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system-variables: write the version info of tidb_read_consistency in Chinese #15201

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Oct 16, 2023
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system-variables: write the version info of tidb_read_consistency in Chinese #15201

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2 changes: 1 addition & 1 deletion system-variables.md
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Expand Up @@ -3985,7 +3985,7 @@ EXPLAIN FORMAT='brief' SELECT COUNT(1) FROM t WHERE a = 1 AND b IS NOT NULL;
- 该变量用于优化时间戳的获取，适用于悲观事务 `READ-COMMITTED` 隔离级别下点写冲突较少的场景。开启此变量可以避免点写语句获取全局时间戳带来的延迟和开销。目前该变量适用的点写语句包括 `UPDATE`、`DELETE`、`SELECT ...... FOR UPDATE` 三种类型。点写语句是指将主键或者唯一键作为过滤条件且最终执行算子包含 `POINT-GET` 的写语句。
- 如果点写冲突较为严重，开启此变量会增加额外开销和延迟，造成性能回退。更详细的说明，请参考[读已提交隔离级别 (Read Committed) 文档](/transaction-isolation-levels.md#读已提交隔离级别-read-committed)。

### `tidb_read_consistency` <span class="version-mark">New in v5.4.0</span>
### `tidb_read_consistency` <span class="version-mark">从 v5.4.0 版本开始引入</span>

- 作用域：SESSION
- 是否受 Hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value) 控制：是
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