MySQL普通表如何转换成分区表
目录
- 版本:
- 前言:
- 改造分区前期条件:
- 分区改造案例:
- 总结
版本:
MySQL-5.7.32
前言:
对于业务繁忙的数据库来说，在运行了一定时间后，往往会产生一些数据量较大的表，特别是对于每天新增数据较多的日志表或者流水表，大表对于日常的运维非常的不方便，特别是数据的清理、迁移，表的访问性能也会随着数据量的增大而受到影响，因此，对于大表我们需要进行优化拆分，通常拆分的方案有
所以，通常选择分区表改造方案的主要原因都是为了避免应用层面的改造，对应用层面透明，以及方便日常的运维，前提是表具备改造分区条件。
改造分区前期条件:
参考文档
1 根据业务的场景以及数据的分布，确认是否有匹配的分区表类型以及分区列
- 对于日志表，流水表这种按日期类型进行操作的，可以选择进行range分区
- 对于按用户ID类型的进行操作的，可以选择进行hash，key分区
- 对于按渠道，类型的进行操作的，可以选择进行list分区
2 应用涉及的sql，需要90%以上的操作都包含分区列，按分区操作，如果sql没有包含分区条件，扫描全分区，性能会出现下降。
查询表sql操作历史
select db,query,exec_count from sys.x$statement_analysis where lower(query) like '%%'order by exec_count;
3 主键必须包含分区键
4 分区键表达式只支持部分函数，存储过程，不支持二级制操作符以及/
5 分区不支持外键
查询表外键
select * from information_schema.KEY_COLUMN_USAGE where constraint_schema ='' and REFERENCED_TABLE_SCHEMA is not null\G
6 不支持查询缓存
7 5.7版本单个表分区最大支持8192个，并且会话第一次访问分区表，都需要打开全部的分区表，所以避免建立过多的分区
8 数据库最大文件打开数open_files_limit要设置足够大以满足表，分区的打开数量
9 数据库大文件large_files_support设置为on
10 分区列支持null值(对于rang分区，null值总小于任何的一个非null值，即存放在最左边的分区;对于list分区需要显示指定null值条件)，但从数据管理以及规范来看，不建议分区列存放null值，并且如果表有主键，则分区列不能为null值，因为分区列需要作为主键的一部分，不能为null
12 MySQL目前没有自动分区功能，所以需要监控分区的使用情况，通过job自动或者定时手动添加新分区
13 确定数据保留期限，定期归档分区数据
分区改造案例:
以下是一张数据量为766万的大表xxxx_user. xxxx_tab,计划将其改造为范围分区，按月存放。
select table_schema,table_name,table_rows,data_length/1024/1024/1024 from information_schema.tables where table_name='xxxx_tab';
表结构
CREATE TABLE `xxxx_tab` ( `ROLE_SEQ` bigint(20) NOT NULL , `PRD_ID` varchar(64) NOT NULL , `MAKE_RIGHT` varchar(1) DEFAULT '0' , `CHECK_RIGHT` varchar(1) DEFAULT '0' , `AUTH_RIGHT` varchar(1) DEFAULT '0' , `AUTH_GROUP` varchar(4) DEFAULT NULL , `RELEASE_RIGHT` varchar(1) DEFAULT '0' , `CREATE_USER_SEQ` bigint(20) DEFAULT NULL , `CREATE_DEPT_SEQ` bigint(20) DEFAULT NULL , `CREATE_TIME` datetime DEFAULT NULL , `UPDATE_USER_SEQ` bigint(20) DEFAULT NULL , `UPDATE_DEPT_SEQ` bigint(20) DEFAULT NULL , `UPDATE_TIME` datetime DEFAULT NULL , PRIMARY KEY (`PRD_ID`,`ROLE_SEQ`), KEY `xxxx_tab_IDX01` (`ROLE_SEQ`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
分区列create_time日期最大值，最小值，根据这个范围按月创建分区
select max(CREATE_TIME),min(CREATE_TIME) from xxxx_tab;
分区列null值，对于存在的null值，需要应用对null数据进行处理，并且程序上需要确保数据写入not null
select count(*) from xxxx_tab where create_time is null;
主键重建添加分区列
alter table xxxx_tab drop primary key,add primary key (`PRD_ID`,`ROLE_SEQ`,`CREATE_TIME`);
由于主键没有包含分区列，需要重建主键添加分区列，对于主键重建我采取的是官方的online ddl功能，这种ddl操作会造成主从延时，但是不会产生大量的binlog，对于主从实时性要求高的，可以采用第三方的在线工具pt-osc,gh-ost
表转化为分区表
采用pt-osc在线将表转化为分区表，对于partition by 官方是不支持online ddl的，所以需要采用第三方的在线工具
./pt-online-schema-change --user=xxx --password=xxx --charset=utf8 D=xxxx_user,t=xxxx_tab --alter "PARTITION BY RANGE COLUMNS(CREATE_TIME)
(PARTITION p200001 VALUES LESS THAN ('2000-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p200101 VALUES LESS THAN ('2001-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p201707 VALUES LESS THAN ('2017-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p201708 VALUES LESS THAN ('2017-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p201709 VALUES LESS THAN ('2017-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p201710 VALUES LESS THAN ('2017-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p201711 VALUES LESS THAN ('2017-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p201712 VALUES LESS THAN ('2018-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p201801 VALUES LESS THAN ('2018-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p201802 VALUES LESS THAN ('2018-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p201803 VALUES LESS THAN ('2018-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p201804 VALUES LESS THAN ('2018-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p201805 VALUES LESS THAN ('2018-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p201806 VALUES LESS THAN ('2018-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p201807 VALUES LESS THAN ('2018-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p201808 VALUES LESS THAN ('2018-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p201809 VALUES LESS THAN ('2018-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p201810 VALUES LESS THAN ('2018-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p201811 VALUES LESS THAN ('2018-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p201812 VALUES LESS THAN ('2019-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p201901 VALUES LESS THAN ('2019-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p201902 VALUES LESS THAN ('2019-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p201903 VALUES LESS THAN ('2019-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p201904 VALUES LESS THAN ('2019-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p201905 VALUES LESS THAN ('2019-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p201906 VALUES LESS THAN ('2019-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p201907 VALUES LESS THAN ('2019-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p201908 VALUES LESS THAN ('2019-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p201909 VALUES LESS THAN ('2019-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p201910 VALUES LESS THAN ('2019-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p201911 VALUES LESS THAN ('2019-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p201912 VALUES LESS THAN ('2020-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p202001 VALUES LESS THAN ('2020-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p202002 VALUES LESS THAN ('2020-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p202003 VALUES LESS THAN ('2020-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p202004 VALUES LESS THAN ('2020-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p202005 VALUES LESS THAN ('2020-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p202006 VALUES LESS THAN ('2020-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p202007 VALUES LESS THAN ('2020-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p202008 VALUES LESS THAN ('2020-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p202009 VALUES LESS THAN ('2020-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p202010 VALUES LESS THAN ('2020-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p202011 VALUES LESS THAN ('2020-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p202012 VALUES LESS THAN ('2021-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p202101 VALUES LESS THAN ('2021-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p202102 VALUES LESS THAN ('2021-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p202103 VALUES LESS THAN ('2021-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p202104 VALUES LESS THAN ('2021-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p202105 VALUES LESS THAN ('2021-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p202106 VALUES LESS THAN ('2021-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p202107 VALUES LESS THAN ('2021-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p202108 VALUES LESS THAN ('2021-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p202109 VALUES LESS THAN ('2021-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p202110 VALUES LESS THAN ('2021-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p202111 VALUES LESS THAN ('2021-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p202112 VALUES LESS THAN ('2022-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p202201 VALUES LESS THAN ('2022-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p202202 VALUES LESS THAN ('2022-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p202203 VALUES LESS THAN ('2022-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p202204 VALUES LESS THAN ('2022-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p202205 VALUES LESS THAN ('2022-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p202206 VALUES LESS THAN ('2022-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p202207 VALUES LESS THAN ('2022-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p202208 VALUES LESS THAN ('2022-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p202209 VALUES LESS THAN ('2022-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p202210 VALUES LESS THAN ('2022-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p202211 VALUES LESS THAN ('2022-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p202212 VALUES LESS THAN ('2023-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p202301 VALUES LESS THAN ('2023-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p202302 VALUES LESS THAN ('2023-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p202303 VALUES LESS THAN ('2023-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p202304 VALUES LESS THAN ('2023-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p202305 VALUES LESS THAN ('2023-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p202306 VALUES LESS THAN ('2023-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p202307 VALUES LESS THAN ('2023-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p202308 VALUES LESS THAN ('2023-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p202309 VALUES LESS THAN ('2023-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p202310 VALUES LESS THAN ('2023-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p202311 VALUES LESS THAN ('2023-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p202312 VALUES LESS THAN ('2024-01-01 00:00:00') ENGINE = InnoDB,
PARTITION pmax VALUES LESS THAN (MAXVALUE) ENGINE = InnoDB)" --recursion-method hosts --max-lag 600 --nodrop-old-table --print --statistics --execute
分区后表模型
CREATE TABLE `xxxx_tab` (
`ROLE_SEQ` bigint(20) NOT NULL ,
`PRD_ID` varchar(64) NOT NULL ,
`MAKE_RIGHT` varchar(1) DEFAULT '0' ,
`CHECK_RIGHT` varchar(1) DEFAULT '0' ,
`AUTH_RIGHT` varchar(1) DEFAULT '0' ,
`AUTH_GROUP` varchar(4) DEFAULT NULL ,
`RELEASE_RIGHT` varchar(1) DEFAULT '0' ,
`CREATE_USER_SEQ` bigint(20) DEFAULT NULL ,
`CREATE_DEPT_SEQ` bigint(20) DEFAULT NULL ,
`CREATE_TIME` datetime NOT NULL ,
`UPDATE_USER_SEQ` bigint(20) DEFAULT NULL ,
`UPDATE_DEPT_SEQ` bigint(20) DEFAULT NULL ,
`UPDATE_TIME` datetime DEFAULT NULL ,
PRIMARY KEY (`PRD_ID`,`ROLE_SEQ`,`CREATE_TIME`),
KEY `xxxx_tab_IDX01` (`ROLE_SEQ`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4
PARTITION BY RANGE COLUMNS(CREATE_TIME)
(PARTITION p200001 VALUES LESS THAN ('2000-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p200101 VALUES LESS THAN ('2001-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p201707 VALUES LESS THAN ('2017-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p201708 VALUES LESS THAN ('2017-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p201709 VALUES LESS THAN ('2017-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p201710 VALUES LESS THAN ('2017-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p201711 VALUES LESS THAN ('2017-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p201712 VALUES LESS THAN ('2018-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p201801 VALUES LESS THAN ('2018-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p201802 VALUES LESS THAN ('2018-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p201803 VALUES LESS THAN ('2018-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p201804 VALUES LESS THAN ('2018-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p201805 VALUES LESS THAN ('2018-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p201806 VALUES LESS THAN ('2018-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p201807 VALUES LESS THAN ('2018-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p201808 VALUES LESS THAN ('2018-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p201809 VALUES LESS THAN ('2018-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p201810 VALUES LESS THAN ('2018-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p201811 VALUES LESS THAN ('2018-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p201812 VALUES LESS THAN ('2019-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p201901 VALUES LESS THAN ('2019-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p201902 VALUES LESS THAN ('2019-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p201903 VALUES LESS THAN ('2019-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p201904 VALUES LESS THAN ('2019-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p201905 VALUES LESS THAN ('2019-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p201906 VALUES LESS THAN ('2019-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p201907 VALUES LESS THAN ('2019-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p201908 VALUES LESS THAN ('2019-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p201909 VALUES LESS THAN ('2019-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p201910 VALUES LESS THAN ('2019-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p201911 VALUES LESS THAN ('2019-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p201912 VALUES LESS THAN ('2020-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p202001 VALUES LESS THAN ('2020-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p202002 VALUES LESS THAN ('2020-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p202003 VALUES LESS THAN ('2020-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p202004 VALUES LESS THAN ('2020-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p202005 VALUES LESS THAN ('2020-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p202006 VALUES LESS THAN ('2020-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p202007 VALUES LESS THAN ('2020-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p202008 VALUES LESS THAN ('2020-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p202009 VALUES LESS THAN ('2020-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p202010 VALUES LESS THAN ('2020-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p202011 VALUES LESS THAN ('2020-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p202012 VALUES LESS THAN ('2021-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p202101 VALUES LESS THAN ('2021-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p202102 VALUES LESS THAN ('2021-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p202103 VALUES LESS THAN ('2021-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p202104 VALUES LESS THAN ('2021-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p202105 VALUES LESS THAN ('2021-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p202106 VALUES LESS THAN ('2021-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p202107 VALUES LESS THAN ('2021-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p202108 VALUES LESS THAN ('2021-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p202109 VALUES LESS THAN ('2021-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p202110 VALUES LESS THAN ('2021-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p202111 VALUES LESS THAN ('2021-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p202112 VALUES LESS THAN ('2022-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p202201 VALUES LESS THAN ('2022-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p202202 VALUES LESS THAN ('2022-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p202203 VALUES LESS THAN ('2022-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p202204 VALUES LESS THAN ('2022-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p202205 VALUES LESS THAN ('2022-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p202206 VALUES LESS THAN ('2022-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p202207 VALUES LESS THAN ('2022-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p202208 VALUES LESS THAN ('2022-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p202209 VALUES LESS THAN ('2022-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p202210 VALUES LESS THAN ('2022-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p202211 VALUES LESS THAN ('2022-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p202212 VALUES LESS THAN ('2023-01-01 00:00:00') ENGINE = InnoDB,
PARTITION p202301 VALUES LESS THAN ('2023-02-01 00:00:00') ENGINE = InnoDB,
PARTITION p202302 VALUES LESS THAN ('2023-03-01 00:00:00') ENGINE = InnoDB,
PARTITION p202303 VALUES LESS THAN ('2023-04-01 00:00:00') ENGINE = InnoDB,
PARTITION p202304 VALUES LESS THAN ('2023-05-01 00:00:00') ENGINE = InnoDB,
PARTITION p202305 VALUES LESS THAN ('2023-06-01 00:00:00') ENGINE = InnoDB,
PARTITION p202306 VALUES LESS THAN ('2023-07-01 00:00:00') ENGINE = InnoDB,
PARTITION p202307 VALUES LESS THAN ('2023-08-01 00:00:00') ENGINE = InnoDB,
PARTITION p202308 VALUES LESS THAN ('2023-09-01 00:00:00') ENGINE = InnoDB,
PARTITION p202309 VALUES LESS THAN ('2023-10-01 00:00:00') ENGINE = InnoDB,
PARTITION p202310 VALUES LESS THAN ('2023-11-01 00:00:00') ENGINE = InnoDB,
PARTITION p202311 VALUES LESS THAN ('2023-12-01 00:00:00') ENGINE = InnoDB,
PARTITION p202312 VALUES LESS THAN ('2024-01-01 00:00:00') ENGINE = InnoDB,
PARTITION pmax VALUES LESS THAN (MAXVALUE) ENGINE = InnoDB)
总结
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MySQL使用分区表的好处: 1,可以把一些归类的数据放在一个分区中,可以减少服务器检查数据的数量加快查询.2,方便维护,通过删除分区来删除老的数据.3,分区数据可以被分布到不同的物理位置,可以做分布式有效利用多个硬盘驱动器. MySQL可以建立四种分区类型的分区: RANGE 分区:基于属于一个给定连续区间的列值,把多行分配给分区. LIST 分区:类似于按RANGE分区,区别在于LIST分区是基于列值匹配一个离散值集合中的某个值来进行选择. www.jb51.net HASH分区:基于用户
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Mysql分区表的管理与维护
改变一个表的分区方案只需使用alter table 加 partition_options 子句就可以了.和创建分区表时的create table语句很像. 创建表 CREATE TABLE trb3 (id INT, name VARCHAR(50), purchased DATE) PARTITION BY RANGE( YEAR(purchased) ) ( PARTITION p0 VALUES LESS THAN (1990), PARTITION p1 VALUES LESS THA
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MySQL分区表实现按月份归类
目录 建表 查看数据库文件: 插入 查询 删除 补充:Mysql自动按月表分区 MySQL单表数据量,建议不要超过2000W行,否则会对性能有较大影响.最近接手了一个项目,单表数据超7000W行,一条简单的查询语句等了50多分钟都没出结果,实在是难受,最终,我们决定用分区表. 建表 一般的表(innodb)创建后只有一个 idb 文件: create table normal_table(id int primary key, no int) 查看数据库文件: normal_table.ibd
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MySQL分区表的局限和限制详解
禁止构建 分区表达式不支持以下几种构建: 存储过程,存储函数,UDFS或者插件 声明变量或者用户变量 可以参考分区不支持的SQL函数 算术和逻辑运算符 分区表达式支持+,-,*算术运算,但是不支持DIV和/运算(还存在,可以查看Bug #30188, Bug #33182).但是,结果必须是整形或者NULL(线性分区键除外,想了解更多信息,可以查看分区类型). 分区表达式不支持位运算:|,&,^,<<,>>,~ . HANDLER语句 在MySQL 5.7.1之前的分区表不
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MySQL普通表如何转换成分区表
目录 版本: 前言: 改造分区前期条件: 分区改造案例: 总结 版本: MySQL-5.7.32 前言: 对于业务繁忙的数据库来说,在运行了一定时间后,往往会产生一些数据量较大的表,特别是对于每天新增数据较多的日志表或者流水表,大表对于日常的运维非常的不方便,特别是数据的清理.迁移,表的访问性能也会随着数据量的增大而受到影响,因此,对于大表我们需要进行优化拆分,通常拆分的方案有 所以,通常选择分区表改造方案的主要原因都是为了避免应用层面的改造,对应用层面透明,以及方便日常的运维,前提是表具备改造
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MYSQL将表名称修改成大写的存储过程
本文为大家分享了MYSQL将表名称修改成大写的存储过程,具体内容如下 1. 条件: 1.1 Mysql设置对大小写敏感 2. 执行下述存储过程: #call uppercase('库名') DROP PROCEDURE IF EXISTS uppercase; CREATE PROCEDURE uppercase(IN dbname VARCHAR(200)) BEGIN DECLARE done INT DEFAULT 0; DECLARE oldname VARCHAR(200); DEC
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jQuery序列化后的表单值转换成Json
小朋友有一个表单,他想以Json的方式获取到表单的内容.小朋友尝试了以下方式. 通过$("#form").serialize()可以获取到序列化的表单值字符串. 例如: a=1&b=2&c=3&d=4&e=5 通过$("#form").serializeArray()输出以数组形式序列化表单值. [ {name: 'firstname', value: 'Hello'}, {name: 'lastname', value: 'Worl
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MySQL slow_log表无法修改成innodb引擎详解
背景 从mysql.slow_log 获取慢查询日志很慢,该表是csv表,没有索引. 想添加索引来加速访问,而csv引擎不能添加索引(csv引擎存储是以逗号分割的文本来存储的),只能改存储引擎来添加索引了 mysql.slow_log表能改成myisam,不能改成innodb mysql> set global slow_query_log=off; Query OK, 0 rows affected (0.00 sec) mysql> alter table mysql.slow_log e
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MySql获取当前时间并转换成字符串的实现
目录 MySql获取当前时间的函数 时间转字符串 字符串转日期 MySql获取当前时间的函数 now(); select now(); //结果:2019-04-19 09:31:59 sysdate(); select SYSDATE(); //结果:2019-04-19 09:31:59 MySql 还有其他的一些函数,本人没用过 current_timestamp() current_timestamp localtime() localtime localtimestamp – (v4.
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MySQL从MyISAM转换成InnoDB错误与常用解决办法
原来自己用的是为了装的, 所以在设置database usage(如下图1)的时候按照discuz官方的建议,选的都是Non-Transactional Database Only(只支持MyISAM数据引擎的非事务数据库),用MyISAM数据库,还没涉及到需要InnoDB,因此打算直接不加载INNODB引擎.后来在做WordPress,一开始还不知道原来WordPress用的是InnoDB数据引擎,于是在原来的数据库里面就建了一个数据库,一开始也没发觉问题,安装,导入sql,都没问题,当时也没
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将MySQL从MyISAM转换成InnoDB错误和解决办法
后来在做WordPress,一开始还不知道原来WordPress用的是InnoDB数据引擎,于是在原来的数据库里面就建了一个数据库,一开始也没发觉问题,安装,导入sql,都没问题,当时也没多想.直到这几天因为又要装多一个WordPress,用phpmyadmin访问数据库多一点,问题来了.老是一访问WordPress的数据库,就弹出错误提示"Mysqld-nt.exe应用程序错误:"0x005346c4"指令引用的"0x00786000"内存,该内存不能为
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MySQL数据库表分区注意事项大全【推荐】
表分区与数据库分区是不一样的那么碰到表分区使用时我们要注意一些什么事情呢,今天我们来看一篇关于MySQL数据库表分区注意事项的细节. 1.分区列索引约束 若表有primary key或unique key,则分区表的分区列必须包含在primary key或unique key列表里,这是为了确保主键的效率,否则同一主键区的东西一个在A分区,一个在B分区,显然会比较麻烦. 2.各分区类型条件 range 每个分区包含那些分区表达式的值位于一个给定的连续区间内的行.这些区间要连续且不能相互重叠 li
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PHP实现驼峰样式字符串(首字母大写)转换成下划线样式字符串的方法示例
本文实例讲述了PHP实现驼峰样式字符串(首字母大写)转换成下划线样式字符串的方法.分享给大家供大家参考,具体如下: 1.如何在php中把驼峰样式的字符串转换成下划线样式的字符串.例:输入是FooBar的话,输出则是foo_bar 以下是用正则的方式去完成,既然用到正则,方法肯定就不只一种,我们看下下面的方式 echo strtolower(preg_replace('/(?<=[a-z])([A-Z])/', '_$1', 'fooBar')); //output:foo_bar echo &quo
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MySQL联表查询的简单示例
MySql会用到联表查询,对于刚学习的新手来说,可能会理解起来有难度.下面这篇文章就来给大家详细介绍MySQL联表查询的相关内容,分享出来供大家参考学习,下面话不多说了,来一起看看详细的介绍吧 关系型数据库,免不了表之间存在各种引用与关联.这些关联是通过主键与外键搭配来形成的.所以,取数据时,很大情况下单张表无法满足需求,额外的数据则需要将其他表加入到查询中来,这便是 JOIN 关键字完成的操作. MySQL 中 JOIN, CROSS JOIN 和 INNER JOIN 三者语法功能上相同,可