feat: display logical plan after heuristic (#141)

It might be helpful to see what the plan looks like after the heuristics
phase. It might help us to identify things that are not handled in the
system and help us make design decisions forward on implementing rules.

Signed-off-by: Yuchen Liang <[email protected]>

Author: yliang412

optd-datafusion-bridge/src/lib.rs

@@ -233,6 +233,16 @@ impl OptdQueryPlanner {
 
         if optimizer.is_heuristic_enabled() {
             optd_rel = optimizer.heuristic_optimize(optd_rel);
+            if let Some(explains) = &mut explains {
+                explains.push(StringifiedPlan::new(
+                    PlanType::OptimizedLogicalPlan {
+                        optimizer_name: "optd-heuristic".to_string(),
+                    },
+                    PlanNode::from_rel_node(optd_rel.clone())
+                        .unwrap()
+                        .explain_to_string(None),
+                ))
+            }
         }
 
         let (group_id, optimized_rel, meta) = optimizer.cascades_optimize(optd_rel)?;

optd-sqlplannertest/src/lib.rs

@@ -163,6 +163,16 @@ impl DatafusionDBMS {
                         .map(|x| &x[1])
                         .unwrap()
                 )?;
+            } else if subtask == "logical_optd_heuristic" {
+                writeln!(
+                    r,
+                    "{}",
+                    result
+                        .iter()
+                        .find(|x| x[0] == "logical_plan after optd-heuristic")
+                        .map(|x| &x[1])
+                        .unwrap()
+                )?;
             } else if subtask == "logical_optd" {
                 writeln!(
                     r,