![]() You can use the statement SHOW BUILTINS to get a list of the available functions.įor more information, refer to the TiDB SQL Grammar. TiDB supports most of the built-in functions in MySQL, but not all. Although optimizer hints can be used in similar syntax to MySQL, the available hints and their implementation might differ.įor more information, refer to Understand the Query Execution Plan. In TiDB, the MySQL system variable optimizer_switch is read-only and has no effect on query plans. The output format, content, and privilege settings of Query Execution Plan ( EXPLAIN/ EXPLAIN FOR) in TiDB differ significantly 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. In TiDB, performance schema tables do not return any results. TiDB utilizes a combination of Prometheus and Grafana for storing and querying 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. Starting from v7.0.0, TiDB removes this restriction, allowing for more flexible table primary key definitions. TiDB does not support adding the AUTO_INCREMENT column attribute, and once removed, it cannot be recovered.įor 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. To remove the column attribute, use the ALTER TABLE MODIFY or ALTER TABLE CHANGE syntax. You can use the tidb_allow_remove_auto_inc system variable to allow or forbid removing the AUTO_INCREMENT column attribute. However, the IDs are not necessarily allocated sequentially, so it is recommended that you avoid mixing default and custom values to prevent encountering the Duplicated Error message. To make the IDs incremental among multiple TiDB servers, you can use the AUTO_INCREMENT MySQL compatibility mode. In TiDB, the auto-incremental column values (IDs) are globally unique and incremental within a single TiDB server. "Session Tracker: Add GTIDs context to the OK packet".CREATE TABLE tblName AS SELECT stmt syntax #4754.XA syntax (TiDB uses a two-phase commit internally, but this is not exposed via an SQL interface).Character sets other than ascii, latin1, binary, utf8, utf8mb4, and gbk.SPATIAL (also known as GIS/ GEOMETRY) functions, data types and indexes #6347.You can try out TiDB features on TiDB Playground. 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.Replicate data from MySQL: TiDB Data Migration (DM) is a tool that supports full data migration and incremental data replication from MySQL or MariaDB into TiDB.Instead, specific tools are provided to replicate data with MySQL: It's important to note that TiDB does not support the MySQL replication protocol. Additionally, some features might be difficult to implement in a distributed system. This could be because there is now a better way to solve the problem (such as the use of JSON instead of XML functions) or a lack of current demand versus effort required (such as stored procedures and functions). However, some features of MySQL are not supported in TiDB. The ecosystem tools for MySQL (PHPMyAdmin, Navicat, MySQL Workbench, DBeaver and more) and the MySQL client can be used for TiDB. TiDB is highly compatible with the MySQL protocol and the common features and syntax of MySQL 5.7 and MySQL 8.0.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |