和 SPATIAL 索引。 index_col_name 支持长度选项，最大长度限制为3072字节，该长度限制不根据建表时使用的存储引擎、字符 集而变。这是因为 TiDB 并非使用 Innodb 、 MyISAM 等存储引擎，因此，仅对建表时的存储引擎选项进 行了 MySQL 语法上的兼容。对于字符集，TiDB 使用的是 utf8mb4 字符集，对于建表时的字符集选项同样 仅有 MySQL PARSER 选项。 index_type 支持 BTREE 和 HASH ，但仅有 MySQL 语法上的支持，即索引类型与建表语句中的存储 引擎选项无关。举例：在 MySQL 中，使用 Innodb 的表，在 CREATE INDEX 时只能使用 BTREE 索 CREATE INDEX 语法 与 MySQL 的差异 数据定义语句 (DDL) - 143 - 本文档使用 书栈(BookStack 也可以使用 HASH 。 MySQL 的 algorithm_option 和 lock_option 选项 TiDB 仅作语法支持。 TiDB 单表最多支持 512 个列。InnoDB 的限制是 1017。MySQL 的硬限制是 4096。详见 MySQL 文档 Limits on Table Column Count and Row Size 1. DROP INDEX index_name

B的表设计的key过⻓，全量同步时会报错。 如果⼀定要使⽤udb-mysql5.6版本，需如下操作： 1.⽬标端启⽤系统变量innodb_large_prefix 1).系统变量innodb_large_prefix为ON 2).系统变量innodb_file_format为Barracuda 如果⽤⼾权限不够，先调整⾃⼰的super权限： mysql>update mysql Copyright © 2012-2021 UCloud 优刻得 116/120 mysql>flush privileges; mysql>set global innodb_large_prefix=on; mysql>set global innodb_file_format=Barracuda; 2.源端需要修改表属性： mysql> ALTER TABLE TEST ROW_FORMAT=DYNAMIC;

in TiDB than in MySQL, in that it is a relatively lightweight and short-lived operation in MySQL/InnoDB, while in TiDB it completely re- builds the statistics for a table and can take much longer to complete create tables with alternative storage engines. In implementation, TiDB describes the metadata as the InnoDB storage engine. TiDB supports storage engine abstraction similar to MySQL, but you need to specify table player_jpa (id bigint not null, coins integer, goods �→ integer, primary key (id)) engine=InnoDB 2023-01-05T14:06:55.332+08:00 INFO 22005 --- [ main] o.h.e.t.j.p.i. �→ JtaPlatformInitiator : HHH000490:

in TiDB than in MySQL, in that it is a relatively lightweight and short-lived operation in MySQL/InnoDB, while in TiDB it completely re- builds the statistics for a table and can take much longer to complete create tables with alternative storage engines. In implementation, TiDB describes the metadata as the InnoDB storage engine. TiDB supports storage engine abstraction similar to MySQL, but you need to specify NULL, `comment` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `sid` (`sid`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 The id column is the primary key, and the sid column is the sharding key

For TiDB v6.6.0 and earlier versions, auto-increment columns in TiDB behave the same as in MySQL InnoDB, requiring them to be primary keys or index prefixes. Starting from v7.0.0, TiDB removes this restriction making it a more resource-intensive operation that takes longer to complete. In contrast, MySQL/InnoDB performs a relatively lightweight and short-lived operation. For more information, refer to ANALYZE created with alternative storage engines. Despite this, the metadata as described by TiDB is for the InnoDB storage engine as a way to ensure compatibility. To specify a storage engine using the --store option

For TiDB v6.6.0 and earlier versions, auto-increment columns in TiDB behave the same as in MySQL InnoDB, requiring them to be primary keys or index prefixes. Starting from v7.0.0, TiDB removes this restriction making it a more resource-intensive operation that takes longer to complete. In contrast, MySQL/InnoDB performs a relatively lightweight and short-lived operation. For more information, refer to ANALYZE created with alternative storage engines. Despite this, the metadata as described by TiDB is for the InnoDB storage engine as a way to ensure compatibility. To specify a storage engine using the --store option

in TiDB than in MySQL, in that it is a relatively lightweight and short-lived operation in MySQL/InnoDB, while in TiDB it completely re- builds the statistics for a table and can take much longer to complete create tables with alternative storage engines. In implementation, TiDB describes the metadata as the InnoDB storage engine. TiDB supports storage engine abstraction similar to MySQL, but you need to specify had.', `createdAt` DATETIME NOT NULL, `updatedAt` DATETIME NOT NULL, �→ PRIMARY KEY (`id`)) ENGINE=InnoDB; Executing (default): SHOW INDEX FROM `players` Executing (default): INSERT INTO `players` (`id`

For TiDB v6.6.0 and earlier versions, auto-increment columns in TiDB behave the same as in MySQL InnoDB, requiring them to be primary keys or index prefixes. Starting from v7.0.0, TiDB removes this restriction making it a more resource-intensive operation that takes longer to complete. In contrast, MySQL/InnoDB performs a relatively lightweight and short-lived operation. For more information, refer to ANALYZE created with alternative storage engines. Despite this, the metadata as described by TiDB is for the InnoDB storage engine as a way to ensure compatibility. To specify a storage engine using the --store option

in TiDB than in MySQL, in that it is a relatively lightweight and short-lived operation in MySQL/InnoDB, while in TiDB it completely re- builds the statistics for a table and can take much longer to complete create tables with alternative storage engines. In implementation, TiDB describes the metadata as the InnoDB storage engine. TiDB supports storage engine abstraction similar to MySQL, but you need to specify mode, transactions wait for locks of each other. The timeout for waiting a lock is defined by the innodb_lock_wait_timeout parameter of TiDB. This is the maximum wait lock time at the SQL statement level

For TiDB v6.6.0 and earlier versions, auto-increment columns in TiDB behave the same as in MySQL InnoDB, requiring them to be primary keys or index prefixes. Starting from v7.0.0, TiDB removes this restriction making it a more resource-intensive operation that takes longer to complete. In contrast, MySQL/InnoDB performs a relatively lightweight and short-lived operation. For more information, refer to ANALYZE created with alternative storage engines. Despite this, the metadata as described by TiDB is for the InnoDB storage engine as a way to ensure compatibility. To specify a storage engine using the --store option