Minor: display filter in HashJoin's tree explain (#17170)

Author: 2010YOUY01

datafusion/physical-plan/src/joins/hash_join.rs

@@ -716,7 +716,14 @@ impl DisplayAs for HashJoinExec {
                 if *self.join_type() != JoinType::Inner {
                     writeln!(f, "join_type={:?}", self.join_type)?;
                 }
-                writeln!(f, "on={on}")
+
+                writeln!(f, "on={on}")?;
+
+                if let Some(filter) = self.filter.as_ref() {
+                    writeln!(f, "filter={filter}")?;
+                }
+
+                Ok(())
             }
         }
     }

datafusion/physical-plan/src/joins/join_filter.rs

@@ -19,7 +19,7 @@ use crate::joins::utils::ColumnIndex;
 use arrow::datatypes::SchemaRef;
 use datafusion_common::JoinSide;
 use datafusion_physical_expr_common::physical_expr::PhysicalExpr;
-use std::sync::Arc;
+use std::{fmt::Display, sync::Arc};
 
 /// Filter applied before join output. Fields are crate-public to allow
 /// downstream implementations to experiment with custom joins.
@@ -33,6 +33,14 @@ pub struct JoinFilter {
     pub(crate) schema: SchemaRef,
 }
 
+/// For display in `EXPLAIN` plans, only expression with column names is needed,
+/// it output expresion like `(col1 + col2) = 0`
+impl Display for JoinFilter {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.expression.fmt_sql(f)
+    }
+}
+
 impl JoinFilter {
     /// Creates new JoinFilter
     pub fn new(

datafusion/sqllogictest/test_files/explain_tree.slt

@@ -287,7 +287,12 @@ physical_plan
 
 # 2 Joins
 query TT
-explain SELECT table1.string_col, table2.date_col FROM table1 JOIN table2 ON table1.int_col = table2.int_col;
+EXPLAIN SELECT table1.string_col, table2.date_col
+FROM table1 
+JOIN table2 
+ON 
+  (table1.int_col = table2.int_col)
+  AND (((table1.int_col + table2.int_col) % 2) = 0)
 ----
 physical_plan
 01)┌───────────────────────────┐
@@ -307,24 +312,28 @@ physical_plan
 15)┌─────────────┴─────────────┐
 16)│        HashJoinExec       │
 17)│    --------------------   │
-18)│            on:            ├──────────────┐
-19)│    (int_col = int_col)    │              │
-20)└─────────────┬─────────────┘              │
-21)┌─────────────┴─────────────┐┌─────────────┴─────────────┐
-22)│       DataSourceExec      ││      RepartitionExec      │
-23)│    --------------------   ││    --------------------   │
-24)│          files: 1         ││ partition_count(in->out): │
-25)│      format: parquet      ││           1 -> 4          │
-26)│                           ││                           │
-27)│                           ││    partitioning_scheme:   │
-28)│                           ││     RoundRobinBatch(4)    │
-29)└───────────────────────────┘└─────────────┬─────────────┘
-30)-----------------------------┌─────────────┴─────────────┐
-31)-----------------------------│       DataSourceExec      │
-32)-----------------------------│    --------------------   │
-33)-----------------------------│          files: 1         │
-34)-----------------------------│        format: csv        │
-35)-----------------------------└───────────────────────────┘
+18)│          filter:          │
+19)│ CAST(int_col + int_col AS │
+20)│       Int64) % 2 = 0      ├──────────────┐
+21)│                           │              │
+22)│            on:            │              │
+23)│    (int_col = int_col)    │              │
+24)└─────────────┬─────────────┘              │
+25)┌─────────────┴─────────────┐┌─────────────┴─────────────┐
+26)│       DataSourceExec      ││      RepartitionExec      │
+27)│    --------------------   ││    --------------------   │
+28)│          files: 1         ││ partition_count(in->out): │
+29)│      format: parquet      ││           1 -> 4          │
+30)│                           ││                           │
+31)│                           ││    partitioning_scheme:   │
+32)│                           ││     RoundRobinBatch(4)    │
+33)└───────────────────────────┘└─────────────┬─────────────┘
+34)-----------------------------┌─────────────┴─────────────┐
+35)-----------------------------│       DataSourceExec      │
+36)-----------------------------│    --------------------   │
+37)-----------------------------│          files: 1         │
+38)-----------------------------│        format: csv        │
+39)-----------------------------└───────────────────────────┘
 
 # 3 Joins
 query TT