Add enable_checkpointing control for checkpoint threads

Implemented an atomic flag to manage the state of checkpointing, ensuring that checkpoint threads are not redundantly initiated or terminated. This change adds a safety check in the `RunCheckPointThread` and `StopFlushThread` methods to prevent multiple threads from starting or stopping concurrently. Adjusted related configurations and tests to support and validate this new behavior.

src/common/bustub_instance.cpp

@@ -402,7 +402,9 @@ BustubInstance::~BustubInstance() {
   if (enable_logging) {
     log_manager_->StopFlushThread();
   }
-  checkpoint_manager_->StopFlushThread();
+  if (enable_checkpointing) {
+    checkpoint_manager_->StopFlushThread();
+  }
   delete execution_engine_;
   delete catalog_;
   delete checkpoint_manager_;

src/common/config.cpp

@@ -15,6 +15,7 @@
 namespace bustub {
 
 std::atomic<bool> enable_logging(false);
+std::atomic<bool> enable_checkpointing(false);
 
 std::chrono::duration<int64_t> log_timeout = std::chrono::seconds(1);
 std::chrono::duration<int64_t> checkpoint_timeout = std::chrono::seconds(2);

src/include/common/config.h

@@ -27,6 +27,7 @@ extern std::atomic<bool> enable_logging;
 /** If ENABLE_LOGGING is true, the log should be flushed to disk every LOG_TIMEOUT. */
 extern std::chrono::duration<int64_t> log_timeout;
 
+extern std::atomic<bool> enable_checkpointing;
 extern std::chrono::duration<int64_t> checkpoint_timeout;
 
 static constexpr int INVALID_PAGE_ID = -1;                                           // invalid page id

src/recovery/checkpoint_manager.cpp

@@ -32,6 +32,11 @@ void CheckpointManager::EndCheckpoint() {
 }
 
 void CheckpointManager::RunCheckPointThread() {
+  if (enable_checkpointing) {
+    return;
+  }
+
+  enable_checkpointing = true;
   checkpoint_thread_ = new std::thread([&] {
     while (true) {
       std::this_thread::sleep_for(checkpoint_timeout);
@@ -42,6 +47,7 @@ void CheckpointManager::RunCheckPointThread() {
 }
 
 void CheckpointManager::StopFlushThread() {
+  enable_checkpointing = false;
   checkpoint_thread_->join();
   delete checkpoint_thread_;
   checkpoint_thread_ = nullptr;

test/recovery/recovery_test.cpp

@@ -243,7 +243,7 @@ TEST_F(RecoveryTest, CheckpointTest) {
   auto val_1 = tuple.GetValue(&schema, 1);
 
   // set log time out very high so that flush doesn't happen before checkpoint is performed
-  log_timeout = std::chrono::seconds(3);
+  log_timeout = std::chrono::seconds(2);
 
   // insert a ton of tuples
   Transaction *txn1 = bustub_instance->txn_manager_->Begin();