particularly novel, other options in the market provide fairly similar features in this particular respect (Vitess and CRDB). It is instead a combination of these market-defining focuses and additional features based on traffic and need, but most of these solutions do not automatically scale across nodes. Vitess CRDB PHXSQL 5 SPECIFIC FEATURES TIDB MYSQL COMPATIBILITY ECOSYSTEM REAL-TIME ANALYTICS HIGH LEVEL highlight that there exists a range of solutions that are up to date and supported. So for example Vitess has an Operator tool, this lacks support which results in issues while trying to set it up with

3.分布式数据库 类库/框架 数据库中间件 分布式数据库 数据网格 TDDL Sharding-JDBC DRDS Sharding-Proxy MyCAT DBLE KingShard Vitess ? Spanner Aurora GaussDB PolarDB OceanBase TiDB Cockroach DB …… 3.分布式数据库 1.水平扩展性 2.计算存储分离 3

merge MySQL shards into TiDB· · · · · · · · · · · · · · · · · · · · · · 788 6.1.4 Migrate data from Vitess to TiDB · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 788 6.1.5 Migrate data from Migrate and Merge MySQL Shards of Large Datasets to TiDB · · · · · · · 835 6.4.6 Migrate Data from Vitess to TiDB · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 853 6.4.7 Migrate Data from Large Datasets to TiDB 6.1.4 Migrate data from Vitess to TiDB To migrate data from Vitess to TiDB, the following guide is available: • Migrate Data from Vitess to TiDB 6.1.5 Migrate data from files to TiDB

从大数据量分库分表 MySQL 合并迁移数据到 TiDB · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 648 6.4.6 从 Vitess 迁移数据到 TiDB · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · DM 进行增量数据 (Binlog) 的分 表同步。 • 从大数据量分库分表 MySQL 合并迁移数据到 TiDB 6.1.3.1 将数据从 Vitess 迁移到 TiDB 将数据从 Vitess 迁移到 TiDB，可参考以下文档： • 从 Vitess 迁移数据到 TiDB 6.1.4 从文件迁移数据到 TiDB • 从 CSV 文件迁移数据到 TiDB • 从 SQL 文件迁移数据到 6 从 Vitess 迁移数据到 TiDB 本文档介绍了将数据从 Vitess 迁移到 TiDB 时可以采用的工具。 由于 Vitess 的后端基于 MySQL，当从 Vitess 迁移数据到 TiDB 时，你可以直接使用 MySQL 适用的迁移数据工具， 如Dumpling、TiDB Lightning 和TiDB Data Migration (DM)。需要注意的是，针对 Vitess 中的每个分片，你都需要进行

json_storage_size, json_type, json_unquote, json_ �→ valid, lower, md5, reverse, tidb_shard, upper, vitess_hash • This read-only variable is used to show the functions that are allowed to be used for creating JSON_TYPE() • JSON_UNQUOTE() • JSON_VALID() • LOWER() • MD5() • REVERSE() • TIDB_SHARD() • UPPER() • VITESS_HASH() For the functions that are not included in the above list, those functions are not fully utc_timestamp | | uuid | | uuid_short | | uuid_to_bin | | validate_password_strength | | version | | vitess_hash | | week | | weekday | | weekofyear | | weight_string | | xor | | year | | yearweek |

json_storage_size, json_type, json_unquote, json_ �→ valid, lower, md5, reverse, tidb_shard, upper, vitess_hash • This read-only variable is used to show the functions that are allowed to be used for creating JSON_TYPE() • JSON_UNQUOTE() • JSON_VALID() • LOWER() 4078 • MD5() • REVERSE() • TIDB_SHARD() • UPPER() • VITESS_HASH() For the functions that are not included in the above list, those functions are not fully utc_timestamp | | uuid | | uuid_short | | uuid_to_bin | | validate_password_strength | | version | | vitess_hash | | week | | weekday | | weekofyear | | weight_string | | xor | | year | | yearweek |

json_storage_size, json_type, json_unquote, json_ �→ valid, lower, md5, reverse, tidb_shard, upper, vitess_hash • This read-only variable is used to show the functions that are allowed to be used for creating JSON_TYPE() • JSON_UNQUOTE() • JSON_VALID() • LOWER() • MD5() • REVERSE() • TIDB_SHARD() • UPPER() • VITESS_HASH() For the functions that are not included in the above list, those functions are not fully build information. VITESS_HASH() Returns the hash of a number. This function is compatible with the HASH function of Vitess, and is intended to help the data migration from Vitess. 14.12.4.22.1 CURRENT_RESOURCE_GROUP

json_storage_size, json_type, json_unquote, json_ �→ valid, lower, md5, reverse, tidb_shard, upper, vitess_hash • This read-only variable is used to show the functions that are allowed to be used for creating JSON_TYPE() • JSON_UNQUOTE() • JSON_VALID() • LOWER() • MD5() • REVERSE() • TIDB_SHARD() • UPPER() 3985 • VITESS_HASH() For the functions that are not included in the above list, those functions are not fully build information. VITESS_HASH() Returns the hash of a number. This function is compatible with the HASH function of Vitess, and is intended to help the data migration from Vitess. 14.12.4.22.1 CURRENT_RESOURCE_GROUP

json_storage_size, json_type, json_unquote, json_valid, lower, md5, �→ reverse, tidb_shard, upper, vitess_hash • 这个只读变量用于显示创建表达式索引所允许使用的函数。 14.5.1.87 tidb_allow_mpp 从 v5.0 版本开始引入 • 作用域：SESSION | GLOBAL • JSON_UNQUOTE() • JSON_VALID() • LOWER() • MD5() • REVERSE() • TIDB_SHARD() • UPPER() • VITESS_HASH() 对于以上列表之外的函数，由于未完成充分测试，当前仍为实验特性，不建议在生产环境中使用。其他的表 达式例如运算符、CAST 和 CASE WHEN 也同样为实验特性，不建议在生产环境中使用。如果仍然希望使用，可 utc_timestamp | | uuid | | uuid_short | | uuid_to_bin | | validate_password_strength | | version | | vitess_hash | | week | | weekday | | weekofyear | | weight_string | | xor | | year | 3385 | yearweek

json_storage_size, json_type, json_unquote, json_valid, lower, md5, �→ reverse, tidb_shard, upper, vitess_hash • 这个只读变量用于显示创建表达式索引所允许使用的函数。 14.5.1.89 tidb_allow_mpp 从 v5.0 版本开始引入 • 作用域：SESSION | GLOBAL • JSON_UNQUOTE() • JSON_VALID() • LOWER() • MD5() • REVERSE() • TIDB_SHARD() • UPPER() • VITESS_HASH() 对于以上列表之外的函数，由于未完成充分测试，当前仍为实验特性，不建议在生产环境中使用。其他的表 达式例如运算符、CAST 和 CASE WHEN 也同样为实验特性，不建议在生产环境中使用。如果仍然希望使用，可 TIDB_SHARD 函数为前缀的表 达式索引。 TIDB_VERSION() 用于获取当前连接的 TiDB 服务器的版本以及构建 信息。 VITESS_HASH() 返回与 Vitess 的 HASH 函数兼容的数值的哈希值， 有助于从 Vitess 迁移至 TiDB。 14.12.4.22.1 CURRENT_RESOURCE_GROUP CURRENT_RESOURCE_GROUP()