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When i try to update my torrents table (My torrent site permits to share only open source stuff) with the following query
UPDATE `torrents` SET `leech` = '0', `seed` = '1' WHERE `id` = '26784'
It take approximaty 0.5 seconds to update a table which contains only 20,000 records . My other queries are executed in less than 0.0478s (SELECT queries)
CREATE TABLE IF NOT EXISTS `torrents` (
`id` int(11) NOT NULL,
`hash_info` varchar(255) NOT NULL,
`category_slug` varchar(255) NOT NULL,
`name` varchar(255) NOT NULL,
`size` bigint(20) NOT NULL,
`age` int(11) NOT NULL,
`description` text NOT NULL,
`trackers` longtext NOT NULL,
`magnet` longtext,
`files` longtext,
`parent_category` int(11) NOT NULL,
`category` int(11) NOT NULL,
`publish_date` int(11) DEFAULT NULL,
`uploader` int(11) NOT NULL,
`seed` int(11) DEFAULT '0',
`leech` int(11) DEFAULT '0',
`file_key` varchar(255) DEFAULT NULL,
`comments_count` int(11) DEFAULT '0'
) ENGINE=InnoDB AUTO_INCREMENT=26816 DEFAULT CHARSET=latin1;
Any solution ?
Lookups based on the indexed columns are much faster than the lookups on the non-indexed columns. This behavior can be case more visible with the growing amount of the data.
Create an index on Id column and check if it helps you improve the performance of the query.
id is declared to be an integer. So, first your comparison should be to an integer not a string:
UPDATE `torrents`
SET `leech` = '0', `seed` = '1'
WHERE `id` = 26784;
Second, you need an index on the id. You can create one by:
create index idx_torrents_id on torrents(id);
Alternatively, make it a primary key in the table.
this is my simple inner join:
SELECT
SUM(ASSNZ.assenzeDidattiche) AS TotaleAssenze,
SUM(ASSNZ.ore) AS totale_parziale,
FLOOR(((SUM(ASSNZ.assenzeDidattiche) / SUM(ASSNZ.ore)) * 100)) AS andamento,
MAX(ASSNZ.dataLezione) AS ultima_lezione,
ASSNZ.idServizio,
ASSNZ.idUtente
FROM
ciac_corsi_assenze AS ASSNZ
INNER JOIN
ciac_serviziAcquistati_ITA AS ACQ
ON ACQ.idContatto = ASSNZ.idUtente
AND ACQ.idServizio = ASSNZ.idServizio
AND ACQ.stato_allievo <> 'ritirato'
GROUP BY
ASSNZ.idServizio,
ASSNZ.idUtente
table "ASSNZ" has 213886 rows with index "idUtente", "idServizio"
table "ACQ" has 8950 rows with index "idContatto", "idServizio"
ASSNZ table:
CREATE TABLE `ciac_corsi_assenze` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`idUtente` int(11) DEFAULT NULL,
`idServizio` int(11) DEFAULT NULL,
`idCorso` int(11) DEFAULT NULL,
`idCalendario` int(11) DEFAULT NULL,
`modalita` varchar(255) DEFAULT NULL,
`ore` int(11) DEFAULT NULL,
`assenzeDidattiche` float DEFAULT NULL,
`assenzeAmministrative` float DEFAULT NULL,
`dataLezione` date DEFAULT NULL,
`ora_inizio` varchar(8) DEFAULT NULL,
`ora_fine` varchar(8) DEFAULT NULL,
`dataFineStage` date DEFAULT NULL,
`giustificata` varchar(128) DEFAULT NULL,
`motivazione` longtext,
`grouped` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `idUtente` (`idUtente`) USING BTREE,
KEY `idServizio` (`idServizio`) USING BTREE,
KEY `dataLezione` (`dataLezione`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=574582 DEFAULT CHARSET=utf8;
ACQ table:
CREATE TABLE `ciac_serviziacquistati_ita` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`idServizio` int(11) NOT NULL,
`idContatto` int(11) NOT NULL,
`idAzienda` int(11) NOT NULL,
`idSede` int(11) NOT NULL,
`tipoPersona` int(11) NOT NULL,
`num_registro` int(11) NOT NULL,
`codice` varchar(255) CHARACTER SET latin1 DEFAULT NULL,
`dal` date NOT NULL,
`al` date NOT NULL,
`ore` int(11) NOT NULL,
`costoOrario` decimal(10,0) NOT NULL,
`annoFormativo` varchar(128) CHARACTER SET latin1 NOT NULL,
`stato_attuale` int(11) NOT NULL,
`datore_attuale` int(11) NOT NULL,
`stato_allievo` varchar(64) CHARACTER SET latin1 NOT NULL DEFAULT 'corsista',
`data_ritiro` date DEFAULT NULL,
`crediti_formativi` int(11) NOT NULL,
`note` longtext CHARACTER SET latin1 NOT NULL,
`valore_economico` decimal(10,2) NOT NULL,
`dataInserimento` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
KEY `idServizio` (`idServizio`) USING BTREE,
KEY `idAzienda` (`idAzienda`) USING BTREE,
KEY `idContatto` (`idContatto`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=9542 DEFAULT CHARSET=utf8;
this is my EXPLAIN of the select
Now because the query is slow, during 1.5s / 2.0s??
Something wrong?
UPDATE
added new index (with the John Bollinger's answer) to the table ciac_corsi_assenze:
PRIMARY KEY (`id`),
KEY `dataLezione` (`dataLezione`) USING BTREE,
KEY `test` (`idUtente`,`idServizio`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=574582 DEFAULT CHARSET=utf8;
added new index to the table ciac_serviziAcquistati_ITA:
PRIMARY KEY (`id`),
KEY `idAzienda` (`idAzienda`) USING BTREE,
KEY `test2` (`idContatto`,`idServizio`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=9542 DEFAULT CHARSET=utf8;
New EXPLAIN:
But it's always slow :(
Your tables have separate indexes on various columns of interest, but MySQL will use at most one index per table to perform your query. This particular query would probably be sped by table ciac_corsi_assenze having an index on (idUtente, idServizio) (and such an index would supersede the existing one on (idUtente) alone). That should allow MySQL to avoid sorting the result rows to perform the grouping, and it will help more in performing the join than any of the existing indexes do.
The query would probably be sped further by table ciac_serviziAcquistati_ITA having an index on (idContatto, idServizio), or even on (idContatto, idServizio, ritirato). Either of those would supersede the existing index on just (idContatto).
John went the right direction. However the order of columns in the composite index needs changing.
For the GROUP BY, this order is needed (on ASSNZ):
INDEX(idServizio, idUtente)
(and that should replace KEY(idServizio), but not KEY(idUtente))
Then ACQ needs, in this order:
INDEX(idContatto, idServizio, stato_allievo)
replacing only KEY(idContatto).
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
i have such 3 tables. Im trying to Left Join them
SELECT `t`.`title` AS `category_title`,`t`.`id` AS `category_id`, `st`.`title` AS
`subcategory_title`, `st`.`id` AS `subcategory_id`, `st`.`parent_id` AS
`subcategory_parent`, `n`.`title` AS `news_title`,`n`.`id` AS `news_id` FROM
`t_categories` `t` LEFT JOIN t_categories AS `st` ON `st`.`parent_id`=t.`id` LEFT JOIN
t_newsrelations AS `nr` ON `nr`.`category_id`=st.`id` LEFT JOIN t_news AS `n` ON
`n`.`id`=nr.`news_id` WHERE `t`.`enabled` = 1 AND `n`.`enabled` = 1 AND `n`.`type`!=1 AND
`n`.`type`!=5 ORDER BY `t`.`position`,`st`.`position`,`n`.`position` ASC
here is the structure of tables
CREATE TABLE IF NOT EXISTS `t_categories` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`parent_id` int(11) NOT NULL,
`title` tinytext NOT NULL,
`position` tinyint(4) unsigned NOT NULL DEFAULT '0',
`type` tinyint(1) unsigned NOT NULL,
`enabled` tinyint(1) unsigned NOT NULL DEFAULT '1',
UNIQUE KEY `id` (`id`),
KEY `type` (`type`),
KEY `parent_id` (`parent_id`),
KEY `enabled` (`enabled`),
KEY `id_parent_position_enabled` (`id`,`parent_id`,`position`,`enabled`),
KEY `position` (`position`),
KEY `parent_id_2` (`parent_id`,`enabled`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 ;
CREATE TABLE IF NOT EXISTS `t_news` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`title` tinytext NOT NULL,
`m_title` tinytext NOT NULL,
`url` varchar(2000) NOT NULL,
`keywords` text NOT NULL,
`description` text NOT NULL,
`body` longtext NOT NULL,
`position` tinyint(4) unsigned NOT NULL DEFAULT '0',
`type` tinyint(1) unsigned NOT NULL,
`city_id` int(4) NOT NULL,
`quickmenu_enabled` tinyint(1) unsigned NOT NULL DEFAULT '0',
`quickmenu` text NOT NULL,
`enabled` tinyint(1) unsigned NOT NULL DEFAULT '1',
PRIMARY KEY (`id`),
UNIQUE KEY `id` (`id`),
KEY `position` (`position`),
KEY `type` (`type`),
KEY `city_id` (`city_id`),
KEY `url` (`url`(333)),
KEY `quickmenu_enabled` (`quickmenu_enabled`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 ;
CREATE TABLE IF NOT EXISTS `t_newsrelations` (
`category_id` int(11) NOT NULL,
`news_id` int(11) unsigned NOT NULL,
KEY `category_id` (`category_id`),
KEY `news_id` (`news_id`),
KEY `category_id_2` (`category_id`,`news_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
And SELECT EXPLAIN shows me
t_newsrelations is intermediate table. Table t_categories contains categories and subcategories linked by parent_id column. Each item from t_news can be a member of more than one subcategories thats why they linked through t_newsrelations
how to optimise a query? Why it shows Using index, Using temporary, Using filesort?
ORDER BY `t`.`position`,`st`.`position`,`n`.`position` ASC
You can't eliminate the temp table and filesort in this query, given the tables you have, because you're sorting on columns from multiple tables. Optimizing sorting means using an index so that the query fetches rows in the order you want them. But there's no way in MySQL to create an index that spans multiple tables.
The only way to fix this is to denormalize until all three columns are in a single table, and create one index over the three columns. But denormalization comes with its own downsides.
Tables:
nodes
data_texts
data_profiles
data_locations
data_profiles
data_media
data_products
data_metas
categories
tags
categories_nodes
tags_nodes
This question is a generalized question and is on the back of another question
Explanation:
Each of the "data" tables has a node_id that refers back to the id of the nodes table (hasMany/belongsTo association).
A "Node" can be anything - a TV Show, a Movie, a Person, an Article...etc (all generated via a CMS, so the user can control what type of "Nodes" they want).
When pulling data, I want to be able to query against certain fields. For example if they do a search, I want to be able to pull nodes that have data_texts.title = '%george%' or order by the datetime field in data_locations.
The problem is, when I do a join on all seven data tables (or more), the query has to hit so many combined rows that it just times out (even with a nearly empty database.... total 200 rows across the entire database).
I realize I can determine IF I need a join depending on what I'm doing - but even with five or six joins (once the database gets to 10k+ records), it's going to be horribly slow, if it works at all. Per this question, the query I'm using just doing a join on these tables times out completely.
Each node can have multiple rows of each data type (for multi-language reasons among others).
I'm completely defeated - I'm at the point where I think I need to restructure the entire thing, but don't have the time for that. I've thought about combining all into one table, but aren't sure how....etc
nodes
CREATE TABLE `nodes` (
`id` CHAR(36) NOT NULL,
`name` VARCHAR(100) NOT NULL,
`slug` VARCHAR(100) NOT NULL,
`node_type_id` CHAR(36) NOT NULL,
`site_id` CHAR(36) NOT NULL,
`created` DATETIME NOT NULL,
`modified` DATETIME NOT NULL,
PRIMARY KEY (`id`),
INDEX `nodeTypeId` (`node_type_id`),
INDEX `slug` (`slug`),
INDEX `nodeId` (`id`)
)
COLLATE='latin1_swedish_ci'
ENGINE=MyISAM;
data_texts:
CREATE TABLE `data_texts` (
`id` CHAR(36) NOT NULL,
`title` VARCHAR(250) NULL DEFAULT NULL,
`subtitle` VARCHAR(500) NULL DEFAULT NULL,
`content` LONGTEXT NULL,
`byline` VARCHAR(250) NULL DEFAULT NULL,
`language_id` CHAR(36) NULL DEFAULT NULL,
`foreign_key` CHAR(36) NULL DEFAULT NULL,
`model` VARCHAR(40) NULL DEFAULT NULL,
`node_id` CHAR(36) NULL DEFAULT NULL,
`created` DATETIME NOT NULL,
`modified` DATETIME NOT NULL,
PRIMARY KEY (`id`),
INDEX `nodeId` (`node_id`),
INDEX `languageId_nodeId` (`language_id`, `node_id`),
INDEX `foreignKey_model` (`foreign_key`, `model`)
)
COLLATE='utf8_general_ci'
ENGINE=MyISAM;
data_profiles
CREATE TABLE `data_profiles` (
`id` CHAR(36) NOT NULL,
`name` VARCHAR(80) NULL DEFAULT NULL,
`email_personal` VARCHAR(100) NULL DEFAULT NULL,
`email_business` VARCHAR(100) NULL DEFAULT NULL,
`email_other` VARCHAR(100) NULL DEFAULT NULL,
`title` VARCHAR(100) NULL DEFAULT NULL,
`description` LONGTEXT NULL,
`prefix` VARCHAR(40) NULL DEFAULT NULL,
`phone_home` VARCHAR(40) NULL DEFAULT NULL,
`phone_business` VARCHAR(40) NULL DEFAULT NULL,
`phone_mobile` VARCHAR(40) NULL DEFAULT NULL,
`phone_other` VARCHAR(40) NULL DEFAULT NULL,
`foreign_key` CHAR(36) NULL DEFAULT NULL,
`model` VARCHAR(40) NULL DEFAULT NULL,
`node_id` CHAR(36) NULL DEFAULT NULL,
`language_id` CHAR(36) NULL DEFAULT NULL,
`created` DATETIME NOT NULL,
`modified` DATETIME NOT NULL,
`user_id` CHAR(36) NULL DEFAULT NULL,
PRIMARY KEY (`id`),
INDEX `nodeId` (`node_id`),
INDEX `languageId_nodeId` (`node_id`, `language_id`),
INDEX `foreignKey_model` (`foreign_key`, `model`)
)
COLLATE='latin1_swedish_ci'
ENGINE=MyISAM;
categories
CREATE TABLE `categories` (
`id` CHAR(36) NOT NULL,
`name` VARCHAR(100) NOT NULL,
`node_type_id` CHAR(36) NOT NULL,
`site_id` CHAR(36) NOT NULL,
`slug` VARCHAR(100) NOT NULL,
`created` DATETIME NOT NULL,
`modified` DATETIME NOT NULL,
PRIMARY KEY (`id`),
INDEX `nodeTypeId` (`node_type_id`),
INDEX `slug` (`slug`)
)
COMMENT='Used to categorize nodes'
COLLATE='utf8_general_ci'
ENGINE=MyISAM;
categories_nodes
CREATE TABLE `categories_nodes` (
`id` CHAR(36) NOT NULL,
`category_id` CHAR(36) NOT NULL,
`node_id` CHAR(36) NOT NULL,
PRIMARY KEY (`id`),
INDEX `categoryId_nodeId` (`category_id`, `node_id`)
)
COLLATE='utf8_general_ci'
ENGINE=MyISAM;
node_tags
CREATE TABLE `node_tags` (
`id` CHAR(36) NOT NULL,
`name` VARCHAR(40) NOT NULL,
`site_id` CHAR(36) NOT NULL,
`created` DATETIME NOT NULL,
`modified` DATETIME NOT NULL,
PRIMARY KEY (`id`),
INDEX `siteId` (`site_id`)
)
COLLATE='utf8_general_ci'
ENGINE=MyISAM;
nodes_node_tags
CREATE TABLE `nodes_node_tags` (
`id` CHAR(36) NOT NULL,
`node_id` CHAR(36) NOT NULL,
`node_tag_id` CHAR(36) NOT NULL,
PRIMARY KEY (`id`),
INDEX `node_id_node_tag_id` (`node_id`, `node_tag_id`)
)
COLLATE='utf8_general_ci'
ENGINE=MyISAM;
MySQL:
SELECT `Node`.`id`, `Node`.`name`, `Node`.`slug`, `Node`.`node_type_id`, `Node`.`site_id`, `Node`.`created`, `Node`.`modified`
FROM `mysite`.`nodes` AS `Node`
LEFT JOIN `mysite`.`data_date_times` AS `DataDateTime` ON (`DataDateTime`.`node_id` = `Node`.`id`)
LEFT JOIN `mysite`.`data_locations` AS `DataLocation` ON (`DataLocation`.`node_id` = `Node`.`id`)
LEFT JOIN `mysite`.`data_media` AS `DataMedia` ON (`DataMedia`.`node_id` = `Node`.`id`)
LEFT JOIN `mysite`.`data_metas` AS `DataMeta` ON (`DataMeta`.`node_id` = `Node`.`id`)
LEFT JOIN `mysite`.`data_profiles` AS `DataProfile` ON (`DataProfile`.`node_id` = `Node`.`id`)
LEFT JOIN `mysite`.`data_products` AS `DataProduct` ON (`DataProduct`.`node_id` = `Node`.`id`)
LEFT JOIN `mysite`.`data_texts` AS `DataText` ON (`DataText`.`node_id` = `Node`.`id`)
WHERE 1=1
GROUP BY `Node`.`id`
Firstly, try InnoDB, not MyISAM.
Secondly, remove the group by, see how well it runs then, and how many rows are involved. Shouldn't be that many, but it's interesting.
You don't need the 'nodeId' index on node (as you already have it as a primary key). Again, shouldn't make any difference.
The where clause is irrelevant. You can remove it with no effect one way or another.
Thirdly, well, something is seriously broken.
Have a quick look on how to start profiling (e.g. http://dev.mysql.com/doc/refman/5.0/en/show-profile.html) , and run a profile command to see where all the time is going. Post it here if it doesn't immediately show that something is broken.
I'm unfortunately not in a position where I can do any tests right now. I'll just throw out some ideas. I might be able to do some tests later.
Be suspicious of different collations.
Some of your ids are useless. For example, you should drop the column categories_nodes.id, and put a primary key constraint on {category_id, node_id} instead.
Be suspicious of any design that requires joining all the tables at run time. There are better ways.
Use innodb and foreign key constraints.