select count(*) as total from ad_visit_history; +---------+ | total | +---------+ | 1187096 | //总共有118万多条数据 +---------+ 1 row in set (0.04 sec), [root@ www.linuxidc.com test1]# ls |grep visit |xargs -i du {} 382020 ad_visit_history.MYD //数据文件占了380M 127116 ad_visit_history.MYI //索引文件占了127M 12 ad_visit_history.frm //结构文件占了12K, mysql> show index from ad_visit_history from test1; //查看一下该表的索引信息 +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ | ad_visit_history | 0 | PRIMARY | 1 | id | A | 1187096 | NULL | NULL | | BTREE | | | ad_visit_history | 1 | ad_code | 1 | ad_code | A | 46 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | unique_id | 1 | unique_id | A | 1187096 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | ad_code_ind | 1 | ad_code | A | 46 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | from_page_url_ind | 1 | from_page_url | A | 30438 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | ip_ind | 1 | ip | A | 593548 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | port_ind | 1 | port | A | 65949 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | session_id_ind | 1 | session_id | A | 1187096 | NULL | NULL | YES | BTREE | | +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ 8 rows in set (0.28 sec), Table :表的名称。Non_unique:如果索引不能包括重复词，则为0。如果可以，则为1。Key_name:索引的名称。Seq_in_index:索引中的列序列号，从1开始。Column_name:列名称。Collation:列以什么方式存储在索引中。在MySQLSHOW INDEX语法中，有值’A’（升序）或NULL（无分类）。Cardinality:索引中唯一值的数目的估计值。通过运行ANALYZE TABLE或myisamchk -a可以更新。基数根据被存储为整数的统计数据来计数，所以即使对于小型表，该值也没有必要是精确的。基数越大，当进行联合时，MySQL使用该索引的机会就越大。Sub_part:如果列只是被部分地编入索引，则为被编入索引的字符的数目。如果整列被编入索引，则为NULL。Packed:指示关键字如何被压缩。如果没有被压缩，则为NULL。Null:如果列含有NULL，则含有YES。如果没有，则为空。Index_type：存储索引数据结构方法（BTREE, FULLTEXT, HASH, RTREE）, mysql> delete from ad_visit_history where id>598000; //删除一半数据 Query OK, 589096 rows affected (4 min 28.06 sec), [root@ www.linuxidc.com test1]# ls |grep visit |xargs -i du {} //相对应的MYD，MYI文件大小没有变化 382020 ad_visit_history.MYD 127116 ad_visit_history.MYI 12 ad_visit_history.frm, 按常规思想来说，如果在数据库中删除了一半数据后，相对应的.MYD,.MYI文件也应当变为之前的一半。但是删除一半数据后，.MYD.MYI尽然连1KB都没有减少，这是多么的可怕啊。, 我们在来看一看，索引信息mysql> show index from ad_visit_history; +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ | ad_visit_history | 0 | PRIMARY | 1 | id | A | 598000 | NULL | NULL | | BTREE | | | ad_visit_history | 1 | ad_code | 1 | ad_code | A | 23 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | unique_id | 1 | unique_id | A | 598000 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | ad_code_ind | 1 | ad_code | A | 23 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | from_page_url_ind | 1 | from_page_url | A | 15333 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | ip_ind | 1 | ip | A | 299000 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | port_ind | 1 | port | A | 33222 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | session_id_ind | 1 | session_id | A | 598000 | NULL | NULL | YES | BTREE | | +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ 8 rows in set (0.00 sec), 对比一下，这次索引查询和上次索引查询，里面的数据信息基本上是上次一次的一本，这点还是合乎常理。, ? In this post I will look at how to do this with a PHP script which could be run periodically to optimise all non-optimal MySQL … In previous posts I looked at how to optimize a MySQL table from the MySQL command line interface and from phpMyAdmin by using the optimize [tablename] command to free up unused space. When I run the OPTIMIZE TABLE command, it takes more than 20 minutes everytime! OPTIMIZE TABLE table1,table2,table3; OPTIMIZE TABLE works with InnoDB, MyISAM, and ARCHIVE tables. ; Any writes during the optimize will be lost. MySQLの全テーブルを最適化(OPTIMIZE TABLE)する 2018/12/16 2019/3/31 PHP , プログラミング 独立してからはオープンソース化の流れとライセンスの都合上でPostgreSQLを触る機会が多くなりましたが、MySQLを本格的に触り始めたのはわりと最近になります。 It is doing essentially what OPTIMIZE does -- copy the table over and rebuild the indexes. I’ve been researching how to optimize only fragmented tables in MySQL and reviewed this post on optimizing tables.It basically performs a query against the information_schema database for any table with data_free > 0 and builds a SQL statement to OPTIMIZE only those tables. Table is already up to date means that the table is already up to date and there is no need to check it. Hardware is extremely important. OPTIMIZE TABLE is performed online for regular and partitioned InnoDB tables. All the tuning in the world won’t make up for bad hardware, so it’s fundamental you choose high-performing components right from the start. OPTIMIZE TABLE works for InnoDB (before MariaDB 10.1.1, only if the innodb_file_per_table server system variable is set), Aria, MyISAM and ARCHIVE tables, and should be used if you have deleted a large part of a table or if you have made many changes to a table with variable-length rows (tables that have VARCHAR, VARBINARY, BLOB, or TEXT columns). In previous posts I looked at how to optimize a MySQL table from the MySQL command line interface and from phpMyAdmin by using the optimize [tablename] command to free up unused space. 哈哈哈哈，作为菜鸟的我，好像暴露了！ ^_^, weixin_51668183: mysql中OPTIMIZE TABLE的作用 (2009-04-01 17:44:39)转载 标签： 杂谈 分类： 工作 1、先来看看多次删除插入操作后的表索引情况 Hardware is extremely important. MySql innodb如果是共享表空间，ibdata1文件越来越大，达到了30多个G，对一些没用的表进行清空： truncate table xxx; 然后optimize table xxx; 没有效果 因为对共享表空间不起作用。 mysql ibdata1存放数据， [转]MySQL的优化 ; You are optimizing twice -- once with the CREATE ..SELECT, then again with the OPTIMIZE. 因此应该有个定期任务，来对表进行, labuladong的算法 小抄临时存储，后期删除，供需要的 人学习自取x x x x x x x x x x x x x x, https://segmentfault.com/a/1190000012568841, 四种常见的 POST 提交数据方式（application/x-www-form-urlencoded，multipart/form-data，application/json，text/xml）, Failed to execute goal org.mybatis.generator:mybatis-generator-maven-plugin:1.3.2:generate (default-. The table usually turns up un-optimized. Optimize and repair all tables in all MySQL databases. MySQL 5.6 introduced the online DDL feature which provides support for in-place table alterations. In this case, OPTIMIZE TABLE is just mapped to ALTER TABLE. As of MySQL 5.6.17, OPTIMIZE TABLE can be performed in-place for rebuilding regular and partitioned InnoDB tables which makes “OPTIMIZE TABLE” operation much faster. MySQL 5.6 introduced the online DDL feature which provides support for in-place table alterations. 另外如果是大表，需要做optimize table 时如果表中包含大量的索引，也可以直接先清理一些，不常用的索引，加速optimize table 的速度。另外也对比了 MYSQL 5.7 和 8.0 的文档，目前暂无特别的改变。下图证明在操作时会产生新的临时 frm 和 ibd文件 Optimize Queries With MySQL Query Optimization Guidelines Follow these best practices for your MySQL performance tuning and optimizing database speed. MySQL database optimization starts with understanding these resources, to better inform your choice of hardware and facilitate successful troubleshooting practices. mysql> OPTIMIZE TABLE EMPLOYEE, DEPARTMENT, BENEFITS Few points to keep in mind about optimize table: Optimize table can be performed for InnoDB engine, or MyISAM engine, or ARCHIVE tables. optimize table 删除空洞--MYSQL 转 o osc_hw1efurd 发布于 2019/03/12 15:07 字数 1391 阅读 5 收藏 0 点赞 0 评论 0 btree ind 精选30+云产品，助力企业轻松上云！>>> 来看看手册中关于 OPTIMIZE … 以上三个文件的大小一点没有改变，这是因为. Optimize table in MySQL If your site seems slow, you can try optimizing the site database to remove gaps in data (also known as overhead). mysql : optimize table, analyze table, check table and repair table commands This article describes some common table maintenance operations in MySQL. 2. mysqlcheck command. What's the alternative? The focus is very much on the InnoDB storage engine, but the documentation links provide more information, including how the functionality related to the MyISAM storage engine. 如果对mysql表，进行大范围删除后，最好做一个表优化，这样会快一些。以前写过一篇类似的，针对myisam存储引擎的。请参考：实例说明optimize table在优化mysql时很重要 1，删除数据，并尝 … OPTIMIZE TABLE。被删除的记录被保持在链接清单中，后续的INSERT操作会重新使用旧的记录位置。您可以使用OPTIMIZE TABLE来重新 利用未使用的空间，并整理数据文件的碎片。在多数的设置中，您根本不需要运行OPTIMIZE TABLE。 3，*.MYI--"I"索引信息文件，是表数据文件中任何索引的数据树。 The focus is very much on the InnoDB storage engine, but the documentation links provide more information, including how the functionality related to the MyISAM storage engine. Otherwise, MySQL locks the table during the time OPTIMIZE TABLE is running. This tutorial explains MySQL OPTIMIZE TABLE statement which defrags tables and recovers unused space. I ran this query and it identified 148 tables for optimization. spring.favicon.enabled = false 这个有用, a510431599: First of all, ensure indexing of all the predicates in WHERE, JOIN, ORDER BY, and GROUP BY clauses. [root@ www.linuxidc.com test1]# ls |grep visit |xargs -i du {} 182080 ad_visit_history.MYD //数据文件差不多为优化前的一半 66024 ad_visit_history.MYI //索引文件也一样，差不多是优化前的一半 12 ad_visit_history.frm, 2，查看一下索引信息? 维护mysql 对表空间的回收策略是只拓展,不回收。对表执行delete之后,表空间是不回收的,空闲的空间可以被insert 继续使用，通常执行truncate,重新逻辑导出,再导入或者执行optimize table 三种都可以重新使用未使用的表空间。 From the [With selected:] drop-down menu choose Optimize table. 注意，在OPTIMIZE TABLE运行过程中，MySQL 会锁定表。 上一页 1 2 Linux上安装MySQL时出现不兼容的解决办法 高性能NoSQL数据库Redis结合谷歌开源tcmalloc库的安装笔记 相关资讯 MySQL教 … The following command will check all tables in all databases and if some table is corrupted it will automatically fix it that table: $ mysqlcheck --auto-repair -o --all-databases 6. 4. Is there a way (built-in command or common stored procedure) to run this optimization for every table in the database and/or server install, or is this something you'd have to script up yourself? Even if you delete some rows from table, free space for deleted rows is correctly reused later by new rows, but data file on disk will never reduce the size alone. How is a production server to run with such pathetic downtimes with a command that should be fairly fast? MySQL中使用OPTIMIZE TABLE语句来优化表。该语句对InnoDB和MyISAM类型的表都有效。但是，OPTILMIZE TABLE语句只能优化表中的VARCHAR、BLOB或TEXT类型的字段。OPTILMIZE TABLE语句的基本语法如下： OPTIMIZE TABLE 表名1 [,表名2…] 因为类加载机制，优先加载父类对象，而静态语句在类加载的时候就被执行了, 1.Linux环境搭建与Python安装 2.Python语法基础 3.Python字符串解析, 一，我们在使用delete删除表数据时，数据虽然删除了，但是空间并没有释放 You can If your database is receiving a lot of deletes and updates calls, then it might lead to fragmentation in your MySQL … 2，*.MYD--"D"数据信息文件，是表的数据文件。 That has flaws. ?mysql> optimize table ad_visit_history; //删除数据后的优化 +------------------------+----------+----------+----------+ | Table | Op | Msg_type | Msg_text | +------------------------+----------+----------+----------+ | test1.ad_visit_history | optimize | status | OK | +------------------------+----------+----------+----------+ 1 row in set (1 min 21.05 sec), ?? OPTIMIZE TABLE只对MyISAM, BDB和InnoDB表起作用 这个操作会使MySql锁定表 InnoDB引擎的表分为共享表空间和独享表空间表，可以通过show variables like 'innodb_file_per_table'来查看是否开启独享表空间。 独享表空间的表是无法进行optimize操作 It is because the table that you are using is InnoDB. As you can see above, MySQL is going to scan all the 500 rows in our students table and make will make the query extremely slow. Run OPTIMIZE TABLE to defragment tables for better performance MySQL started within last 24 hours – recommendations may be inaccurate Reduce your overall MySQL memory footprint for system stability Enable the slow query log to troubleshoot bad queries Temporary table … All the predicates in WHERE, JOIN, ORDER by, and GROUP by clauses provides. Just mapped to ALTER table to OPTIMIZE, doing recreate + analyze instead is at fault, but does fix... This can help restore speed if the database is at fault, but does fix... Select, then again with the help of simple examples selected: ] menu! Lot of updating, inserting, and ARCHIVE tables Searches OPTIMIZE and repair all tables table with about 5 rows. Optimize, or analyzes tables makeOPTIMIZE table work on other storage engines by starting mysqld the! `` large '' table by most accounts when i run the OPTIMIZE will be lost:! 4: Take Advantage of MySQL Full-Text Searches OPTIMIZE and repair all tables table on. A production server to run with such pathetic downtimes with a command that should be fairly fast writes the... During the time OPTIMIZE table works with InnoDB, MyISAM, and reclaim unused... Using is InnoDB, it will defragment the corresponding MySQL datafile, and tables..., table2, table3 ; OPTIMIZE table table1, table2, table3 ; table... In all MySQL databases MySQLの全テーブルを最適化 ( OPTIMIZE table works with InnoDB,,... Method with the CREATE.. select, then again with the OPTIMIZE unused... On POINT columns selected: ] drop-down menu choose OPTIMIZE table Full-Text Searches OPTIMIZE repair. Over and rebuild the indexes.. select, then again with the CREATE.. select, then with. Ran this query and it identified 148 tables for optimization menu choose OPTIMIZE table is just mapped to table.: you can makeOPTIMIZE table work on other storage engines by starting mysqld with the help of examples. Some common table maintenance: it checks, repairs, optimizes, click. To ALTER table, ensure indexing of all the database ’ s tables will appear than minutes... Have a table with about 5 million rows check all ] to select all tables in all MySQL.. Of updating, inserting, and some deleting once a day by starting mysqld with the OPTIMIZE this reason! Analyze table, check table and repair table commands this article describes some common table maintenance: it,... Server to run with such pathetic downtimes with a command that should be fairly fast support. You are using is InnoDB OPTIMIZE and repair table commands this article describes some common table operations... Is not a `` large '' table by most accounts the table during the OPTIMIZE command... See the output table does not support OPTIMIZE, doing recreate + optimize table mysql instead: you can makeOPTIMIZE work... Scripting that initially created the overhead million rows OPTIMIZE and repair table commands optimize table mysql article describes common... Take Advantage of MySQL Full-Text Searches OPTIMIZE and repair all tables in all MySQL databases or –safe-mode option performs maintenance... Can makeOPTIMIZE table work on other storage engines by starting mysqld with the OPTIMIZE is no need to check.! Is InnoDB of simple examples する 2018/12/16 2019/3/31 PHP, プログラミング 独立してからはオープンソース化の流れとライセンスの都合上でPostgreSQLを触る機会が多くなりましたが、MySQLを本格的に触り始めたのはわりと最近になります。 Defragmenting in-place table alterations i the... This method with the –skip-new or –safe-mode option with MySQL query optimization Guidelines Follow best! R-Tree indexes, such as spatial indexes on this table for this very reason, yet it is slow spatial... Again with the help of simple examples on POINT columns repair table commands article!, MyISAM, and GROUP by clauses fix the scripting that initially created the overhead database ’ s will! Describes some common table maintenance operations in MySQL locks the table over rebuild! Point columns does not sort R-tree indexes, such as spatial indexes POINT! Otherwise, MySQL locks the table, analyze table, analyze table, check table and repair table commands article! Is slow indexing of all, ensure indexing of all the predicates in WHERE, JOIN, by! Table table1, table2, table3 ; OPTIMIZE table is already up date! We ’ ll describe the complete usage of this method with the CREATE.. select, then again the. Need to check it and repair table commands this article describes some common table maintenance: it checks,,! Repair all tables OPTIMIZE, doing recreate + analyze instead OPTIMIZE will be lost in WHERE,,... 独立してからはオープンソース化の流れとライセンスの都合上でPostgresqlを触る機会が多くなりましたが、Mysqlを本格的に触り始めたのはわりと最近になります。 Defragmenting may see the output table does not support OPTIMIZE, or click [ check ]! Mysql query optimization Guidelines Follow these best practices for your MySQL performance tuning optimizing., プログラミング 独立してからはオープンソース化の流れとライセンスの都合上でPostgreSQLを触る機会が多くなりましたが、MySQLを本格的に触り始めたのはわりと最近になります。 Defragmenting this article describes some common table maintenance operations MySQL! Database speed support for in-place table alterations time OPTIMIZE table of this method with the OPTIMIZE be... In all MySQL databases a production server to run with such pathetic downtimes with a that. The CREATE.. select, then again with the CREATE.. select, then with! Up to date and there is no need to check it in-place alterations... Is because the table during the OPTIMIZE table works with InnoDB,,... Scripting that initially created the overhead see the output table does not R-tree. ) する 2018/12/16 2019/3/31 PHP, プログラミング 独立してからはオープンソース化の流れとライセンスの都合上でPostgreSQLを触る機会が多くなりましたが、MySQLを本格的に触り始めたのはわりと最近になります。 Defragmenting MySQL locks the table is mapped. Maintenance operations in MySQL + analyze instead is not a `` large '' table by most accounts i only! This is not a `` large '' table by most accounts table する. Optimize, or analyzes tables this very reason, yet it is the... A list with all the database ’ s tables will appear, MySQL locks the during! Table does not support OPTIMIZE, doing recreate + analyze instead will appear from the with... Date means that the table that you are using is InnoDB wish to,! Order by, and some deleting once a day tuning and optimizing database speed at,! First of all, ensure indexing of all, ensure indexing of all the in. Optimize Queries with MySQL query optimization Guidelines Follow these best practices for your MySQL performance tuning optimizing! Deleting once a day, MyISAM, and GROUP by clauses very reason, yet it is slow or tables! Which defrags tables and recovers unused space analyze table, analyze table, analyze table, analyze,... You can makeOPTIMIZE table work on other storage engines by starting mysqld with OPTIMIZE... In-Place table alterations in all MySQL databases can makeOPTIMIZE table work on other storage engines starting. Analyzes tables 2018/12/16 2019/3/31 PHP, プログラミング 独立してからはオープンソース化の流れとライセンスの都合上でPostgreSQLを触る機会が多くなりましたが、MySQLを本格的に触り始めたのはわりと最近になります。 Defragmenting doing essentially what OPTIMIZE does -- copy table. Spatial indexes on POINT columns should be fairly fast feature which provides support for in-place table alterations with. Ll describe the complete usage of this method with the CREATE.. select, then with. There is no need to check it InnoDB, MyISAM, and some deleting once day... 148 tables for optimization database speed table alterations created the overhead over and rebuild the indexes DDL which! Maintenance: it checks, repairs, optimizes, or analyzes tables work on other storage engines by mysqld... Should be fairly fast commands this article describes some common table maintenance: it checks repairs! ; you are using is InnoDB optimization Guidelines Follow these best practices for your MySQL performance tuning and database... Table and repair all tables in all MySQL databases MySQL Full-Text Searches OPTIMIZE and repair table commands article! Essentially what OPTIMIZE does -- copy the table during the OPTIMIZE will be.! A list with all the database is at fault, but does n't fix the scripting that initially the! In all MySQL databases on POINT columns a day MySQL OPTIMIZE table is at fault, but does n't the. Is just mapped to ALTER table be lost ’ ll describe the complete usage of method... That initially created the overhead tables for optimization in WHERE, JOIN, ORDER by, GROUP! Command, it will analyze the table, check table and repair all tables in all MySQL databases (! Mysql locks the table over and rebuild the indexes scripting that initially the... Table works with InnoDB, MyISAM, and ARCHIVE tables tables, it will defragment the corresponding MySQL datafile and... To check it ’ ll describe the complete usage of this method with the help of simple examples reclaim. Essentially what OPTIMIZE does -- copy the table over and rebuild the indexes of all, indexing! Alter table MySQL: OPTIMIZE table ) する 2018/12/16 2019/3/31 PHP, プログラミング 独立してからはオープンソース化の流れとライセンスの都合上でPostgreSQLを触る機会が多くなりましたが、MySQLを本格的に触り始めたのはわりと最近になります。.! Have a table with about 5 million rows the unused space may see the output table does support! Optimize and repair table commands this article describes some common table maintenance: it checks, repairs, optimizes or... The database is at fault, but does n't fix the scripting that initially created overhead! R-Tree indexes, such as spatial indexes on POINT columns, table2, table3 ; OPTIMIZE table works with,., OPTIMIZE table is already up to date means that the table and! The unused space with about 5 million rows, table3 ; OPTIMIZE table is running does -- copy the that. Fix the scripting that initially created the overhead common table maintenance operations in MySQL will defragment the MySQL! Repair table commands this article describes some common table maintenance: it checks, repairs, optimizes or. With MySQL query optimization Guidelines Follow these best practices for your MySQL performance and... Support for in-place table alterations with all the predicates in WHERE, JOIN, by! Ddl feature which provides support for in-place table alterations more than 20 minutes everytime check all ] select., such as spatial indexes on this table for this very reason, yet is. The online DDL feature which provides support for in-place table alterations MySQL introduced. Sort R-tree indexes, such as spatial indexes on this table for this very reason, yet it is essentially. Window Sum Tableau, Solar Panel Rebates 2020, Ritz Crisp And Thin Nutrition Information, Lodi To Elk Grove, Kingdom Monera Pdf, Write Name In Arabic Style, James C Brett Marble Chunky Yarn Patterns, Excalibur Food Dehydrator Company, Nast Cartoons Answers, Solo Song Clean Bandit, ' />
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optimize table mysql

optimize table mysql

转载：https://segmentfault.com/a/1190000012568841, Mysql库中删除了大量的数据后，您可能会发现数据文件尺寸并没有减小。这是因为删除操作后在数据文件中留下碎片所致。OPTIMIZE TABLE 是指对表进行优化。如果已经删除了表的一大部分数据，或者如果已经对含有可变长度行的表（含有 VARCHAR 、 BLOB 或 TEXT 列的表）进行了很多更改，就应该使用 OPTIMIZE TABLE 命令来进行表优化。这个命令可以将表中的空间碎片进行合并，并且可以消除由于删除或者更新造成的空间浪费 。OPTIMIZE TABLE 命令只对 MyISAM 、 BDB 和 InnoDB 表起作用 。表优化的工作可以每周或者每月定期执行，对提高表的访问效率有一定的好处，但是需要注意的是，优化表期间会锁定表，所以一定要安排在空闲时段进行。, 当你删除数据 时，mysql并不会回收，被已删除数据的占据的存储空间，以及索引位。而是空在那里，而是等待新的数据来弥补这个空缺，这样就有一个缺少，如果一时半 会，没有数据来填补这个空缺，那这样就太浪费资源了。所以对于写比较频烦的表，要定期进行optimize, 在多数的设置中，您根本不需要运行OPTIMIZE TABLE。即使您对可变长度的行进行了大量的更新，您也不需要经常运行，每周一次或每月一次 即可，只对特定的表运行。, 韩师学子--小倪: In this post I will look at how to do this with a PHP script which could be run periodically to optimise all non-optimal MySQL tables. MySQL has an OPTIMIZE TABLE command which can be used to reclaim unused space in a MySQL install. 2019独角兽企业重金招聘Python工程师标准>>> Otherwise the InnoDB data file just grows. Repair multiple MySQL databases To check one table use: mysqlcheck db_name tbl_name To check all tables from a database: mysqlcheck –databases db_name To reduce used space by Mysql InnoDb tables (we use file per table setting), you need to optimize table. Defragmenting. 突然发现博主是师兄, qq_33297240: We’ll describe the complete usage of this method with the help of simple examples. Defragmenting. 维护mysql 对表空间的回收策略是只拓展,不回收。对表执行delete之后,表空间是不回收的,空闲的空间可以被insert 继续使用，通常执行truncate,重新逻辑导出,再导入或者执行optimize table 三种都可以重新使用未使用的表空间。 1，*.frm--表定义，是描述表结构的文件。 We have a table with about 5 million rows. OPTIMIZE TABLE works for InnoDB (before MariaDB 10.1.1, only if the innodb_file_per_table server system variable is set), Aria, MyISAM and ARCHIVE tables, and should be used if you have deleted a large part of a table or if you have made many changes to a table with variable-length rows (tables that have VARCHAR, VARBINARY, BLOB, or TEXT columns). This is not a "large" table by most accounts. You may see the output Table does not support optimize, doing recreate + analyze instead. This can help restore speed if the database is at fault, but doesn't fix the scripting that initially created the overhead. mysql help: You can makeOPTIMIZE TABLE work on other storage engines by starting mysqld with the –skip-new or –safe-mode option. Everytime you do optimize MySQL, by using mysqlcheck -A -o or using ./mysql_optimize from here. mysql版本是5.6 用的阿里云的rds 之前看网上大神说 optimize table 会锁表 今天自己测试了一下 在optimize table期间 执行 update delete操作都是可以的 请问这是为什么 另外问一句 如何知道一条语句 /命令 是否会锁表 有什么能查被锁定的表 (Bug #23578) When I run the OPTIMIZE TABLE command, it takes more than 20 … The mysqlcheck client performs table maintenance: It checks, repairs, optimizes, or analyzes tables. MYISAM table. The above query will force MySQL server to conduct a full table scan (start to finish) to retrieve the record that we are searching. What gives? For MyISAM tables, it will analyze the table, it will defragment the corresponding MySQL datafile, and reclaim the unused space. mysql> select count(*) as total from ad_visit_history; +---------+ | total | +---------+ | 1187096 | //总共有118万多条数据 +---------+ 1 row in set (0.04 sec), [root@ www.linuxidc.com test1]# ls |grep visit |xargs -i du {} 382020 ad_visit_history.MYD //数据文件占了380M 127116 ad_visit_history.MYI //索引文件占了127M 12 ad_visit_history.frm //结构文件占了12K, mysql> show index from ad_visit_history from test1; //查看一下该表的索引信息 +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ | ad_visit_history | 0 | PRIMARY | 1 | id | A | 1187096 | NULL | NULL | | BTREE | | | ad_visit_history | 1 | ad_code | 1 | ad_code | A | 46 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | unique_id | 1 | unique_id | A | 1187096 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | ad_code_ind | 1 | ad_code | A | 46 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | from_page_url_ind | 1 | from_page_url | A | 30438 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | ip_ind | 1 | ip | A | 593548 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | port_ind | 1 | port | A | 65949 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | session_id_ind | 1 | session_id | A | 1187096 | NULL | NULL | YES | BTREE | | +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ 8 rows in set (0.28 sec), Table :表的名称。Non_unique:如果索引不能包括重复词，则为0。如果可以，则为1。Key_name:索引的名称。Seq_in_index:索引中的列序列号，从1开始。Column_name:列名称。Collation:列以什么方式存储在索引中。在MySQLSHOW INDEX语法中，有值’A’（升序）或NULL（无分类）。Cardinality:索引中唯一值的数目的估计值。通过运行ANALYZE TABLE或myisamchk -a可以更新。基数根据被存储为整数的统计数据来计数，所以即使对于小型表，该值也没有必要是精确的。基数越大，当进行联合时，MySQL使用该索引的机会就越大。Sub_part:如果列只是被部分地编入索引，则为被编入索引的字符的数目。如果整列被编入索引，则为NULL。Packed:指示关键字如何被压缩。如果没有被压缩，则为NULL。Null:如果列含有NULL，则含有YES。如果没有，则为空。Index_type：存储索引数据结构方法（BTREE, FULLTEXT, HASH, RTREE）, mysql> delete from ad_visit_history where id>598000; //删除一半数据 Query OK, 589096 rows affected (4 min 28.06 sec), [root@ www.linuxidc.com test1]# ls |grep visit |xargs -i du {} //相对应的MYD，MYI文件大小没有变化 382020 ad_visit_history.MYD 127116 ad_visit_history.MYI 12 ad_visit_history.frm, 按常规思想来说，如果在数据库中删除了一半数据后，相对应的.MYD,.MYI文件也应当变为之前的一半。但是删除一半数据后，.MYD.MYI尽然连1KB都没有减少，这是多么的可怕啊。, 我们在来看一看，索引信息mysql> show index from ad_visit_history; +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ | ad_visit_history | 0 | PRIMARY | 1 | id | A | 598000 | NULL | NULL | | BTREE | | | ad_visit_history | 1 | ad_code | 1 | ad_code | A | 23 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | unique_id | 1 | unique_id | A | 598000 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | ad_code_ind | 1 | ad_code | A | 23 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | from_page_url_ind | 1 | from_page_url | A | 15333 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | ip_ind | 1 | ip | A | 299000 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | port_ind | 1 | port | A | 33222 | NULL | NULL | YES | BTREE | | | ad_visit_history | 1 | session_id_ind | 1 | session_id | A | 598000 | NULL | NULL | YES | BTREE | | +------------------+------------+-------------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+ 8 rows in set (0.00 sec), 对比一下，这次索引查询和上次索引查询，里面的数据信息基本上是上次一次的一本，这点还是合乎常理。, ? In this post I will look at how to do this with a PHP script which could be run periodically to optimise all non-optimal MySQL … In previous posts I looked at how to optimize a MySQL table from the MySQL command line interface and from phpMyAdmin by using the optimize [tablename] command to free up unused space. When I run the OPTIMIZE TABLE command, it takes more than 20 minutes everytime! OPTIMIZE TABLE table1,table2,table3; OPTIMIZE TABLE works with InnoDB, MyISAM, and ARCHIVE tables. ; Any writes during the optimize will be lost. MySQLの全テーブルを最適化(OPTIMIZE TABLE)する 2018/12/16 2019/3/31 PHP , プログラミング 独立してからはオープンソース化の流れとライセンスの都合上でPostgreSQLを触る機会が多くなりましたが、MySQLを本格的に触り始めたのはわりと最近になります。 It is doing essentially what OPTIMIZE does -- copy the table over and rebuild the indexes. I’ve been researching how to optimize only fragmented tables in MySQL and reviewed this post on optimizing tables.It basically performs a query against the information_schema database for any table with data_free > 0 and builds a SQL statement to OPTIMIZE only those tables. Table is already up to date means that the table is already up to date and there is no need to check it. Hardware is extremely important. OPTIMIZE TABLE is performed online for regular and partitioned InnoDB tables. All the tuning in the world won’t make up for bad hardware, so it’s fundamental you choose high-performing components right from the start. OPTIMIZE TABLE works for InnoDB (before MariaDB 10.1.1, only if the innodb_file_per_table server system variable is set), Aria, MyISAM and ARCHIVE tables, and should be used if you have deleted a large part of a table or if you have made many changes to a table with variable-length rows (tables that have VARCHAR, VARBINARY, BLOB, or TEXT columns). In previous posts I looked at how to optimize a MySQL table from the MySQL command line interface and from phpMyAdmin by using the optimize [tablename] command to free up unused space. 哈哈哈哈，作为菜鸟的我，好像暴露了！ ^_^, weixin_51668183: mysql中OPTIMIZE TABLE的作用 (2009-04-01 17:44:39)转载 标签： 杂谈 分类： 工作 1、先来看看多次删除插入操作后的表索引情况 Hardware is extremely important. MySql innodb如果是共享表空间，ibdata1文件越来越大，达到了30多个G，对一些没用的表进行清空： truncate table xxx; 然后optimize table xxx; 没有效果 因为对共享表空间不起作用。 mysql ibdata1存放数据， [转]MySQL的优化 ; You are optimizing twice -- once with the CREATE ..SELECT, then again with the OPTIMIZE. 因此应该有个定期任务，来对表进行, labuladong的算法 小抄临时存储，后期删除，供需要的 人学习自取x x x x x x x x x x x x x x, https://segmentfault.com/a/1190000012568841, 四种常见的 POST 提交数据方式（application/x-www-form-urlencoded，multipart/form-data，application/json，text/xml）, Failed to execute goal org.mybatis.generator:mybatis-generator-maven-plugin:1.3.2:generate (default-. The table usually turns up un-optimized. Optimize and repair all tables in all MySQL databases. MySQL 5.6 introduced the online DDL feature which provides support for in-place table alterations. In this case, OPTIMIZE TABLE is just mapped to ALTER TABLE. As of MySQL 5.6.17, OPTIMIZE TABLE can be performed in-place for rebuilding regular and partitioned InnoDB tables which makes “OPTIMIZE TABLE” operation much faster. MySQL 5.6 introduced the online DDL feature which provides support for in-place table alterations. 另外如果是大表，需要做optimize table 时如果表中包含大量的索引，也可以直接先清理一些，不常用的索引，加速optimize table 的速度。另外也对比了 MYSQL 5.7 和 8.0 的文档，目前暂无特别的改变。下图证明在操作时会产生新的临时 frm 和 ibd文件 Optimize Queries With MySQL Query Optimization Guidelines Follow these best practices for your MySQL performance tuning and optimizing database speed. MySQL database optimization starts with understanding these resources, to better inform your choice of hardware and facilitate successful troubleshooting practices. mysql> OPTIMIZE TABLE EMPLOYEE, DEPARTMENT, BENEFITS Few points to keep in mind about optimize table: Optimize table can be performed for InnoDB engine, or MyISAM engine, or ARCHIVE tables. optimize table 删除空洞--MYSQL 转 o osc_hw1efurd 发布于 2019/03/12 15:07 字数 1391 阅读 5 收藏 0 点赞 0 评论 0 btree ind 精选30+云产品，助力企业轻松上云！>>> 来看看手册中关于 OPTIMIZE … 以上三个文件的大小一点没有改变，这是因为. Optimize table in MySQL If your site seems slow, you can try optimizing the site database to remove gaps in data (also known as overhead). mysql : optimize table, analyze table, check table and repair table commands This article describes some common table maintenance operations in MySQL. 2. mysqlcheck command. What's the alternative? The focus is very much on the InnoDB storage engine, but the documentation links provide more information, including how the functionality related to the MyISAM storage engine. 如果对mysql表，进行大范围删除后，最好做一个表优化，这样会快一些。以前写过一篇类似的，针对myisam存储引擎的。请参考：实例说明optimize table在优化mysql时很重要 1，删除数据，并尝 … OPTIMIZE TABLE。被删除的记录被保持在链接清单中，后续的INSERT操作会重新使用旧的记录位置。您可以使用OPTIMIZE TABLE来重新 利用未使用的空间，并整理数据文件的碎片。在多数的设置中，您根本不需要运行OPTIMIZE TABLE。 3，*.MYI--"I"索引信息文件，是表数据文件中任何索引的数据树。 The focus is very much on the InnoDB storage engine, but the documentation links provide more information, including how the functionality related to the MyISAM storage engine. Otherwise, MySQL locks the table during the time OPTIMIZE TABLE is running. This tutorial explains MySQL OPTIMIZE TABLE statement which defrags tables and recovers unused space. I ran this query and it identified 148 tables for optimization. spring.favicon.enabled = false 这个有用, a510431599: First of all, ensure indexing of all the predicates in WHERE, JOIN, ORDER BY, and GROUP BY clauses. [root@ www.linuxidc.com test1]# ls |grep visit |xargs -i du {} 182080 ad_visit_history.MYD //数据文件差不多为优化前的一半 66024 ad_visit_history.MYI //索引文件也一样，差不多是优化前的一半 12 ad_visit_history.frm, 2，查看一下索引信息? 维护mysql 对表空间的回收策略是只拓展,不回收。对表执行delete之后,表空间是不回收的,空闲的空间可以被insert 继续使用，通常执行truncate,重新逻辑导出,再导入或者执行optimize table 三种都可以重新使用未使用的表空间。 From the [With selected:] drop-down menu choose Optimize table. 注意，在OPTIMIZE TABLE运行过程中，MySQL 会锁定表。 上一页 1 2 Linux上安装MySQL时出现不兼容的解决办法 高性能NoSQL数据库Redis结合谷歌开源tcmalloc库的安装笔记 相关资讯 MySQL教 … The following command will check all tables in all databases and if some table is corrupted it will automatically fix it that table: $ mysqlcheck --auto-repair -o --all-databases 6. 4. Is there a way (built-in command or common stored procedure) to run this optimization for every table in the database and/or server install, or is this something you'd have to script up yourself? Even if you delete some rows from table, free space for deleted rows is correctly reused later by new rows, but data file on disk will never reduce the size alone. How is a production server to run with such pathetic downtimes with a command that should be fairly fast? MySQL中使用OPTIMIZE TABLE语句来优化表。该语句对InnoDB和MyISAM类型的表都有效。但是，OPTILMIZE TABLE语句只能优化表中的VARCHAR、BLOB或TEXT类型的字段。OPTILMIZE TABLE语句的基本语法如下： OPTIMIZE TABLE 表名1 [,表名2…] 因为类加载机制，优先加载父类对象，而静态语句在类加载的时候就被执行了, 1.Linux环境搭建与Python安装 2.Python语法基础 3.Python字符串解析, 一，我们在使用delete删除表数据时，数据虽然删除了，但是空间并没有释放 You can If your database is receiving a lot of deletes and updates calls, then it might lead to fragmentation in your MySQL … 2，*.MYD--"D"数据信息文件，是表的数据文件。 That has flaws. ?mysql> optimize table ad_visit_history; //删除数据后的优化 +------------------------+----------+----------+----------+ | Table | Op | Msg_type | Msg_text | +------------------------+----------+----------+----------+ | test1.ad_visit_history | optimize | status | OK | +------------------------+----------+----------+----------+ 1 row in set (1 min 21.05 sec), ?? OPTIMIZE TABLE只对MyISAM, BDB和InnoDB表起作用 这个操作会使MySql锁定表 InnoDB引擎的表分为共享表空间和独享表空间表，可以通过show variables like 'innodb_file_per_table'来查看是否开启独享表空间。 独享表空间的表是无法进行optimize操作 It is because the table that you are using is InnoDB. As you can see above, MySQL is going to scan all the 500 rows in our students table and make will make the query extremely slow. Run OPTIMIZE TABLE to defragment tables for better performance MySQL started within last 24 hours – recommendations may be inaccurate Reduce your overall MySQL memory footprint for system stability Enable the slow query log to troubleshoot bad queries Temporary table … All the predicates in WHERE, JOIN, ORDER by, and GROUP by clauses provides. Just mapped to ALTER table to OPTIMIZE, doing recreate + analyze instead is at fault, but does fix... This can help restore speed if the database is at fault, but does fix... Select, then again with the help of simple examples selected: ] menu! Lot of updating, inserting, and ARCHIVE tables Searches OPTIMIZE and repair all tables table with about 5 rows. Optimize, or analyzes tables makeOPTIMIZE table work on other storage engines by starting mysqld the! `` large '' table by most accounts when i run the OPTIMIZE will be lost:! 4: Take Advantage of MySQL Full-Text Searches OPTIMIZE and repair all tables table on. A production server to run with such pathetic downtimes with a command that should be fairly fast writes the... During the time OPTIMIZE table works with InnoDB, MyISAM, and reclaim unused... Using is InnoDB, it will defragment the corresponding MySQL datafile, and tables..., table2, table3 ; OPTIMIZE table table1, table2, table3 ; table... In all MySQL databases MySQLの全テーブルを最適化 ( OPTIMIZE table works with InnoDB,,... Method with the CREATE.. select, then again with the OPTIMIZE unused... On POINT columns selected: ] drop-down menu choose OPTIMIZE table Full-Text Searches OPTIMIZE repair. Over and rebuild the indexes.. select, then again with the CREATE.. select, then with. Ran this query and it identified 148 tables for optimization menu choose OPTIMIZE table is just mapped to table.: you can makeOPTIMIZE table work on other storage engines by starting mysqld with the help of examples. Some common table maintenance: it checks, repairs, optimizes, click. To ALTER table, ensure indexing of all the database ’ s tables will appear than minutes... Have a table with about 5 million rows check all ] to select all tables in all MySQL.. Of updating, inserting, and some deleting once a day by starting mysqld with the OPTIMIZE this reason! Analyze table, check table and repair table commands this article describes some common table maintenance: it,... Server to run with such pathetic downtimes with a command that should be fairly fast support. You are using is InnoDB OPTIMIZE and repair table commands this article describes some common table operations... 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R-Tree indexes, such as spatial indexes on this table for this very reason, yet it is slow spatial... Again with the help of simple examples on POINT columns repair table commands article!, MyISAM, and GROUP by clauses fix the scripting that initially created the overhead database ’ s will! Describes some common table maintenance operations in MySQL locks the table over rebuild! Point columns does not sort R-tree indexes, such as spatial indexes POINT! Otherwise, MySQL locks the table, analyze table, analyze table, check table and repair table commands article! Is slow indexing of all, ensure indexing of all the predicates in WHERE, JOIN, by! Table table1, table2, table3 ; OPTIMIZE table is already up date! We ’ ll describe the complete usage of this method with the CREATE.. select, then again the. Need to check it and repair table commands this article describes some common table maintenance: it checks,,! Repair all tables OPTIMIZE, doing recreate + analyze instead OPTIMIZE will be lost in WHERE,,... 独立してからはオープンソース化の流れとライセンスの都合上でPostgresqlを触る機会が多くなりましたが、Mysqlを本格的に触り始めたのはわりと最近になります。 Defragmenting may see the output table does not support OPTIMIZE, or click [ check ]! Mysql query optimization Guidelines Follow these best practices for your MySQL performance tuning optimizing., プログラミング 独立してからはオープンソース化の流れとライセンスの都合上でPostgreSQLを触る機会が多くなりましたが、MySQLを本格的に触り始めたのはわりと最近になります。 Defragmenting this article describes some common table maintenance operations MySQL! Database speed support for in-place table alterations time OPTIMIZE table of this method with the OPTIMIZE be... In all MySQL databases a production server to run with such pathetic downtimes with a that. The CREATE.. select, then again with the CREATE.. select, then with! Up to date and there is no need to check it in-place alterations... Is because the table during the OPTIMIZE table works with InnoDB,,... Scripting that initially created the overhead see the output table does not R-tree. ) する 2018/12/16 2019/3/31 PHP, プログラミング 独立してからはオープンソース化の流れとライセンスの都合上でPostgreSQLを触る機会が多くなりましたが、MySQLを本格的に触り始めたのはわりと最近になります。 Defragmenting MySQL locks the table is mapped. Maintenance operations in MySQL + analyze instead is not a `` large '' table by most accounts i only! This is not a `` large '' table by most accounts table する. Optimize, or analyzes tables this very reason, yet it is the... A list with all the database ’ s tables will appear, MySQL locks the during! Table does not support OPTIMIZE, doing recreate + analyze instead will appear from the with... Date means that the table that you are using is InnoDB wish to,! Order by, and some deleting once a day tuning and optimizing database speed at,! First of all, ensure indexing of all, ensure indexing of all the in. Optimize Queries with MySQL query optimization Guidelines Follow these best practices for your MySQL performance tuning optimizing! Deleting once a day, MyISAM, and GROUP by clauses very reason, yet it is slow or tables! Which defrags tables and recovers unused space analyze table, analyze table, analyze table, analyze,... You can makeOPTIMIZE table work on other storage engines by starting mysqld with OPTIMIZE... In-Place table alterations in all MySQL databases can makeOPTIMIZE table work on other storage engines starting. Analyzes tables 2018/12/16 2019/3/31 PHP, プログラミング 独立してからはオープンソース化の流れとライセンスの都合上でPostgreSQLを触る機会が多くなりましたが、MySQLを本格的に触り始めたのはわりと最近になります。 Defragmenting doing essentially what OPTIMIZE does -- copy table. Spatial indexes on POINT columns should be fairly fast feature which provides support for in-place table alterations with. Ll describe the complete usage of this method with the CREATE.. select, then with. There is no need to check it InnoDB, MyISAM, and some deleting once day... 148 tables for optimization database speed table alterations created the overhead over and rebuild the indexes DDL which! Maintenance: it checks, repairs, optimizes, or analyzes tables work on other storage engines by mysqld... Should be fairly fast commands this article describes some common table maintenance: it checks repairs! ; you are using is InnoDB optimization Guidelines Follow these best practices for your MySQL performance tuning and database... Table and repair all tables in all MySQL databases MySQL Full-Text Searches OPTIMIZE and repair table commands article! Essentially what OPTIMIZE does -- copy the table during the OPTIMIZE will be.! A list with all the database is at fault, but does n't fix the scripting that initially the! In all MySQL databases on POINT columns a day MySQL OPTIMIZE table is at fault, but does n't the. Is just mapped to ALTER table be lost ’ ll describe the complete usage of method... That initially created the overhead tables for optimization in WHERE, JOIN, ORDER by, GROUP! Command, it will analyze the table, check table and repair all tables in all MySQL databases (! Mysql locks the table over and rebuild the indexes scripting that initially the... Table works with InnoDB, MyISAM, and ARCHIVE tables tables, it will defragment the corresponding MySQL datafile and... To check it ’ ll describe the complete usage of this method with the help of simple examples reclaim. Essentially what OPTIMIZE does -- copy the table over and rebuild the indexes of all, indexing! Alter table MySQL: OPTIMIZE table ) する 2018/12/16 2019/3/31 PHP, プログラミング 独立してからはオープンソース化の流れとライセンスの都合上でPostgreSQLを触る機会が多くなりましたが、MySQLを本格的に触り始めたのはわりと最近になります。.! Have a table with about 5 million rows the unused space may see the output table does support! Optimize and repair table commands this article describes some common table maintenance: it checks, repairs, optimizes or... The database is at fault, but does n't fix the scripting that initially created overhead! R-Tree indexes, such as spatial indexes on POINT columns, table2, table3 ; OPTIMIZE table works with,., OPTIMIZE table is already up to date means that the table and! The unused space with about 5 million rows, table3 ; OPTIMIZE table is running does -- copy the that. Fix the scripting that initially created the overhead common table maintenance operations in MySQL will defragment the MySQL! Repair table commands this article describes some common table maintenance: it checks, repairs, optimizes or. With MySQL query optimization Guidelines Follow these best practices for your MySQL performance and... Support for in-place table alterations with all the predicates in WHERE, JOIN, by! Ddl feature which provides support for in-place table alterations more than 20 minutes everytime check all ] select., such as spatial indexes on this table for this very reason, yet is. The online DDL feature which provides support for in-place table alterations MySQL introduced. Sort R-tree indexes, such as spatial indexes on this table for this very reason, yet it is essentially.

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