`type` int(11) DEFAULT NULL,
`status` int(11) DEFAULT NULL,
`week_entrances` int(11) DEFAULT NULL,
`week_bounces` int(11) DEFAULT NULL,
`canonical_url_id` int(11) DEFAULT NULL,
KEY `id` (`id`),
KEY `urlindex` (`url`(255)),
KEY `own_domain_id_type_status` (`own_domain_id`,`type`,`status`),
KEY `canonical_url_id` (`canonical_url_id`),
KEY `type` (`type`,`status`)
) ENGINE=InnoDB AUTO_INCREMENT=237034388 DEFAULT CHARSET=utf8
/*!50100 PARTITION BY RANGE (`type`)
(PARTITION p0 VALUES LESS THAN (0) ENGINE = InnoDB,
PARTITION p1 VALUES LESS THAN (1) ENGINE = InnoDB,
PARTITION p2 VALUES LESS THAN (2) ENGINE = InnoDB,
PARTITION pEOW VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */
1 row in set (0.01 sec)
Try below
select count(*)
from (Select id,create_tab3_id from tab6 where domain_id = 522) as tab1
left join tab6_element_tab2 tab2
on tab2.tab1nt_id = tab1.id
left join t_tab3 tab3
on tab1.create_tab3_id = tab3.id
left join t_tab4 tab4
on tab2.element_id = tab4.id and tab2.element_type_id = 1
left join t_tab7 tab5
on tab2.element_id = tab5.id and tab2.element_type_id = 2
Remove left join t_tab3 tab3 if you are using for count only and if possible add domain type check in where clause
Define an index on the column used in your condition:
create index t_tab6_domain_id_index on t_tab6(domain_id);
The query itself seems fine.
We have a central login that we use to support multiple websites. To store our users' data we have an accounts table which stores each user account and then users tables for each site for site specific information. We also have a simple connections table which stores the connections between users.
We noticed that one query that is joining the tables on their primary key user_id is executing slowly. I'm hoping that some SQL expert out there can explain why it's using WHERE to search the users_site1 table and suggest how we can optimize it. Here is the slow query & the explain results:
mysql> explain select a.username,a.first_name,a.last_name,a.organization_name,a.organization,a.city,a.state,a.zip,a.country,a.profile_photo,a.facebook_id,a.twitter_id,u.reviews from accounts a join users_site1 u ON a.user_id=u.user_id where a.user_id IN (select cid2 from connections where cid1=10001006 AND type="MM" AND status="A") OR a.user_id IN (select cid1 from connections where cid2=10001006 AND type="MM" AND status="A") order by RAND() LIMIT 4;
+----+--------------------+-------------+--------+-------------------+---------+---------+-----------------------+-------+----------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+--------------------+-------------+--------+-------------------+---------+---------+-----------------------+-------+----------------------------------------------+
| 1 | PRIMARY | u | ALL | PRIMARY | NULL | NULL | NULL | 79783 | Using where; Using temporary; Using filesort |
| 1 | PRIMARY | a | eq_ref | PRIMARY | PRIMARY | 4 | exampledb.u.user_id | 1 | |
| 3 | DEPENDENT SUBQUERY | connections | ref | PRIMARY,cid1,cid2 | cid2 | 6 | const,const | 2 | Using where |
| 2 | DEPENDENT SUBQUERY | connections | ref | PRIMARY,cid1,cid2 | cid1 | 6 | const,const | 1 | Using where |
+----+--------------------+-------------+--------+-------------------+---------+---------+-----------------------+-------+----------------------------------------------+
4 rows in set (0.00 sec)
Here are the definitions for each table:
CREATE TABLE `accounts` (
`user_id` int(9) unsigned NOT NULL AUTO_INCREMENT,
`username` varchar(40) DEFAULT NULL,
`facebook_id` bigint(15) unsigned DEFAULT NULL,
`facebook_username` varchar(30) DEFAULT NULL,
`password` varchar(20) DEFAULT NULL,
`profile_photo` varchar(100) DEFAULT NULL,
`first_name` varchar(40) DEFAULT NULL,
`middle_name` varchar(40) DEFAULT NULL,
`last_name` varchar(40) DEFAULT NULL,
`suffix_name` char(3) DEFAULT NULL,
`organization_name` varchar(100) DEFAULT NULL,
`organization` tinyint(1) unsigned DEFAULT NULL,
`address` varchar(200) DEFAULT NULL,
`city` varchar(40) DEFAULT NULL,
`state` varchar(20) DEFAULT NULL,
`zip` varchar(10) DEFAULT NULL,
`province` varchar(40) DEFAULT NULL,
`country` int(3) DEFAULT NULL,
`latitude` decimal(11,7) DEFAULT NULL,
`longitude` decimal(12,7) DEFAULT NULL,
`phone` varchar(20) DEFAULT NULL,
`sex` char(1) DEFAULT NULL,
`birthday` date DEFAULT NULL,
`about_me` varchar(2000) DEFAULT NULL,
`activities` varchar(300) DEFAULT NULL,
`website` varchar(100) DEFAULT NULL,
`email` varchar(150) DEFAULT NULL,
`referrer` int(4) unsigned DEFAULT NULL,
`referredid` int(9) unsigned DEFAULT NULL,
`verify` int(6) DEFAULT NULL,
`status` char(1) DEFAULT 'R',
`created` datetime DEFAULT NULL,
`verified` datetime DEFAULT NULL,
`activated` datetime DEFAULT NULL,
`network` datetime DEFAULT NULL,
`deleted` datetime DEFAULT NULL,
`logins` int(6) unsigned DEFAULT '0',
`api_logins` int(6) unsigned DEFAULT '0',
`last_login` datetime DEFAULT NULL,
`last_update` datetime DEFAULT NULL,
`private` tinyint(1) unsigned DEFAULT NULL,
`ip` varchar(20) DEFAULT NULL,
PRIMARY KEY (`user_id`),
UNIQUE KEY `username` (`username`),
KEY `facebook_id` (`facebook_id`),
KEY `status` (`status`),
KEY `state` (`state`)
);
CREATE TABLE `users_site1` (
`user_id` int(9) unsigned NOT NULL,
`facebook_id` bigint(15) unsigned DEFAULT NULL,
`facebook_username` varchar(30) DEFAULT NULL,
`facebook_publish` tinyint(1) unsigned DEFAULT NULL,
`facebook_checkin` tinyint(1) unsigned DEFAULT NULL,
`facebook_offline` varchar(300) DEFAULT NULL,
`twitter_id` varchar(60) DEFAULT NULL,
`twitter_secret` varchar(50) DEFAULT NULL,
`twitter_username` varchar(20) DEFAULT NULL,
`type` char(1) DEFAULT 'M',
`referrer` int(4) unsigned DEFAULT NULL,
`referredid` int(9) unsigned DEFAULT NULL,
`session` varchar(60) DEFAULT NULL,
`api_session` varchar(60) DEFAULT NULL,
`status` char(1) DEFAULT 'R',
`created` datetime DEFAULT NULL,
`verified` datetime DEFAULT NULL,
`activated` datetime DEFAULT NULL,
`deleted` datetime DEFAULT NULL,
`logins` int(6) unsigned DEFAULT '0',
`api_logins` int(6) unsigned DEFAULT '0',
`last_login` datetime DEFAULT NULL,
`last_update` datetime DEFAULT NULL,
`ip` varchar(20) DEFAULT NULL,
PRIMARY KEY (`user_id`)
);
CREATE TABLE `connections` (
`cid1` int(9) unsigned NOT NULL DEFAULT '0',
`cid2` int(9) unsigned NOT NULL DEFAULT '0',
`cid3` int(9) unsigned NOT NULL DEFAULT '0',
`type` char(2) NOT NULL,
`status` char(1) NOT NULL,
`created` datetime DEFAULT NULL,
`updated` datetime DEFAULT NULL,
PRIMARY KEY (`cid1`,`cid2`,`type`,`cid3`),
KEY `cid1` (`cid1`,`type`),
KEY `cid2` (`cid2`,`type`)
);
Instead of WHERE a.userid IN( ... ) OR a.userid IN( ... ) you should use another join:
select
a.username,a.first_name,a.last_name,a.organization_name,a.organization,a.city,
a.state,a.zip,a.country,a.profile_photo,a.facebook_id,a.twitter_id,u.reviews
from accounts a
join users_site1 u ON a.user_id=u.user_id
join ( select cid2 as id from connections
where cid1=10001006 AND type="MM" AND status="A"
union
select cid1 as id from connections
where cid2=10001006 AND type="MM" AND status="A" ) c
on a.user_id = c.id
order by RAND() LIMIT 4;
have you tried remove order by RAND() and run again?
my result is below:
+----+--------------------+-------------+----------------+-------------------+---------+---------+------------------+------+----------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+--------------------+-------------+----------------+-------------------+---------+---------+------------------+------+----------------------------------------------+
| 1 | PRIMARY | a | ALL | PRIMARY | NULL | NULL | NULL | 2 | Using where; Using temporary; Using filesort |
| 1 | PRIMARY | u | ALL | PRIMARY | NULL | NULL | NULL | 2 | Using where; Using join buffer |
| 3 | DEPENDENT SUBQUERY | connections | index_subquery | PRIMARY,cid1,cid2 | PRIMARY | 14 | func,const,const | 1 | Using where |
| 2 | DEPENDENT SUBQUERY | connections | ref | PRIMARY,cid1,cid2 | PRIMARY | 14 | const,func,const | 1 | Using where |
+----+--------------------+-------------+----------------+-------------------+---------+---------+------------------+------+----------------------------------------------+
I am not a MySQL guru by any means but been have involved more than once in optimization of high performance applications, though I was more on the implementation end of the optimisation process versus finding what needed to be optimized.
The firt thing I see is the subqueries seem efficient, but the way the first query is run with this where clause: ... where a.user_id IN (select cid2 ...) or a.user_id IN (select cid1 from ...) is a performance killer in my very humble opinion.
The first thing I would try to optimise performance, consider trying join decomposition , split your request in 2 or even 3 queries. The code is less pretty, but the db will be able to work more efficiently. It is a myth that doing everything in one query is better.
What can this bring you? Caching will be more efficient, if using MyISam tables the locking srategy is more efficient when you have less tables in your query, and you will reduce the redundant row accesses. If you can get your main query ( that would be the last one if you decompose ) from Using where; Using temporary; Using filesort, you will have much faster response.
Profile the different options you try with SHOW SESSION STATUS and FLUSH status, also you can disable caching to get true comparison of different options you try by adding SQL_NO_CACHE in your query, ie SELSECT SQL_NO_CACHE a.username ... etc..
Profiling and measuring the results is the only way you will be able to determine the performance gains. Unfortunately this step is often overlooked.
Good luck!