topN executor refactored ♻️

AyoubKaz07 · Dec 10, 2023 · f06550f · f06550f
1 parent 1334cec
commit f06550f
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Showing 6 changed files with 39 additions and 64 deletions.
diff --git a/src/execution/topn_executor.cpp b/src/execution/topn_executor.cpp
@@ -1,33 +1,58 @@
 #include "execution/executors/topn_executor.h"
+#include <queue>
 
 namespace bustub {
 
 TopNExecutor::TopNExecutor(ExecutorContext *exec_ctx, const TopNPlanNode *plan,
                            std::unique_ptr<AbstractExecutor> &&child_executor)
-    : AbstractExecutor(exec_ctx),
-      plan_(plan),
-      child_executor_(std::move(child_executor)),
-      comparator_(this),      // Pass this TopNExecutor instance to the TupleComparator constructor
-      topNHeap_(comparator_)  // Pass the TupleComparator instance to the priority_queue constructor
-{}
+    : AbstractExecutor(exec_ctx), plan_(plan), child_executor_(std::move(child_executor)) {}
 
 void TopNExecutor::Init() {
+  // Comparator for the top-N heap
+  auto comparator = [this](const Tuple &t1, const Tuple &t2) -> bool {
+    for (const auto &[order_by_type, expr] : plan_->GetOrderBy()) {
+      if (order_by_type == OrderByType::ASC || order_by_type == OrderByType::DEFAULT) {
+        if (expr->Evaluate(&t1, child_executor_->GetOutputSchema())
+                .CompareLessThan(expr->Evaluate(&t2, child_executor_->GetOutputSchema())) == CmpBool::CmpTrue) {
+          return true;
+        } else if (expr->Evaluate(&t1, child_executor_->GetOutputSchema())
+                       .CompareGreaterThan(expr->Evaluate(&t2, child_executor_->GetOutputSchema())) ==
+                   CmpBool::CmpTrue) {
+          return false;
+        }
+      }
+      if (order_by_type == OrderByType::DESC) {
+        if (expr->Evaluate(&t1, child_executor_->GetOutputSchema())
+                .CompareLessThan(expr->Evaluate(&t2, child_executor_->GetOutputSchema())) == CmpBool::CmpTrue) {
+          return false;
+        } else if (expr->Evaluate(&t1, child_executor_->GetOutputSchema())
+                       .CompareGreaterThan(expr->Evaluate(&t2, child_executor_->GetOutputSchema())) ==
+                   CmpBool::CmpTrue) {
+          return true;
+        }
+      }
+    }
+    return false;
+  };
+
+  std::priority_queue<Tuple, std::vector<Tuple>, decltype(comparator)> topNHeap_(comparator);
+
   Tuple tuple;
   RID rid;
   child_executor_->Init();
   // Process each tuple from the child executor
   while (child_executor_->Next(&tuple, &rid)) {
     // Add the tuple to the top-N heap
-    this->topNHeap_.push(tuple);
+    topNHeap_.push(tuple);
 
     // Ensure the heap size doesn't exceed N
     while (topNHeap_.size() > plan_->GetN()) {
-      this->topNHeap_.pop();
+      topNHeap_.pop();
     }
   }
-  while (!(this->topNHeap_.empty())) {
+  while (!(topNHeap_.empty())) {
     sorted_tuples_.push_back(topNHeap_.top());
-    this->topNHeap_.pop();
+    topNHeap_.pop();
   }
 }
 

diff --git a/src/include/execution/executors/delete_executor.h b/src/include/execution/executors/delete_executor.h
@@ -13,9 +13,9 @@
 #pragma once
 
 #include <memory>
+#include <string>
 #include <utility>
 #include <vector>
-#include <string>
 
 #include "execution/executor_context.h"
 #include "execution/executors/abstract_executor.h"

diff --git a/src/include/execution/executors/insert_executor.h b/src/include/execution/executors/insert_executor.h
@@ -13,9 +13,9 @@
 #pragma once
 
 #include <memory>
+#include <string>
 #include <utility>
 #include <vector>
-#include <string>
 
 #include "execution/executor_context.h"
 #include "execution/executors/abstract_executor.h"

diff --git a/src/include/execution/executors/nested_loop_join_executor.h b/src/include/execution/executors/nested_loop_join_executor.h
@@ -13,8 +13,8 @@
 #pragma once
 
 #include <memory>
-#include <vector>
 #include <utility>
+#include <vector>
 
 #include "execution/executor_context.h"
 #include "execution/executors/abstract_executor.h"

diff --git a/src/include/execution/executors/seq_scan_executor.h b/src/include/execution/executors/seq_scan_executor.h
@@ -12,8 +12,8 @@
 
 #pragma once
 
-#include <vector>
 #include <memory>
+#include <vector>
 
 #include "execution/executor_context.h"
 #include "execution/executors/abstract_executor.h"

diff --git a/src/include/execution/executors/topn_executor.h b/src/include/execution/executors/topn_executor.h
@@ -24,15 +24,6 @@
 
 namespace bustub {
 
-class TopNExecutor;
-
-struct TupleComparator {
-  const TopNExecutor *executor_;  // Reference to the parent TopNExecutor instance
-
-  explicit TupleComparator(const TopNExecutor *executor) : executor_(executor) {}
-
-  bool operator()(const Tuple &t1, const Tuple &t2) const;
-};
 
 /**
  * The TopNExecutor executor executes a topn.
@@ -67,47 +58,6 @@ class TopNExecutor : public AbstractExecutor {
   /** The child executor used to retrieve tuples from */
   std::unique_ptr<AbstractExecutor> child_executor_;
 
-  // Custom comparator function for the priority queue
-  struct TupleComparator {
-    const TopNExecutor *executor_;  // Reference to the parent TopNExecutor instance
-
-    explicit TupleComparator(const TopNExecutor *executor) : executor_(executor) {}
-
-    bool operator()(const Tuple &t1, const Tuple &t2) const {
-      for (const auto &[order_by_type, expr] : executor_->plan_->GetOrderBy()) {
-        if (order_by_type == OrderByType::ASC || order_by_type == OrderByType::DEFAULT) {
-          if (expr->Evaluate(&t1, executor_->child_executor_->GetOutputSchema())
-                  .CompareLessThan(expr->Evaluate(&t2, executor_->child_executor_->GetOutputSchema())) ==
-              CmpBool::CmpTrue) {
-            return true;
-          } else if (expr->Evaluate(&t1, executor_->child_executor_->GetOutputSchema())
-                         .CompareGreaterThan(expr->Evaluate(&t2, executor_->child_executor_->GetOutputSchema())) ==
-                     CmpBool::CmpTrue) {
-            return false;
-          }
-        }
-        if (order_by_type == OrderByType::DESC) {
-          if (expr->Evaluate(&t1, executor_->child_executor_->GetOutputSchema())
-                  .CompareLessThan(expr->Evaluate(&t2, executor_->child_executor_->GetOutputSchema())) ==
-              CmpBool::CmpTrue) {
-            return false;
-          } else if (expr->Evaluate(&t1, executor_->child_executor_->GetOutputSchema())
-                         .CompareGreaterThan(expr->Evaluate(&t2, executor_->child_executor_->GetOutputSchema())) ==
-                     CmpBool::CmpTrue) {
-            return true;
-          }
-        }
-      }
-      return false;
-    }
-  };
-
-  /** Tuple comparator */
-  TupleComparator comparator_;
-
-  /** The topn heap */
-  std::priority_queue<Tuple, std::vector<Tuple>, TupleComparator> topNHeap_;
-
   /** Tuples result (stack)*/
   std::vector<Tuple> sorted_tuples_;
 };