value from 500ms to 100ms after op- timizing the algo- rithm to improve the sensi- tivity of slow node de- tection. 46 Configuration file Configuration parame- ter Change type Description TiKV raftstore version, it is recommended to use the feature in production environments in a later LTS version. • N: the feature is not supported. • E: the feature is not GA yet (experimental) and you need to be aware Y Y Y Y Y Y Y Y Character sets and collations 1 Y Y Y Y Y Y Y Y Y Y User-level lock Y Y Y Y N N N N N N 2.3.2 Indexing and constraints Indexing and constraints 7.5 7.1 6.5 6.1 5.4 5.3 5.2 5.1 5.0 4

that TiDB uses the value of the config- uration item txn- �→ entry �→ - �→ size �→ - �→ limit �→ by de- fault. When this vari- able is set to a non- zero value, txn- �→ entry �→ - �→ size �→ - �→ limit version, it is recommended to use the feature in production environments in a later LTS version. • N: the feature is not supported. • E: the feature is not GA yet (experimental) and you need to be aware Y Y Y Y Y Y Character sets and collations 1 Y Y Y Y Y Y Y Y Y Y Y User-level lock Y Y Y Y Y N N N N N N 2.3.2 Indexing and constraints Indexing and constraints 7.6 7.5 7.1 6.5 6.1 5.4 5.3 5.2 5.1 5

depre- cated. Its value will be fixed to the default value ON, that is, global index is en- abled by de- fault. You only need to add the key- word GLOBAL to the corre- spond- ing column when execut- ing cated. Its value will be fixed to the default value ON, that is, list parti- tioning is en- abled by de- fault. 50 Variable name Change type Description tidb_ �→ enable �→ _ �→ table �→ _ �→ partition cated. Its value will be fixed to the default value ON, that is, table parti- tioning is en- abled by de- fault. tidb_ �→ analyze �→ _ �→ partition �→ _ �→ concurrency �→ Modified Changes the value range

depre- cated. Its value will be fixed to the default value ON, that is, global index is en- abled by de- fault. You only need to add the key- word GLOBAL to the corre- spond- ing column when execut- ing cated. Its value will be fixed to the default value ON, that is, list parti- tioning is en- abled by de- fault. 55 Variable name Change type Description tidb_ �→ enable �→ _ �→ table �→ _ �→ partition cated. Its value will be fixed to the default value ON, that is, table parti- tioning is en- abled by de- fault. tidb_ �→ analyze �→ _ �→ partition �→ _ �→ concurrency �→ Modified Changes the value range

default value from OFF to ON. This means that Dis- tributed eXecu- tion Frame- work (DXF) is en- abled by de- fault, which fully utilizes the re- sources of the TiDB cluster and greatly im- proves the perfor- the conflict.strategy parameter. The duplicate-resolution parameter for the old version of conflict de- tection will be removed in a future release. 51 2.2.4 Improvements • TiDB • Improve the MySQL version, it is recommended to use the feature in production environments in a later LTS version. • N: the feature is not supported. • E: the feature is not GA yet (experimental) and you need to be aware

the conflict.strategy parameter. The duplicate-resolution parameter for the old version of conflict de- tection will be removed in a future release. • It is planned to redesign the auto-evolution of execution race in case of remote reads #8685 @solotzg • Fix the issue that the CAST(AS JSON) function does not de-duplicate the JSON object key #8712 @SeaRise 83 • Fix the issue that the ENUM column might cause version, it is recommended to use the feature in production environments in a later LTS version. • N: the feature is not supported. • E: the feature is not GA yet (experimental) and you need to be aware

in future versions: • Starting from v8.0.0, TiDB Lightning deprecates the old version of conflict de- tection strategy for the physical import mode, and enables you to control the conflict detection strategy version, it is recommended to use the feature in production environments in a later LTS version. • N: the feature is not supported. • E: the feature is not GA yet (experimental) and you need to be aware Y Y Y Y Y Character sets and collations 1 Y Y Y Y Y Y Y Y Y Y Y User-level lock Y Y Y Y Y Y Y N N N N 2.3.2 Indexing and constraints Indexing and constraints 8.3 8.2 8.1 7.5 7.1 6.5 6.1 5.4 5.3 5.2

concurrency and import performance, you need to explicitly specify terminator. The values can be \r, \n or \r\n. Failure to specify a line terminator might result in an exception when parsing the CSV file data need to explicitly specify the line terminator LINES_ �→ TERMINATED_BY. The values can be \r, \n or \r\n. Failure to specify a line terminator might result in an exception when parsing the CSV file data in future versions: • Starting from v8.0.0, TiDB Lightning deprecates the old version of conflict de- tection strategy for the physical import mode, and enables you to control the conflict detection strategy

tests, mean- ing that the sup- port of Outer Join for the Join Re- order algo- rithm is en- abled by de- fault. 45 Variable name Change type Description tidb_cost_model_version �→ Modified Changes the tests, mean- ing that Cost Model Version 2 is used for index selec- tion and op- erator selec- tion by de- fault. 46 Variable name Change type Description tidb_enable_gc_aware_memory_track �→ Modified value from OFF to ON after further tests, mean- ing that the meta- data lock feature is en- abled by de- fault. 48 Variable name Change type Description tidb_enable_tiflash_read_for_write_stmt �→ Modified

default value from OFF to ON. This means that Dis- tributed eXecu- tion Frame- work (DXF) is en- abled by de- fault, which fully utilizes the re- sources of the TiDB cluster and greatly im- proves the perfor- the conflict.strategy parameter. The duplicate-resolution parameter for the old version of conflict de- tection will be removed in a future release. 2.2.4 Improvements • TiDB • Improve the MySQL compatibility version, it is recommended to use the feature in production environments in a later LTS version. • N: the feature is not supported. • E: the feature is not GA yet (experimental) and you need to be aware