mysql - MariaDB/PostgreSQL - 查询优化

Question

我需要产生一些数字，我设计了一个查询来获得我的“客户”想要的结果。该查询基于包含一百万条记录的表。我通常使用 MariaDB，大约 7 秒内就能得到结果。这个执行时间非常合适，但我希望再次优化以提高我的技能。经过一番研究，我发现一些帖子说“MySQL 很好，但不适用于> 1M 记录的表，你必须打开其他东西” PostgreSQL 已被多次引用。所以我安装了 PostgreSQL，并复制了我的表、索引和数据。我执行了相同的查询，大约 12 秒内就得到了结果

我对 PostgreSQL 了解较少，我认为我没有使用该语言固有的特殊性。所以现在我仍然使用 MariaDB。您有改善执行时间的想法吗？

这是我的查询:

select categorie.cat
,dhu_type.type
,COUNT(DISTINCT(
    CASE WHEN dhu.date between '2013-01-01' and '2013-12-31'    
    THEN dhu.id
    END )

  ) AS "2013"
,COUNT(DISTINCT(
    CASE WHEN dhu.date between '2014-01-01' and '2014-12-31'    
    THEN dhu.id
    END )

  ) AS "2014"
,COUNT(DISTINCT(
    CASE WHEN dhu.date between '2015-01-01' and '2015-12-31'     
    THEN dhu.id
    END )

  ) AS "2015"
,COUNT(DISTINCT(
    CASE WHEN dhu.date between '2016-01-01' and '2016-12-31'       
    THEN dhu.id
    END )

  ) AS "2016"
from dhu
inner join dhu_type on dhu.type_id = dhu_type.id
inner join patient on dhu.patient_id=patient.id
inner join fa on patient.id = fa.patient_id
inner join categorie on categorie.id = fa.cat_id
group by cat,dhu_type.type

我用图表来完成我的问题

这里创建表:

/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET NAMES utf8 */;
/*!50503 SET NAMES utf8mb4 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;


CREATE TABLE IF NOT EXISTS `categorie` (
  `id` tinyint(3) unsigned NOT NULL AUTO_INCREMENT,
  `cat` varchar(50) NOT NULL DEFAULT 'neonat',
  PRIMARY KEY (`id`,`cat`)
) ENGINE=InnoDB AUTO_INCREMENT=16 DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS `cp` (
  `id` smallint(5) unsigned NOT NULL AUTO_INCREMENT,
  `cp` varchar(5) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `cp` (`cp`)
) ENGINE=InnoDB AUTO_INCREMENT=4096 DEFAULT CHARSET=utf8;


CREATE TABLE IF NOT EXISTS `dhu` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `patient_id` int(10) unsigned NOT NULL,
  `date` date NOT NULL,
  `type_id` tinyint(3) unsigned NOT NULL,
  PRIMARY KEY (`id`),
  KEY `FK_dhu_patient` (`patient_id`),
  KEY `FK_dhu_dhu_type` (`type_id`),
  CONSTRAINT `FK_dhu_dhu_type` FOREIGN KEY (`type_id`) REFERENCES `dhu_type` (`id`),
  CONSTRAINT `FK_dhu_patient` FOREIGN KEY (`patient_id`) REFERENCES `patient` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=953590 DEFAULT CHARSET=utf8;


CREATE TABLE IF NOT EXISTS `dhu_import` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `noip` bigint(10) unsigned zerofill NOT NULL,
  `date` date NOT NULL,
  `cp` varchar(5) NOT NULL,
  `type` varchar(4) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `noip` (`noip`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS `dhu_type` (
  `id` tinyint(3) unsigned NOT NULL AUTO_INCREMENT,
  `type` varchar(4) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `type` (`type`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS `dpt` (
  `dpt` tinyint(3) unsigned DEFAULT NULL,
  `abrev` char(3) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;


CREATE TABLE IF NOT EXISTS `fa` (
  `patient_id` int(10) unsigned NOT NULL,
  `cat_id` tinyint(3) unsigned NOT NULL,
  PRIMARY KEY (`patient_id`,`cat_id`),
  KEY `idx_cat_id_pat_id` (`cat_id`,`patient_id`),
  CONSTRAINT `FK_fa_patient` FOREIGN KEY (`patient_id`) REFERENCES `patient` (`id`),
  CONSTRAINT `FK_fa_categorie` FOREIGN KEY (`cat_id`) REFERENCES `categorie` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;


CREATE TABLE IF NOT EXISTS `fa_import` (
  `noip` bigint(10) unsigned zerofill NOT NULL,
  `cat` varchar(50) NOT NULL,
  PRIMARY KEY (`noip`,`cat`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=COMPACT;

CREATE TABLE IF NOT EXISTS `patient` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `noip` bigint(10) unsigned zerofill NOT NULL,
  `cp_id` smallint(5) unsigned NOT NULL,
  PRIMARY KEY (`id`),
  KEY `FK_patient_cp` (`cp_id`),
  CONSTRAINT `FK_patient_cp` FOREIGN KEY (`cp_id`) REFERENCES `cp` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=262141 DEFAULT CHARSET=utf8;


/*!40101 SET SQL_MODE=IFNULL(@OLD_SQL_MODE, '') */;
/*!40014 SET FOREIGN_KEY_CHECKS=IF(@OLD_FOREIGN_KEY_CHECKS IS NULL, 1, @OLD_FOREIGN_KEY_CHECKS) */;
/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;

这里解释查询:

这里进行了改进性能的修改(选择categorie.id而不是categorie.cat):

这是我找到的最好的查询，感谢@RickJames 和@BillKarwin

select categorie.cat
,dhu_type.`type`
,t.`2013`
,t.`2014`
,t.`2015`
,t.`2016` 
from ( select fa.cat_id as catid
,dhu.type_id typid
,COUNT(DISTINCT(
    CASE WHEN dhu.date between '2013-01-01' and '2013-12-31'    
    THEN dhu.id
    END )

  ) AS "2013"
,COUNT(DISTINCT(
    CASE WHEN dhu.date between '2014-01-01' and '2014-12-31'    
    THEN dhu.id
    END )

  ) AS "2014"
,COUNT(DISTINCT(
    CASE WHEN dhu.date between '2015-01-01' and '2015-12-31'     
    THEN dhu.id
    END )

  ) AS "2015"
,COUNT(DISTINCT(
    CASE WHEN dhu.date between '2016-01-01' and '2016-12-31'       
    THEN dhu.id
    END )

  ) AS "2016"
from dhu
inner join patient on dhu.patient_id=patient.id
inner join fa on patient.id = fa.patient_id
group by fa.cat_id, dhu.type_id ) t

inner join categorie on t.catid = categorie.id
inner join dhu_type on t.typid = dhu_type.id

order by categorie.cat,dhu_type.`type`

Answer 1

• MySQL 可以很好地处理十亿行的表。

• 任何数据库引擎都受到磁盘速度和用于缓存的 RAM 的大小的影响。

• 教科书说要规范化所有内容，但我建议 4 字符 type 不值得规范化。 5 字符 cp 也是如此。

• 除非您确实希望输出行全部为零，否则请在 之前添加此 WHERE dhu.date between '2016-01-01' 和 '2016-12-31'分组依据。

• 听从我的建议 here关于多:多模式设计 (fa)。这可能会加快 MySQL 的查询速度。 (我不知道同样的原则是否适用于 Postgres。)