Is this the best performance using mysql count on multiple joins - mysql

I have a DB with the following tables:
employee
company
lt_employee_title
Employees can have multiple titles and companies can have multiple employees.
I'm trying to search on the lt_employee_title table and the company table and get employee_id from the employee table.
The table structures:
CREATE TABLE `employee` (
`employee_id` int(11) NOT NULL AUTO_INCREMENT,
`company_id` int(11) DEFAULT NULL,
PRIMARY KEY (`employee_id`),
KEY `employee_id` (`company_id`)
) ENGINE=InnoDB;
CREATE TABLE `company` (
`company_id` int(11) NOT NULL AUTO_INCREMENT,
`URL` varchar(100) DEFAULT NULL,
`company_name` varchar(100) DEFAULT NULL,
`date_created` date DEFAULT NULL,
`date_updated` datetime DEFAULT NULL,
`address1` varchar(45) DEFAULT NULL,
`address2` varchar(45) DEFAULT NULL,
`phone` varchar(20) DEFAULT NULL,
`phone2` varchar(20) DEFAULT NULL,
`fax` varchar(20) DEFAULT NULL,
`city` varchar(45) DEFAULT NULL,
`major_city_id` int(11) DEFAULT NULL,
`region_code` varchar(10) DEFAULT NULL,
`zip` varchar(15) DEFAULT NULL,
`country_code` varchar(2) DEFAULT NULL,
`archived` tinyint(4) NOT NULL DEFAULT '0',
`enabled` enum('yes','no') DEFAULT 'yes',
PRIMARY KEY (`company_id`),
KEY `country_code` (`country_code`),
KEY `employee` (`number_of_employees_id`),
KEY `phone` (`phone`(3)),
KEY `state` (`region_code`),
KEY `archived` (`archived`)
) ENGINE=InnoDB;
CREATE TABLE `lt_employee_title` (
`employee_id` int(11) NOT NULL,
`title_id` int(11) NOT NULL,
UNIQUE KEY `unique_field` (`employee_id`,`title_id`),
KEY `employee_id` (`employee_id`),
KEY `title_id` (`title_id`),
KEY `both` (`title_id`,`employee_id`),
KEY `both2` (`employee_id`,`title_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8$$;
This query is fast:
SELECT SQL_NO_CACHE
*
FROM lt_employee_title AS let
JOIN employee AS ee
ON ee.employee_id = let.employee_id
JOIN company AS com
ON com.company_id = ee.company_id
WHERE let.title_id = 9
AND com.region_code IN('AL', 'AK', 'AZ')
AND com.archived = 0
LIMIT 125;
But these are not:
SELECT SQL_NO_CACHE
COUNT(*)
FROM lt_employee_title AS let
...
SELECT SQL_NO_CACHE SQL_CALC_FOUND_ROWS
*
FROM lt_employee_title AS let
...
The difference of adding any type of count moves the time from 0.016 seconds to 4.0 seconds. We have about 250,000 titles, and 900,000 companiy entries and over 1 million employee records but will be growing.
When I add in count() or SQL_CALC_FOUND_ROWS or ORDER BY com.number_of_employees_id, the EXPLAIN is using temp tables and file_sort which is why the speed decrease. Is there a way to do this sql more efficiently?
EXPLAIN WITH "SQL_CALC_FOUND_ROWS"
1 SIMPLE company ref PRIMARY,state,created,updated,employee_number,archived state 33 const 210864 Using where; Using filesort
1 SIMPLE employee ref PRIMARY,employee_id,created,updated employee_id 5 lead411_main.company.company_id 1 Using where; Using index
1 SIMPLE lt_employee_title eq_ref unique_field,employee_id,title_id,both,both2 unique_field 8 lead411_main.employee.employee_id,const 1 Using index
EXPLAIN WITH OUT "SQL_CALC_FOUND_ROWS"
1 SIMPLE company index PRIMARY,state,created,updated,employee_number,archived employee 5 986 Using where
1 SIMPLE employee ref PRIMARY,employee_id,created,updated employee_id 5 lead411_main.company.company_id 1 Using where; Using index
1 SIMPLE lt_employee_title eq_ref unique_field,employee_id,title_id,both,both2 unique_field 8 lead411_main.employee.employee_id,const 1 Using index

Related

Why is this SQL query extremely slow?

UPDATE: seems that the Query Cache is not activated, otherwise the performance would be much better from the second execution of the same query, since MySQL should have cached it already. I have MariaDB version: 10.2.41-
Protocol version: 10 , indeed the Query Cache is disabled by default starting with MariaDB 10.1.7.
Is it a good idea to enable it on my VPS config? Or i better upgrade it first?
I have a MySQL query performing very slowly on a CentOS VPS with 1GB RAM and 1 CPU Core.
The query takes 400 - 900 ms to execute (!!), which i want to figure out how to optimize.
It's over several tables, some of them pretty huge (Wordpress' wp_postmeta for example).
But apparently all columns involved are indexed properly, so i'm asking for advice on what to do, or if the only optimization possible is to upgrade the VPS.
Thanks in advance!
Here is the query and the EXPLAIN output
EXPLAIN SELECT c.post_id AS wc_variation_id,v.original_price_rand,v.price,c.meta_value AS color,s.meta_value AS size,bp.tier,t.discount_percent,MAX(IFNULL(tag.extra_price_tag,0)) AS extra_price_tag,MAX(IFNULL(lab.extra_price_label,0)) AS extra_price_label,
i.uri,i.branded,i.design_cost,ib.uri AS uri_back,ib.branded AS branded_back,ib.design_cost AS design_cost_back
FROM wp_postmeta c
JOIN brandly_tiers_bp_balances bp
JOIN brandly_tiers t ON t.role_name=bp.tier
JOIN wix_images i
JOIN wix_images_back ib
JOIN wix_imported_product_variations v ON v.wc_id=c.post_id
LEFT JOIN brandly_reseller_tags rt ON rt.user_id=bp.user_id
LEFT JOIN brandly_reseller_branded_packaging_sizes tag ON tag.size_label=rt.size_label
LEFT JOIN brandly_reseller_labels rl ON rl.user_id=bp.user_id
LEFT JOIN brandly_reseller_branded_packaging_sizes lab ON lab.size_label=rl.size_label
JOIN wp_postmeta s ON s.post_id=c.post_id
WHERE c.post_id IN (SELECT DISTINCT(wc_id) FROM wix_imported_product_variations WHERE wc_product_id = 181189)
AND s.meta_key = 'attribute_pa_size'
AND c.meta_key = 'attribute_pa_colour'
AND i.wix_variation_id=v.wix_id
AND ib.wix_variation_id=v.wix_id
AND v.store_id=36
AND bp.user_id=11
GROUP BY c.post_id
ORDER BY color,size
Output:
id
select_type
table
type
possible_keys
key
key_len
ref
rows
Extra
1
PRIMARY
bp
const
PRIMARY,tier
PRIMARY
8
const
1
Using temporary; Using filesort
1
PRIMARY
t
const
PRIMARY
PRIMARY
52
const
1
1
PRIMARY
wix_imported_product_variations
ref
wc_product_id,wc_id
wc_product_id
8
const
3
Start temporary
1
PRIMARY
rt
ref
PRIMARY
PRIMARY
8
const
5
Using index
1
PRIMARY
tag
eq_ref
PRIMARY
PRIMARY
32
brandly_xvfkg.rt.size_label
1
Using where
1
PRIMARY
c
ref
post_id,meta_key
post_id
8
brandly_xvfkg.wix_imported_product_variations.wc_id
14
Using index condition; Using where; End temporary
1
PRIMARY
v
ref
PRIMARY,store_id,wc_id
wc_id
8
brandly_xvfkg.c.post_id
1
Using index condition; Using where
1
PRIMARY
ib
ref
wix_variation_id
wix_variation_id
103
brandly_xvfkg.v.wix_id
3
1
PRIMARY
i
ref
wix_variation_id
wix_variation_id
103
brandly_xvfkg.v.wix_id
3
1
PRIMARY
s
ref
post_id,meta_key
post_id
8
brandly_xvfkg.c.post_id
14
Using where
1
PRIMARY
rl
ref
PRIMARY
PRIMARY
8
const
5
Using index
1
PRIMARY
lab
eq_ref
PRIMARY
PRIMARY
32
brandly_xvfkg.rl.size_label
1
Using where
EDIT: The subquery takes 0.0005 seconds , so it's not the culprit
EDIT2: the wp_postmeta table has 1709642 records and it's MyISAM:
SHOW CREATE TABLE `wp_postmeta`;
CREATE TABLE `wp_postmeta` (
`meta_id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`post_id` bigint(20) unsigned NOT NULL DEFAULT 0,
`meta_key` varchar(255) DEFAULT NULL,
`meta_value` longtext DEFAULT NULL,
PRIMARY KEY (`meta_id`),
KEY `post_id` (`post_id`),
KEY `meta_key` (`meta_key`(191))
) ENGINE=MyISAM AUTO_INCREMENT=3945402 DEFAULT CHARSET=utf8
EDIT3: actually all tables are MyISAM except wix_images, wix_images_back, wix_imported_product_variations which are innoDB
EDIT4: just converted all tables to innoDB. The performance is better now, it takes 200-400 ms. Still slow though.
EDIT5: EXPLAIN output changed a bit now, after switching the tables to innoDB. See https://codebeautify.org/htmlviewer/y225302bb
EDIT6: here are the definitions of the tables involved
CREATE TABLE `wp_postmeta` (
`meta_id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`post_id` bigint(20) unsigned NOT NULL DEFAULT 0,
`meta_key` varchar(255) DEFAULT NULL,
`meta_value` longtext DEFAULT NULL,
PRIMARY KEY (`meta_id`),
KEY `post_id` (`post_id`),
KEY `meta_key` (`meta_key`(191))
) ENGINE=InnoDB AUTO_INCREMENT=3945402 DEFAULT CHARSET=utf8
CREATE TABLE `brandly_tiers_bp_balances` (
`user_id` bigint(20) NOT NULL,
`bp_balance` bigint(20) NOT NULL DEFAULT 0,
`bp_pending_balance` bigint(20) NOT NULL DEFAULT 0,
`tier` varchar(50) COLLATE latin1_general_ci NOT NULL DEFAULT 'Earth',
`tier_change_ts` bigint(20) DEFAULT NULL,
PRIMARY KEY (`user_id`),
KEY `tier` (`tier`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci
CREATE TABLE `brandly_tiers` (
`role_name` varchar(50) COLLATE latin1_general_ci NOT NULL,
`bp_threshold` int(11) NOT NULL DEFAULT 0,
`discount_percent` smallint(6) NOT NULL,
`bp_percent_branded_orders` smallint(6) NOT NULL,
`bp_percent_bulk_orders` smallint(6) NOT NULL,
`bp_percent_courier` smallint(6) NOT NULL,
`bp_percent_bulk_branded_packaging` smallint(6) NOT NULL,
`bp_percent_monthly_subscription_fee` smallint(6) NOT NULL,
`bulk_order_minimum_quantity` int(11) NOT NULL DEFAULT 10,
`bp_bulk_order_cap` int(11) NOT NULL DEFAULT 7500,
`tier_monthly_subscription_price` int(11) NOT NULL DEFAULT 0,
PRIMARY KEY (`role_name`),
UNIQUE KEY `bp_threshold` (`bp_threshold`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci
CREATE TABLE `wix_images` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`filename` text COLLATE latin1_general_ci NOT NULL,
`uri` longtext COLLATE latin1_general_ci NOT NULL,
`background_image_uri` longtext COLLATE latin1_general_ci NOT NULL,
`branded` tinyint(1) DEFAULT 0,
`wix_id` varchar(100) COLLATE latin1_general_ci DEFAULT NULL,
`wix_product_id` varchar(100) COLLATE latin1_general_ci DEFAULT NULL,
`wix_variation_id` varchar(100) COLLATE latin1_general_ci DEFAULT NULL,
`design_cost` decimal(18,2) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `wix_id` (`wix_id`),
KEY `wix_product_id` (`wix_product_id`),
KEY `wix_variation_id` (`wix_variation_id`),
KEY `branded` (`branded`),
KEY `background_image_uri` (`background_image_uri`(8))
) ENGINE=InnoDB AUTO_INCREMENT=10680 DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci
CREATE TABLE `wix_images_back` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`filename` text COLLATE latin1_general_ci NOT NULL,
`uri` longtext COLLATE latin1_general_ci NOT NULL,
`background_image_uri` longtext COLLATE latin1_general_ci NOT NULL,
`branded` tinyint(1) DEFAULT 0,
`wix_id` varchar(100) COLLATE latin1_general_ci DEFAULT NULL,
`wix_product_id` varchar(100) COLLATE latin1_general_ci DEFAULT NULL,
`wix_variation_id` varchar(100) COLLATE latin1_general_ci DEFAULT NULL,
`design_cost` decimal(18,2) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `wix_id` (`wix_id`),
KEY `wix_product_id` (`wix_product_id`),
KEY `wix_variation_id` (`wix_variation_id`),
KEY `branded` (`branded`),
KEY `background_image_uri` (`background_image_uri`(8))
) ENGINE=InnoDB AUTO_INCREMENT=7733 DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci
CREATE TABLE `wix_imported_product_variations` (
`wix_id` varchar(100) COLLATE latin1_general_ci NOT NULL,
`store_id` int(11) NOT NULL,
`wc_id` bigint(20) NOT NULL,
`wc_product_id` bigint(20) NOT NULL,
`sku` varchar(100) COLLATE latin1_general_ci NOT NULL,
`price` decimal(18,2) NOT NULL,
`original_price_rand` decimal(18,2) NOT NULL,
`has_markup` tinyint(1) DEFAULT 1,
`wix_image_id` varchar(1000) COLLATE latin1_general_ci NOT NULL,
`imported_at` datetime DEFAULT NULL,
`tmp_design_image` text COLLATE latin1_general_ci DEFAULT NULL,
`tmp_branded` tinyint(1) DEFAULT NULL,
`tmp_design_cost` decimal(18,2) DEFAULT NULL,
`tmp_design_image_back` text COLLATE latin1_general_ci DEFAULT NULL,
`tmp_branded_back` tinyint(1) DEFAULT NULL,
`tmp_design_cost_back` decimal(18,2) DEFAULT NULL,
PRIMARY KEY (`wix_id`),
KEY `sku` (`sku`),
KEY `store_id` (`store_id`),
KEY `has_markup` (`has_markup`),
KEY `imported_at` (`imported_at`),
KEY `wc_product_id` (`wc_product_id`),
KEY `wc_id` (`wc_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci
CREATE TABLE `brandly_reseller_tags` (
`user_id` bigint(20) NOT NULL,
`size_label` varchar(30) COLLATE latin1_general_ci NOT NULL,
`image_front1` mediumtext COLLATE latin1_general_ci NOT NULL,
`image_back1` mediumtext COLLATE latin1_general_ci NOT NULL,
`image_front2` mediumtext COLLATE latin1_general_ci NOT NULL,
`image_back2` mediumtext COLLATE latin1_general_ci NOT NULL,
`image_front3` mediumtext COLLATE latin1_general_ci NOT NULL,
`image_back3` mediumtext COLLATE latin1_general_ci NOT NULL,
`default_index` int(11) DEFAULT NULL,
`design_cost` decimal(18,2) DEFAULT NULL,
PRIMARY KEY (`user_id`,`size_label`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci
CREATE TABLE `brandly_reseller_labels` (
`user_id` bigint(20) NOT NULL,
`size_label` varchar(30) COLLATE latin1_general_ci NOT NULL,
`image_front1` mediumtext COLLATE latin1_general_ci NOT NULL,
`image_back1` mediumtext COLLATE latin1_general_ci NOT NULL,
`image_front2` mediumtext COLLATE latin1_general_ci NOT NULL,
`image_back2` mediumtext COLLATE latin1_general_ci NOT NULL,
`image_front3` mediumtext COLLATE latin1_general_ci NOT NULL,
`image_back3` mediumtext COLLATE latin1_general_ci NOT NULL,
`default_index` int(11) DEFAULT NULL,
`design_cost` decimal(18,2) DEFAULT NULL,
PRIMARY KEY (`user_id`,`size_label`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci
CREATE TABLE `brandly_reseller_branded_packaging_sizes` (
`size_label` varchar(30) COLLATE latin1_general_ci NOT NULL,
`size1_cm` int(11) NOT NULL,
`size2_cm` int(11) NOT NULL,
`size3_cm` int(11) NOT NULL,
`is_bag` tinyint(1) DEFAULT NULL,
`max_weight_kg` decimal(18,2) NOT NULL,
`extra_price` decimal(18,2) NOT NULL,
`extra_price_gift` decimal(18,2) NOT NULL,
`extra_price_tag` decimal(18,2) NOT NULL,
`extra_price_label` decimal(18,2) NOT NULL,
PRIMARY KEY (`size_label`),
KEY `size1_cm` (`size1_cm`),
KEY `size2_cm` (`size2_cm`),
KEY `size3_cm` (`size3_cm`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci
EDIT7:
moved the ON conditions from the JOINs to the WHERE. Execution time 200-400ms like before.
EXPLAIN SELECT c.post_id AS wc_variation_id,v.original_price_rand,v.price,c.meta_value AS color,s.meta_value AS size,bp.tier,t.discount_percent,MAX(IFNULL(tag.extra_price_tag,0)) AS extra_price_tag,MAX(IFNULL(lab.extra_price_label,0)) AS extra_price_label,
i.uri,i.branded,i.design_cost,ib.uri AS uri_back,ib.branded AS branded_back,ib.design_cost AS design_cost_back
FROM wp_postmeta c
JOIN brandly_tiers_bp_balances bp
JOIN brandly_tiers t
JOIN wix_images i
JOIN wix_images_back ib
JOIN wix_imported_product_variations v
LEFT JOIN brandly_reseller_tags rt ON rt.user_id=bp.user_id
LEFT JOIN brandly_reseller_branded_packaging_sizes tag ON tag.size_label=rt.size_label
LEFT JOIN brandly_reseller_labels rl ON rl.user_id=bp.user_id
LEFT JOIN brandly_reseller_branded_packaging_sizes lab ON lab.size_label=rl.size_label
JOIN wp_postmeta s
WHERE c.post_id IN (SELECT DISTINCT(wc_id) FROM wix_imported_product_variations WHERE wc_product_id = 181189)
AND s.meta_key = 'attribute_pa_size'
AND c.meta_key = 'attribute_pa_colour'
AND i.wix_variation_id=v.wix_id
AND ib.wix_variation_id=v.wix_id
AND v.store_id=36
AND bp.user_id=11
AND s.post_id=c.post_id
AND t.role_name=bp.tier
AND v.wc_id=c.post_id
GROUP BY c.post_id
ORDER BY color,size
EXPLAIN output
id
select_type
table
type
possible_keys
key
key_len
ref
rows
Extra
1
PRIMARY
bp
const
PRIMARY,tier
PRIMARY
8
const
1
Using temporary; Using filesort
1
PRIMARY
t
const
PRIMARY
PRIMARY
52
const
1
1
PRIMARY
wix_imported_product_variations
ref
wc_product_id,wc_id
wc_product_id
8
const
3
Start temporary
1
PRIMARY
rt
ref
PRIMARY
PRIMARY
8
const
5
Using index
1
PRIMARY
tag
eq_ref
PRIMARY
PRIMARY
32
brandly_xvfkg.rt.size_label
1
Using where
1
PRIMARY
c
ref
post_id,meta_key
post_id
8
brandly_xvfkg.wix_imported_product_variations.wc_id
8
Using index condition; Using where; End temporary
1
PRIMARY
v
ref
PRIMARY,store_id,wc_id
wc_id
8
brandly_xvfkg.c.post_id
1
Using index condition; Using where
1
PRIMARY
ib
ref
wix_variation_id
wix_variation_id
103
brandly_xvfkg.v.wix_id
3
1
PRIMARY
i
ref
wix_variation_id
wix_variation_id
103
brandly_xvfkg.v.wix_id
3
1
PRIMARY
s
ref
post_id,meta_key
post_id
8
brandly_xvfkg.v.wc_id
8
Using index condition; Using where
1
PRIMARY
rl
ref
PRIMARY
PRIMARY
8
const
5
Using index
1
PRIMARY
lab
eq_ref
PRIMARY
PRIMARY
32
brandly_xvfkg.rl.size_label
1
Using where
Spending more money on a bigger server is unlikely to do you much good.
200-400ms for a query like this is not bad. There's probably no SQL magic that will get it to under 100ms; it's doing a lot. Often the words extremely slow refer to queries that take minutes or longer.
MAX(IFNULL(column, 0)) yields precisely the same result as MAX(column) as long as all values of column are positive.. Aggregate functions skip over nulls. You might be able to simplify the two places you use that expression.
Your query is hard to reason about. If this were my query I would rewrite it to get rid of the short table aliases, and rather spell them out. And, I would rewrite it so every JOIN (both LEFT and ordinary) had an ON-clause with it. Notice that ON-clauses can be compound:
FROM a
JOIN wp_postmeta ON a.id = wp_postmeta.postid
AND wp_postmeta.meta_key = 'attribute_pa_size'
That's a query pattern we WordPress hackers instantly recognize.
For ordinary JOINs, moving ON-clauses to WHERE-clauses has no effect on execution plans.
Your join types, in your plan, are all "const", "eq-ref", or "ref". That is very good.
There's a field-proven rework of WordPress's postmeta table indexes. Your postmeta table is big enough -- almost four megarows -- that you probably can use it. It changes the primary key to a compound key that meets the requirement of your query pattern. Yours is a common pattern in WooCommerce installations. It is this for MySQL 5.7 and above.
ALTER TABLE wp_postmeta
ADD UNIQUE KEY meta_id (meta_id),
DROP PRIMARY KEY,
ADD PRIMARY KEY (post_id, meta_key, meta_id),
DROP KEY meta_key,
ADD KEY meta_key (meta_key, meta_value(32), post_id, meta_id),
ADD KEY meta_value (meta_value(32), meta_id),
DROP KEY post_id;
The Index WP MySQL For Speed plugin is designed to install this set of indexes for you, and do its best with MySQL / MariaDB 5.5 and up.
I don't see any big problems with indexing on your non-WordPress tables. There may be some opportunities for compound covering indexes, but, again, your query is hard to read.
95% of systems are better off with the Query Cache turned off. Remember that any modification to a table causes the QC to purge all entries for that table. If there are a lot of writes to a table, that could be a lot of CPU cycles for purging.
If you have only 1GB of RAM, there is not much room for the QC; use the room for InnoDB's buffer_pool instead. When you changed from MyISAM did you lower key_buffer_size and raise innodb_buffer_pool_size?
Some of these composite indexes may help:
c: INDEX(post_id, meta_key, meta_value)
v: INDEX(wix_id, store_id, wc_id, original_price_rand, price)
s: INDEX(meta_key, post_id, meta_value)
bp: INDEX(user_id, tier)
t: INDEX(role_name, discount_percent)
tag: INDEX(size_label, extra_price_tag)
lab: INDEX(size_label, extra_price_label)
i: INDEX(wix_variation_id, uri, branded, design_cost)
ib: INDEX(wix_variation_id, uri, branded, design_cost)
rt: INDEX(user_id, size_label)
rl: INDEX(user_id, size_label)
When adding a composite index, DROP index(es) with the same leading columns.
That is, when you have both INDEX(a) and INDEX(a,b), toss the former.

MySql Using filesort when i using a group by

I have a little problem with optimizing a query, I have 2 tables, one which records the participation (participation) in a quiz, and the other which records the answer to each question (participation_rep), participation is linked to the campaign table.
SELECT count(DISTINCT p.id) as number_of_participation
FROM participation_rep prep
INNER JOIN participation p
ON p.id = prep.id_participation
AND p.trash <> 1
WHERE prep.id_question IN (780,787,794,801,809)
AND prep.trash <> 1
GROUP BY pp.id_campaign
Explain of the query
And the problem is that this request is very heavy to execute when there is a lot of data which is concerned by the request and I do not know how to optimize it.
This query take 30-50ms to execute.
Structure of table participation :
CREATE TABLE IF NOT EXISTS `participation` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`id_campagne` int(11) NOT NULL,
`id_identifiant` int(11) DEFAULT NULL,
`firstname` varchar(255) DEFAULT NULL,
`surname` varchar(255) DEFAULT NULL,
`email` varchar(255) DEFAULT NULL,
`date_p` date NOT NULL,
`hour_p` time NOT NULL,
`comment` text,
`trash` tinyint(1) DEFAULT '0',
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Structure of table participation_rep :
CREATE TABLE IF NOT EXISTS `participation_rep` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`id_participation` int(11) NOT NULL,
`id_question` int(11) NOT NULL,
`id_rep` int(11) NOT NULL,
`trash` tinyint(1) DEFAULT '0',
PRIMARY KEY (`id`),
UNIQUE KEY `id_participation` (`id_participation`,`id_question`,`id_reponse`),
KEY `id_question` (`id_question`) USING BTREE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

MySQL - Any addtional indexes would speed up this query?

I see that my query does full table scan and takes a lot of time. I heard that making indexes would speed this up and I have added some to the tables. Is there any other indexes I should create to make this query faster?
My query is:
SELECT p.id, n.people_type_id, n.full_name, n.post, p.nick,
p.key_name, p.email, p.internal_user_id FROM email_routing e
JOIN people_emails p ON p.id=e.receiver_email_id
JOIN people n ON n.id = p.people_id
WHERE e.message_id = 897360 AND e.basket=1
Here is the EXPLAIN result:
EXPLAIN SELECT p.id, n.people_type_id, n.full_name, n.post, p.nick,
p.key_name, p.email, p.internal_user_id FROM email_routing e
JOIN people_emails p ON p.id=e.receiver_email_id
JOIN people n ON n.id = p.people_id
WHERE e.message_id = 897360 AND e.basket=1
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE n NULL ALL PRIMARY NULL NULL NULL 1 100.00 NULL
1 SIMPLE p NULL ALL PRIMARY NULL NULL NULL 3178 10.00 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE e NULL ref bk1 bk1 4 server.p.id 440 1.00 Using where; Using
And here are the tables strucutre:
SHOW CREATE TABLE people_emails;
CREATE TABLE `people_emails` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`nick` varchar(255) NOT NULL,
`email` varchar(255) NOT NULL,
`key_name` varchar(255) NOT NULL,
`people_id` int(11) NOT NULL,
`status` int(11) NOT NULL DEFAULT '0',
`activity` int(11) NOT NULL,
`internal_user_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
FULLTEXT KEY `email` (`email`)
) ENGINE=MyISAM AUTO_INCREMENT=22114 DEFAULT CHARSET=utf8
SHOW CREATE TABLE email_routing;
CREATE TABLE `email_routing` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`message_id` int(11) NOT NULL,
`sender_email_id` int(11) NOT NULL,
`receiver_email_id` int(11) NOT NULL,
`basket` int(11) NOT NULL,
`status` int(11) NOT NULL,
`popup` int(11) NOT NULL DEFAULT '0',
`tm` int(11) NOT NULL DEFAULT '0',
KEY `id` (`id`),
KEY `bk1` (`receiver_email_id`,`status`,`sender_email_id`,`message_id`,`basket`),
KEY `bk2` (`sender_email_id`,`tm`)
) ENGINE=InnoDB AUTO_INCREMENT=1054618 DEFAULT CHARSET=utf8
SHOW CREATE TABLE people;
CREATE TABLE `people` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`fname` varchar(255) CHARACTER SET cp1251 NOT NULL,
`lname` varchar(255) CHARACTER SET cp1251 NOT NULL,
`patronymic` varchar(255) CHARACTER SET cp1251 NOT NULL,
`gender` tinyint(1) NOT NULL,
`full_name` varchar(255) NOT NULL DEFAULT ' ',
`category` int(11) NOT NULL,
`people_type_id` int(255) DEFAULT NULL,
`tags` varchar(255) CHARACTER SET cp1251 NOT NULL,
`job` varchar(255) CHARACTER SET cp1251 NOT NULL,
`post` varchar(255) CHARACTER SET cp1251 NOT NULL,
`profession` varchar(255) CHARACTER SET cp1251 DEFAULT NULL,
`zip` varchar(16) CHARACTER SET cp1251 NOT NULL,
`country` int(11) DEFAULT NULL,
`region` varchar(10) NOT NULL,
`city` varchar(255) CHARACTER SET cp1251 NOT NULL,
`address` varchar(255) CHARACTER SET cp1251 NOT NULL,
`address_date` date DEFAULT NULL,
`inner` tinyint(4) NOT NULL,
`contact_through` varchar(255) DEFAULT '',
`next_call` date NOT NULL,
`additional` text CHARACTER SET cp1251 NOT NULL,
`user_id` int(11) NOT NULL,
`changed` datetime NOT NULL,
`status` int(11) DEFAULT NULL,
`nick` varchar(255) DEFAULT NULL,
`birthday` date DEFAULT NULL,
`last_update_ts` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`area` text NOT NULL,
`reviewed_` tinyint(4) NOT NULL,
`phones_old` text NOT NULL,
`post_sticker` text NOT NULL,
`permissions` int(120) NOT NULL DEFAULT '0',
`internal_user_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `most_used` (`category`,`status`,`city`,`lname`,`next_call`),
KEY `registrars` (`category`,`status`,`contact_through`,`next_call`),
FULLTEXT KEY `lname` (`lname`),
FULLTEXT KEY `fname` (`fname`),
FULLTEXT KEY `mname` (`patronymic`),
FULLTEXT KEY `Full Name` (`full_name`)
) ENGINE=MyISAM AUTO_INCREMENT=415009 DEFAULT CHARSET=utf8
How to choose columns for building indexes, should I pick text columnts too or that only will work with numer columnts
The table email_routing seem to have 1054618 rows .
And you try to find one row , by message_id .
e.message_id = 897360
BUT message_id must be indexed to speed-up the query .
message_id is part of the index bk1 , but this is not enough because message_id is not the first columns of the index .
email_routing needs
INDEX ( message_id, basket, -- first, in either order
receiver_email_id ) -- for "covering"
Your bk1 starts with receiver_email_id; this is not nearly as good.
Include column(s) in WHERE that are tested with =.
Include other columns from WHERE, GROUP BY, and ORDER BY (none in your case); the order is important, but beyond the scope of this discussion.
Include any other columns of the same table used anywhere in the query -- this is to make it a "covering" index. But don't bother if this would lead to more than, say, 5 columns or would involve TEXT, which cannot be in an index.
Then move on to the other tables. In both JOINs, it seems that they would be hit by their PRIMARY KEYs (JOIN x ON x.id = ...)
More discussion: Cookbook for creating indexes
On other issues...
You really should move to InnoDB. As of 5.6, it includes FULLTEXT, but there are some differences. In particular, you may need more fulltext indexes. For example, MATCH(lname, fname) requires FULLTEXT(lname, fname).
Do you really want to stick to cp1251? It limits your internalization mostly to English, Russian, Bulgarian, Serbian and Macedonian. And it is unclear how well FULLTEXT (MyISAM or InnoDB) will work with those non-English languages.
INTs are always 4 bytes; consider using smaller versions.
Is there really only one people? The Optimizer decided that was the best table to start with, but it wasn't. I'm hoping my improved index on email_routing will trick it into starting with that table -- which will definitely be optimal.

MySQL use separate indices for JOIN and GROUP BY

I am trying to execute following query
SELECT
a.sessionID AS `sessionID`,
firstSeen, birthday, gender,
isAnonymous, LanguageCode
FROM transactions AS trx
INNER JOIN actions AS a ON a.sessionID = trx.SessionID
WHERE a.ActionType = 'PURCHASE'
GROUP BY trx.TransactionNumber
Explain provides the following output
1 SIMPLE trx ALL TransactionNumber,SessionID NULL NULL NULL 225036 Using temporary; Using filesort
1 SIMPLE a ref sessionID sessionID 98 infinitiExport.trx.SessionID 1 Using index
The problem is that I am trying to use one field for join and different field for GROUP BY.
How can I tell MySQL to use different indices for same table?
CREATE TABLE `transactions` (
`SessionID` varchar(32) NOT NULL DEFAULT '',
`date` datetime DEFAULT NULL,
`TransactionNumber` varchar(32) NOT NULL DEFAULT '',
`CustomerECommerceTrackID` int(11) DEFAULT NULL,
`SKU` varchar(45) DEFAULT NULL,
`AmountPaid` double DEFAULT NULL,
`Currency` varchar(10) DEFAULT NULL,
`Quantity` int(11) DEFAULT NULL,
`Name` tinytext NOT NULL,
`Category` varchar(45) NOT NULL DEFAULT '',
`customerInfoXML` text,
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`id`),
KEY `TransactionNumber` (`TransactionNumber`),
KEY `SessionID` (`SessionID`)
) ENGINE=InnoDB AUTO_INCREMENT=212007 DEFAULT CHARSET=utf8;
CREATE TABLE `actions` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`sessionActionDate` datetime DEFAULT NULL,
`actionURL` varchar(255) DEFAULT NULL,
`sessionID` varchar(32) NOT NULL DEFAULT '',
`ActionType` varchar(64) DEFAULT NULL,
`CustomerID` int(11) DEFAULT NULL,
`IPAddressID` int(11) DEFAULT NULL,
`CustomerDeviceID` int(11) DEFAULT NULL,
`customerInfoXML` text,
PRIMARY KEY (`id`),
KEY `ActionType` (`ActionType`),
KEY `CustomerDeviceID` (`CustomerDeviceID`),
KEY `sessionID` (`sessionID`)
) ENGINE=InnoDB AUTO_INCREMENT=15042833 DEFAULT CHARSET=utf8;
Thanks
EDIT 1: My indexes were broken, I had to add (SessionID, TransactionNumber) index to transactions table, however now, when I try to include trx.customerInfoXML table mysql stops using index
EDIT 2 Another answer does not really solved my problem because it's not standard sql syntax and generally not a good idea to force indices.
For ORM users such syntax is a unattainable luxury.
EDIT 3 I updated my indices and it solved the problem, see EDIT 1

MySQL Sorting bad performance

I see the following (simplified) query appearing in my slow-log mysql file, it's by a search engine crawler that crawls all pages from a paginated website.
select * from listing
where
active=1
and approved=1
and deleted=0
and enabled=1
order by
full_listing desc,
picture_count*rating/rating_count desc,
rating desc
limit 21230, 10;
I'm surprised it takes over 8 seconds to process on a table of only 60,000 records.
The explain plan looks like this
1 SIMPLE listing0_ index_merge listing_active,listing_approved,listing_enabled,listing_deleted,sort_index listing_active,listing_approved,listing_enabled,listing_deleted 1,1,1,1 3102 Using intersect(listing_active,listing_approved,listing_enabled,listing_deleted); Using where; Using filesort
What index can I create in order to improve its performance?
table structure:
'CREATE TABLE `listing` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`account_id` bigint(20) DEFAULT NULL,
`domain_id` bigint(20) DEFAULT NULL,
`active` bit(1) NOT NULL,
`approved` bit(1) NOT NULL,
`denied` bit(1) NOT NULL,
`deleted` bit(1) NOT NULL,
`enabled` bit(1) NOT NULL,
`full_listing` bit(1) DEFAULT b''0'',
`public_id` varchar(255) DEFAULT NULL,
`name` varchar(100) NOT NULL,
`rating` int(11) NOT NULL,
`rating_count` int(11) NOT NULL,
`rating_enabled` bit(1) NOT NULL,
`picture_count` int(11) DEFAULT ''0'',
`createdAt` datetime NOT NULL,
`createdBy` varchar(15) NOT NULL,
`updatedAt` datetime NOT NULL,
`updatedBy` varchar(15) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `listing_public_id` (`public_id`),
KEY `FKB4DC521D9306A80C` (`account_id`),
KEY `FKB4DC522D7A66E1A8` (`domain_id`),
KEY `listing_active` (`active`),
KEY `listing_approved` (`approved`),
KEY `listing_enabled` (`enabled`),
KEY `listing_deleted` (`deleted`),
KEY `listing_picture_count` (`picture_count`),
KEY `listing_rating` (`rating`),
KEY `listing_rating_count` (`rating_count`),
KEY `listing_full_listing` (`full_listing`),
CONSTRAINT `listing_ibfk_1` FOREIGN KEY (`account_id`) REFERENCES `account` (`id`),
CONSTRAINT `listing_ibfk_2` FOREIGN KEY (`domain_id`) REFERENCES `domain` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=59512 DEFAULT CHARSET=utf8'
Using filesort could be a cause. What are the index's ? Personally i would use bitshifts for what you are doing for for example column status contains an int
with the right hand bits as this
0000
Active | Approved | Deleted | enabled
so in your example I would have where status = 1011
or status = 11 (when the bits are converted back in to ints)
Then you only have 1 index with all combinations (using 0 and 1 can sometimes make mysql ignore the index)