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*: update the row count display of probe side of IndexJoin and Apply #10864

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*: update the row count display of probe side of IndexJoin and Apply #10864

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56 changes: 28 additions & 28 deletions correlated-subquery-optimization.md
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Original file line number Diff line number Diff line change
Expand Up @@ -57,20 +57,20 @@ explain select * from t1 where t1.a < (select /*+ NO_DECORRELATE() */ sum(t2.a)
```

```sql
+----------------------------------------+----------+-----------+------------------------+--------------------------------------------------------------------------------------+
| id | estRows | task | access object | operator info |
+----------------------------------------+----------+-----------+------------------------+--------------------------------------------------------------------------------------+
| Projection_10 | 10000.00 | root | | test.t1.a, test.t1.b |
| └─Apply_12 | 10000.00 | root | | CARTESIAN inner join, other cond:lt(cast(test.t1.a, decimal(10,0) BINARY), Column#7) |
| ├─TableReader_14(Build) | 10000.00 | root | | data:TableFullScan_13 |
| │ └─TableFullScan_13 | 10000.00 | cop[tikv] | table:t1 | keep order:false, stats:pseudo |
| └─MaxOneRow_15(Probe) | 1.00 | root | | |
| └─HashAgg_27 | 1.00 | root | | funcs:sum(Column#10)->Column#7 |
| └─IndexLookUp_28 | 1.00 | root | | |
| ├─IndexRangeScan_25(Build) | 10.00 | cop[tikv] | table:t2, index:idx(b) | range: decided by [eq(test.t2.b, test.t1.b)], keep order:false, stats:pseudo |
| └─HashAgg_17(Probe) | 1.00 | cop[tikv] | | funcs:sum(test.t2.a)->Column#10 |
| └─TableRowIDScan_26 | 10.00 | cop[tikv] | table:t2 | keep order:false, stats:pseudo |
+----------------------------------------+----------+-----------+------------------------+--------------------------------------------------------------------------------------+
+------------------------------------------+-----------+-----------+------------------------+--------------------------------------------------------------------------------------+
| id | estRows | task | access object | operator info |
+------------------------------------------+-----------+-----------+------------------------+--------------------------------------------------------------------------------------+
| Projection_10 | 10000.00 | root | | test.t1.a, test.t1.b |
| └─Apply_12 | 10000.00 | root | | CARTESIAN inner join, other cond:lt(cast(test.t1.a, decimal(10,0) BINARY), Column#7) |
| ├─TableReader_14(Build) | 10000.00 | root | | data:TableFullScan_13 |
| │ └─TableFullScan_13 | 10000.00 | cop[tikv] | table:t1 | keep order:false, stats:pseudo |
| └─MaxOneRow_15(Probe) | 10000.00 | root | | |
| └─StreamAgg_20 | 10000.00 | root | | funcs:sum(Column#14)->Column#7 |
| └─Projection_45 | 100000.00 | root | | cast(test.t2.a, decimal(10,0) BINARY)->Column#14 |
| └─IndexLookUp_44 | 100000.00 | root | | |
| ├─IndexRangeScan_42(Build) | 100000.00 | cop[tikv] | table:t2, index:idx(b) | range: decided by [eq(test.t2.b, test.t1.b)], keep order:false, stats:pseudo |
| └─TableRowIDScan_43(Probe) | 100000.00 | cop[tikv] | table:t2 | keep order:false, stats:pseudo |
+------------------------------------------+-----------+-----------+------------------------+--------------------------------------------------------------------------------------+
```

Disabling the decorrelation rule can also achieve the same effect:
Expand All @@ -84,20 +84,20 @@ explain select * from t1 where t1.a < (select sum(t2.a) from t2 where t2.b = t1.
```

```sql
+----------------------------------------+----------+-----------+------------------------+--------------------------------------------------------------------------------------+
| id | estRows | task | access object | operator info |
+----------------------------------------+----------+-----------+------------------------+--------------------------------------------------------------------------------------+
| Projection_10 | 10000.00 | root | | test.t1.a, test.t1.b |
| └─Apply_12 | 10000.00 | root | | CARTESIAN inner join, other cond:lt(cast(test.t1.a, decimal(10,0) BINARY), Column#7) |
| ├─TableReader_14(Build) | 10000.00 | root | | data:TableFullScan_13 |
| │ └─TableFullScan_13 | 10000.00 | cop[tikv] | table:t1 | keep order:false, stats:pseudo |
| └─MaxOneRow_15(Probe) | 1.00 | root | | |
| └─HashAgg_27 | 1.00 | root | | funcs:sum(Column#10)->Column#7 |
| └─IndexLookUp_28 | 1.00 | root | | |
| ├─IndexRangeScan_25(Build) | 10.00 | cop[tikv] | table:t2, index:idx(b) | range: decided by [eq(test.t2.b, test.t1.b)], keep order:false, stats:pseudo |
| └─HashAgg_17(Probe) | 1.00 | cop[tikv] | | funcs:sum(test.t2.a)->Column#10 |
| └─TableRowIDScan_26 | 10.00 | cop[tikv] | table:t2 | keep order:false, stats:pseudo |
+----------------------------------------+----------+-----------+------------------------+--------------------------------------------------------------------------------------+
+------------------------------------------+-----------+-----------+------------------------+--------------------------------------------------------------------------------------+
| id | estRows | task | access object | operator info |
+------------------------------------------+-----------+-----------+------------------------+--------------------------------------------------------------------------------------+
| Projection_10 | 10000.00 | root | | test.t1.a, test.t1.b |
| └─Apply_12 | 10000.00 | root | | CARTESIAN inner join, other cond:lt(cast(test.t1.a, decimal(10,0) BINARY), Column#7) |
| ├─TableReader_14(Build) | 10000.00 | root | | data:TableFullScan_13 |
| │ └─TableFullScan_13 | 10000.00 | cop[tikv] | table:t1 | keep order:false, stats:pseudo |
| └─MaxOneRow_15(Probe) | 10000.00 | root | | |
| └─StreamAgg_20 | 10000.00 | root | | funcs:sum(Column#14)->Column#7 |
| └─Projection_45 | 100000.00 | root | | cast(test.t2.a, decimal(10,0) BINARY)->Column#14 |
| └─IndexLookUp_44 | 100000.00 | root | | |
| ├─IndexRangeScan_42(Build) | 100000.00 | cop[tikv] | table:t2, index:idx(b) | range: decided by [eq(test.t2.b, test.t1.b)], keep order:false, stats:pseudo |
| └─TableRowIDScan_43(Probe) | 100000.00 | cop[tikv] | table:t2 | keep order:false, stats:pseudo |
+------------------------------------------+-----------+-----------+------------------------+--------------------------------------------------------------------------------------+
```

After disabling the subquery decorrelation rule, you can see `range: decided by [eq(test.t2.b, test.t1.b)]` in `operator info` of `IndexRangeScan_25(Build)`. It means that the decorrelation of correlated subquery is not performed and TiDB uses the index range query.
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