Backport #73081 to 24.3: Fix possible overestimate memory tracking

robot-clickhouse · robot-clickhouse · commit 4148baf6b95b · 2024-12-11T14:08:38.000Z
diff --git a/src/Common/ThreadStatus.cpp b/src/Common/ThreadStatus.cpp
@@ -203,8 +203,6 @@ bool ThreadStatus::isQueryCanceled() const
 
 ThreadStatus::~ThreadStatus()
 {
-    flushUntrackedMemory();
-
     /// It may cause segfault if query_context was destroyed, but was not detached
     auto query_context_ptr = query_context.lock();
     assert((!query_context_ptr && getQueryId().empty()) || (query_context_ptr && getQueryId() == query_context_ptr->getCurrentQueryId()));
@@ -215,6 +213,9 @@ ThreadStatus::~ThreadStatus()
 
     chassert(!check_current_thread_on_destruction || current_thread == this);
 
+    /// Flush untracked_memory **right before** switching the current_thread to avoid losing untracked_memory in deleter (detachFromGroup)
+    flushUntrackedMemory();
+
     /// Only change current_thread if it's currently being used by this ThreadStatus
     /// For example, PushingToViews chain creates and deletes ThreadStatus instances while running in the main query thread
     if (current_thread == this)
