Attempt to fix

dbms/src/Interpreters/ThreadStatusExt.cpp

@@ -156,17 +156,13 @@ void ThreadStatus::finalizePerformanceCounters()
 void ThreadStatus::initQueryProfiler()
 {
     /// query profilers are useless without trace collector
-    if (!global_context)
+    if (!global_context || !ext::Singleton<TraceCollector>::isInitialized())
         return;
 
     const auto & settings = query_context->getSettingsRef();
 
     try
     {
-        /// Force initialization of TraceCollector instance before setting signal handlers,
-        /// because the constructor is not async-signal-safe.
-        ext::Singleton<TraceCollector> initialize __attribute__((unused));
-
         if (settings.query_profiler_real_time_period_ns > 0)
             query_profiler_real = std::make_unique<QueryProfilerReal>(thread_id,
                 /* period */ static_cast<UInt32>(settings.query_profiler_real_time_period_ns));

libs/libcommon/include/ext/singleton.h

@@ -1,33 +1,18 @@
 #pragma once
 
 #include <memory>
-#include <type_traits>
 
 namespace ext {
 
-template <class T, typename DefaultConstructable = void>
-class Singleton;
-
-/// For default-constructable type we don't need to implement |create()|
-/// and may use "arrow" operator immediately.
 template <class T>
-class Singleton<T, std::enable_if_t<std::is_default_constructible_v<T>>>
+class Singleton
 {
 public:
-    T * operator->()
+    Singleton()
     {
-        static T instance;
-        return &instance;
+        if (!instance)
+            instance.reset(new T);
     }
-};
-
-/// For custom-constructed type we have to construct |Singleton| object with non-default constructor once
-/// before any use of "arrow" operator.
-template <class T>
-class Singleton<T, std::enable_if_t<!std::is_default_constructible_v<T>>>
-{
-public:
-    Singleton() = default;
 
     template <typename ... Args>
     Singleton(const Args & ... args)
@@ -41,6 +26,10 @@ public:
         return instance.get();
     }
 
+    static bool isInitialized() {
+        return !!instance;
+    }
+
 private:
     inline static std::unique_ptr<T> instance{};
 };