diff --git a/presto-native-execution/presto_cpp/main/QueryContextManager.cpp b/presto-native-execution/presto_cpp/main/QueryContextManager.cpp
index 3598603c300eb..95908e6903995 100644
--- a/presto-native-execution/presto_cpp/main/QueryContextManager.cpp
+++ b/presto-native-execution/presto_cpp/main/QueryContextManager.cpp
@@ -11,15 +11,16 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 #include "presto_cpp/main/QueryContextManager.h"
-#include <folly/executors/IOThreadPoolExecutor.h>
 #include "presto_cpp/main/PrestoToVeloxQueryConfig.h"
 #include "presto_cpp/main/SessionProperties.h"
 #include "presto_cpp/main/common/Configs.h"
+
 #include "velox/connectors/hive/HiveConfig.h"
 #include "velox/core/QueryConfig.h"
 
+#include <folly/executors/IOThreadPoolExecutor.h>
+
 using namespace facebook::velox;
 
 using facebook::presto::protocol::QueryId;
@@ -60,8 +61,11 @@ std::shared_ptr<velox::core::QueryCtx> QueryContextCache::insert(
     evict();
   }
   queryIds_.push_front(queryId);
-  queryCtxs_[queryId] = {
-      folly::to_weak_ptr(queryCtx), queryIds_.begin(), false};
+  queryCtxs_.insert(
+      {queryId,
+       {.queryCtx = folly::to_weak_ptr(queryCtx),
+        .idListIterator = queryIds_.begin(),
+        .hasStartedTasks = false}});
   return queryCtx;
 }
 
@@ -83,11 +87,11 @@ void QueryContextCache::setTasksStarted(const protocol::QueryId& queryId) {
 
 void QueryContextCache::evict() {
   // Evict least recently used queryCtx if it is not referenced elsewhere.
-  for (auto victim = queryIds_.end(); victim != queryIds_.begin();) {
-    --victim;
-    if (!queryCtxs_[*victim].queryCtx.lock()) {
-      queryCtxs_.erase(*victim);
-      queryIds_.erase(victim);
+  for (auto victim = queryIds_.rbegin(); victim != queryIds_.rend(); ++victim) {
+    auto iter = queryCtxs_.find(*victim);
+    if (iter != queryCtxs_.end() && !iter->second.queryCtx.lock()) {
+      queryCtxs_.erase(iter);
+      queryIds_.erase(std::next(victim).base());
       return;
     }
   }
diff --git a/presto-native-execution/presto_cpp/main/QueryContextManager.h b/presto-native-execution/presto_cpp/main/QueryContextManager.h
index 3a07b73c36335..70faa88b86381 100644
--- a/presto-native-execution/presto_cpp/main/QueryContextManager.h
+++ b/presto-native-execution/presto_cpp/main/QueryContextManager.h
@@ -35,7 +35,7 @@ class QueryContextCache {
   };
   using QueryCtxMap = std::unordered_map<protocol::QueryId, QueryCtxCacheValue>;
 
-  QueryContextCache(size_t initial_capacity = kInitialCapacity)
+  explicit QueryContextCache(size_t initial_capacity = kInitialCapacity)
       : capacity_(initial_capacity) {}
 
   size_t capacity() const {
diff --git a/presto-native-execution/presto_cpp/main/TaskManager.cpp b/presto-native-execution/presto_cpp/main/TaskManager.cpp
index 257841d115dae..82a50ceb11194 100644
--- a/presto-native-execution/presto_cpp/main/TaskManager.cpp
+++ b/presto-native-execution/presto_cpp/main/TaskManager.cpp
@@ -354,11 +354,14 @@ void enqueueTask(
 TaskManager::TaskManager(
     folly::Executor* driverExecutor,
     folly::Executor* httpSrvCpuExecutor,
-    folly::Executor* spillerExecutor)
+    folly::Executor* spillerExecutor,
+    std::unique_ptr<QueryContextManager> queryContextManager)
     : queryContextManager_(
-          std::make_unique<QueryContextManager>(
-              driverExecutor,
-              spillerExecutor)),
+          queryContextManager == nullptr
+              ? std::make_unique<QueryContextManager>(
+                    driverExecutor,
+                    spillerExecutor)
+              : std::move(queryContextManager)),
       bufferManager_(velox::exec::OutputBufferManager::getInstanceRef()),
       httpSrvCpuExecutor_(httpSrvCpuExecutor),
       lastNotOverloadedTimeInSecs_(velox::getCurrentTimeSec()) {
diff --git a/presto-native-execution/presto_cpp/main/TaskManager.h b/presto-native-execution/presto_cpp/main/TaskManager.h
index 6d0fac7af8396..8b0926b044d46 100644
--- a/presto-native-execution/presto_cpp/main/TaskManager.h
+++ b/presto-native-execution/presto_cpp/main/TaskManager.h
@@ -32,10 +32,23 @@ class TaskManager {
   TaskManager(
       folly::Executor* driverExecutor,
       folly::Executor* httpSrvExecutor,
-      folly::Executor* spillerExecutor);
+      folly::Executor* spillerExecutor,
+      std::unique_ptr<QueryContextManager> queryContextManager = nullptr);
 
   virtual ~TaskManager() = default;
 
+  /// Always returns tuple of non-empty string containing the spill directory
+  /// and the date string directory, which is parent directory of task spill
+  /// directory.
+  static std::tuple<std::string, std::string> buildTaskSpillDirectoryPath(
+      const std::string& baseSpillPath,
+      const std::string& nodeIp,
+      const std::string& nodeId,
+      const std::string& queryId,
+      const protocol::TaskId& taskId,
+      bool includeNodeInSpillPath);
+
+ protected:
   /// Invoked by Presto server shutdown to wait for all the tasks to complete
   /// and cleanup the completed tasks.
   void shutdown();
@@ -166,17 +179,6 @@ class TaskManager {
       std::vector<std::string>& deadlockTasks,
       std::vector<velox::exec::Task::OpCallInfo>& stuckOpCalls) const;
 
-  /// Always returns tuple of non-empty string containing the spill directory
-  /// and the date string directory, which is parent directory of task spill
-  /// directory.
-  static std::tuple<std::string, std::string> buildTaskSpillDirectoryPath(
-      const std::string& baseSpillPath,
-      const std::string& nodeIp,
-      const std::string& nodeId,
-      const std::string& queryId,
-      const protocol::TaskId& taskId,
-      bool includeNodeInSpillPath);
-
   /// Presto Server can notify the Task Manager that the former is overloaded,
   /// so the Task Manager can optionally change Task admission algorithm.
   void setServerOverloaded(bool serverOverloaded);