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fix the operator info (#15393) #15402

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Nov 9, 2023
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fix the operator info (#15393) #15402

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2 changes: 1 addition & 1 deletion correlated-subquery-optimization.md
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Expand Up @@ -100,4 +100,4 @@ explain select * from t1 where t1.a < (select sum(t2.a) from t2 where t2.b = t1.
+------------------------------------------+-----------+-----------+------------------------+--------------------------------------------------------------------------------------+
```

在执行了关闭关联规则的语句后，可以在 `IndexRangeScan_25(Build)` 的 `operator info` 中看到 `range: decided by [eq(test.t2.b, test.t1.b)]`。这部分信息就是关联依赖未被解除时，TiDB 使用关联条件进行索引范围查询的显示结果。
在执行了关闭关联规则的语句后，可以在 `IndexRangeScan_42(Build)` 的 `operator info` 中看到 `range: decided by [eq(test.t2.b, test.t1.b)]`。这部分信息就是关联依赖未被解除时，TiDB 使用关联条件进行索引范围查询的显示结果。
2 changes: 1 addition & 1 deletion explain-subqueries.md
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Expand Up @@ -68,7 +68,7 @@ EXPLAIN SELECT * FROM t1 WHERE id IN (SELECT t1_id FROM t2);

```

由上述查询结果可知，TiDB 通过索引连接操作 `| IndexJoin_14` 将子查询做了连接转化。该执行计划首先在 TiKV 侧通过索引扫描算子 `└─IndexFullScan_31` 读取 `t2.t1_id` 列的值，然后由 `└─StreamAgg_39` 算子的部分任务在 TiKV 中对 `t1_id` 值进行去重，然后采用 `├─StreamAgg_49(Build)` 算子的部分任务在 TiDB 中对 `t1_id` 值再次进行去重，去重操作由聚合函数 `firstrow(test.t2.t1_id)` 执行；之后将操作结果与 `t1` 表的主键相连接，连接条件是 `eq(test.t1.id, test.t2.t1_id)`。
由上述查询结果可知，TiDB 通过索引连接操作 `IndexJoin_15` 将子查询做了连接转化。该执行计划首先在 TiKV 侧通过索引扫描算子 `└─IndexFullScan_26` 读取 `t2.t1_id` 列的值，然后由 `└─StreamAgg_34` 算子的部分任务在 TiKV 中对 `t1_id` 值进行去重，然后采用 `├─StreamAgg_44(Build)` 算子的部分任务在 TiDB 中对 `t1_id` 值再次进行去重，去重操作由聚合函数 `firstrow(test.t2.t1_id)` 执行；之后将操作结果与 `t1` 表的主键相连接，连接条件是 `eq(test.t1.id, test.t2.t1_id)`。

## Inner join（有 `UNIQUE` 约束的子查询）

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