Implement tree explain for SortExec (#15077)

* Implement `tree` explain for `SortExec`

* fix issues

---------

Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

Author: irenjj

datafusion/physical-plan/src/sorts/sort.rs

@@ -1005,10 +1005,15 @@ impl DisplayAs for SortExec {
                     None => write!(f, "SortExec: expr=[{}], preserve_partitioning=[{preserve_partitioning}]", self.expr),
                 }
             }
-            DisplayFormatType::TreeRender => {
-                // TODO: collect info
-                write!(f, "")
-            }
+            DisplayFormatType::TreeRender => match self.fetch {
+                Some(fetch) => {
+                    writeln!(f, "limit={fetch}")?;
+                    writeln!(f, "sort keys=[{}]", self.expr)
+                }
+                None => {
+                    writeln!(f, "sort keys=[{}]", self.expr)
+                }
+            },
         }
     }
 }
@@ -1225,13 +1230,9 @@ mod tests {
     impl DisplayAs for SortedUnboundedExec {
         fn fmt_as(&self, t: DisplayFormatType, f: &mut Formatter) -> fmt::Result {
             match t {
-                DisplayFormatType::Default | DisplayFormatType::Verbose => {
-                    write!(f, "UnboundableExec",).unwrap()
-                }
-                DisplayFormatType::TreeRender => {
-                    // TODO: collect info
-                    write!(f, "").unwrap()
-                }
+                DisplayFormatType::Default
+                | DisplayFormatType::Verbose
+                | DisplayFormatType::TreeRender => write!(f, "UnboundableExec",).unwrap(),
             }
             Ok(())
         }

datafusion/sqllogictest/test_files/explain_tree.slt

@@ -539,6 +539,52 @@ physical_plan
 17)│       format: arrow       │
 18)└───────────────────────────┘
 
+# Query for sort.
+query TT
+explain SELECT * FROM table1 ORDER BY string_col;
+----
+logical_plan
+01)Sort: table1.string_col ASC NULLS LAST
+02)--TableScan: table1 projection=[int_col, string_col, bigint_col, date_col]
+physical_plan
+01)┌───────────────────────────┐
+02)│          SortExec         │
+03)│    --------------------   │
+04)│         sort keys:        │
+05)│  [string_col@1 ASC NULLS  │
+06)│            LAST]          │
+07)└─────────────┬─────────────┘
+08)┌─────────────┴─────────────┐
+09)│       DataSourceExec      │
+10)│    --------------------   │
+11)│          files: 1         │
+12)│        format: csv        │
+13)└───────────────────────────┘
+
+# Query for sort with limit.
+query TT
+explain SELECT * FROM table1 ORDER BY string_col LIMIT 1;
+----
+logical_plan
+01)Sort: table1.string_col ASC NULLS LAST, fetch=1
+02)--TableScan: table1 projection=[int_col, string_col, bigint_col, date_col]
+physical_plan
+01)┌───────────────────────────┐
+02)│          SortExec         │
+03)│    --------------------   │
+04)│          limit: 1         │
+05)│                           │
+06)│         sort keys:        │
+07)│  [string_col@1 ASC NULLS  │
+08)│            LAST]          │
+09)└─────────────┬─────────────┘
+10)┌─────────────┴─────────────┐
+11)│       DataSourceExec      │
+12)│    --------------------   │
+13)│          files: 1         │
+14)│        format: csv        │
+15)└───────────────────────────┘
+
 # Query with projection on csv
 query TT
 explain SELECT int_col, bigint_col, int_col+bigint_col AS sum_col FROM table1;
@@ -629,8 +675,6 @@ physical_plan
 18)│          rows: 1          │
 19)└───────────────────────────┘
 
-
-
 # Query with projection on json
 query TT
 explain SELECT int_col, bigint_col, int_col+bigint_col AS sum_col FROM table4;