See Understand the Query Execution Plan for more details. You can also use optimizer hints in similar syntax to MySQL, but the available hints and implementation might differ. The MySQL system variable optimizer_switch is read-only in TiDB and has no effect on query plans. The output format, output content, and the privilege setting of Query Execution Plan ( EXPLAIN/ EXPLAIN FOR) in TiDB is greatly different from those in MySQL. Performance schema tables return empty results in TiDB. To check performance metrics in TiDB Cloud, you can either check the cluster overview page on the TiDB Cloud console or use third-party monitoring integrations. TiDB uses a combination of Prometheus and Grafana to store and query the performance monitoring metrics. It is recommended to use AUTO_RANDOM instead. See Troubleshoot HotSpot Issues for details. The AUTO_INCREMENT attribute might cause hotspot in production environments.
TiDB does not support adding the AUTO_INCREMENT column attribute, and this attribute cannot be recovered once it is removed. The syntax of removing the column attribute is ALTER TABLE MODIFY or ALTER TABLE CHANGE. You can use the tidb_allow_remove_auto_inc system variable to allow or forbid removing the AUTO_INCREMENT column attribute. Otherwise, you might encounter the Duplicated Error error message. It is recommended that you do not mix default values and custom values. They are incremental on a single TiDB server, but not necessarily incremental among multiple TiDB servers or allocated sequentially. In TiDB, auto-incremental columns are globally unique.
SPATIAL (also known as GIS/ GEOMETRY) functions, data types and indexes #6347.TiCDC uses the MySQL sink to replicate the incremental data of TiDB to MySQL.įor information about transaction differences between MySQL and TiDB, see Pessimistic Transaction Mode. Replicate data to MySQL: TiCDC is a tool for replicating the incremental data of TiDB by pulling TiKV change logs.
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Replicate data from MySQL: TiDB Data Migration (DM) is a tool that supports the full data migration and the incremental data replication from MySQL/MariaDB into TiDB.In addition, TiDB does not support the MySQL replication protocol, but provides specific tools to replicate data with MySQL.Some features might also be difficult to implement as a distributed system. This could be because there is now a better way to solve the problem (such as XML functions superseded by JSON), or a lack of current demand versus effort required (such as stored procedures and functions).
However, some features of MySQL are not supported. The ecosystem tools for MySQL 5.7 (PHPMyAdmin, Navicat, MySQL Workbench, mysqldump, and Mydumper/myloader) and the MySQL client can be used for TiDB. TiDB is highly compatible with the MySQL 5.7 protocol and the common features and syntax of MySQL 5.7.