diff --git a/src/Common/ThreadPool.cpp b/src/Common/ThreadPool.cpp
index a6cfec9521e7..e596aa154221 100644
--- a/src/Common/ThreadPool.cpp
+++ b/src/Common/ThreadPool.cpp
@@ -12,6 +12,8 @@
 #include <Poco/Util/Application.h>
 #include <Poco/Util/LayeredConfiguration.h>
 #include <base/demangle.h>
+#include <Common/StackTrace.h>
+#include <Common/logger_useful.h>
 
 namespace DB
 {
@@ -128,9 +130,12 @@ ThreadPoolImpl<Thread>::ThreadPoolImpl(
     , queue_size(queue_size_ ? std::max(queue_size_, max_threads) : 0 /* zero means the queue is unlimited */)
     , shutdown_on_exception(shutdown_on_exception_)
 {
-    // std::lock_guard lock(mutex);
-    // jobs.reserve(queue_size);
-    // while (threads.size() < std::min(max_threads, scheduled_jobs + (std::is_same_v<Thread, std::thread> ? min_free_threads : 1) ) )
+    std::lock_guard lock(mutex);
+    jobs.reserve(max_free_threads);
+    LOG_ERROR(&Poco::Logger::get("ThreadPoolImpl"),
+                  "ThreadPoolImpl constructor [Instance Address: {}]: max_threads = {}, max_free_threads = {}, queue_size = {}, StackTrace: {}",
+                  static_cast<void*>(this), max_threads, max_free_threads, queue_size, StackTrace().toString());
+    // while (threads.size() < max_free_threads)
     // {
     //     try
     //     {
@@ -285,7 +290,9 @@ ReturnType ThreadPoolImpl<Thread>::scheduleImpl(Job job, Priority priority, std:
         Stopwatch watch2;
         auto pred = [this] { return !queue_size || scheduled_jobs < queue_size || shutdown; };
 
-        if (wait_microseconds)  /// Check for optional. Condition is true if the optional is set and the value is zero.
+        /// if (wait_microseconds.has_value() && wait_microseconds.value() > 0)
+
+        if (wait_microseconds)  /// Check for optional. Condition is also true if the optional has value=0.
         {
             if (!job_finished.wait_for(lock, std::chrono::microseconds(*wait_microseconds), pred))
                 return on_error(fmt::format("no free thread (timeout={})", *wait_microseconds));
@@ -306,7 +313,7 @@ ReturnType ThreadPoolImpl<Thread>::scheduleImpl(Job job, Priority priority, std:
         /// Check if there are enough threads to process job.
         if (threads.size() < std::min(max_threads, scheduled_jobs + 1))
         {
-            // while (threads.size() < std::min(max_threads, scheduled_jobs + (std::is_same_v<Thread, std::thread> ? min_free_threads : 1) ) )
+            // while (threads.size() < std::min(max_threads, scheduled_jobs + 1) )
             // {
                 try
                 {
@@ -320,7 +327,7 @@ ReturnType ThreadPoolImpl<Thread>::scheduleImpl(Job job, Priority priority, std:
                 {
                     on_error("can not start new thread");
                 }
-            // }
+                // }
         }
 
         Stopwatch watch3;
@@ -393,6 +400,10 @@ ThreadPoolImpl<Thread>::~ThreadPoolImpl()
     /// Note: should not use logger from here,
     /// because it can be an instance of GlobalThreadPool that is a global variable
     /// and the destruction order of global variables is unspecified.
+    LOG_ERROR(&Poco::Logger::get("ThreadPoolImpl"),
+                  "ThreadPoolImpl destructor [Instance Address: {}]: threads.size() = {}",
+                  static_cast<void*>(this), threads.size());
+
 
     finalize();
     onDestroy();