Why does it take the ThreadPool 10+ seconds to shutdown when there is nothing running. #2450
Description
Expected behavior
ThreadPool's destructor should exist right away when there are no runnables anymore
Actual behavior
ThreadPool is in a self imposed 10-second holding pattern waiting for stuff that is already gone
The joinAll is immediatly satisfied, but the ThreadPool destructor doesn't let go until 10 seconds later.
Steps to reproduce the problem
#include "pch.h" // nothing in here
#include <iostream>
#include <chrono>
#include <thread>
#include "Poco/Runnable.h"
#include "Poco/Thread.h"
#include "Poco/ThreadPool.h"
using namespace std;
class Worker : public Poco::Runnable
{
static bool _shutDown;
public:
Worker()
{
}
void run()
{
thread::id this_id = this_thread::get_id();
cout << "Start. [Worker: tid:" << this_id << "]" << endl;
while (!_shutDown)
{
std::this_thread::sleep_for(std::chrono::milliseconds(250));
cout << "Working. [Worker: tid:" << this_id << "]" << endl;
}
cout << "Leaving. [Worker: tid:" << this_id << "]" << endl;
}
static void Initialize() {
_shutDown = false;
}
static void Shutdown() {
_shutDown = true;
}
};
bool Worker::_shutDown = false;
int main()
{
Worker::Initialize();
cout << "Hello World!\n";
Worker worker1; // create worker threads
Worker worker2;
Worker::Shutdown(); // workers will come up, and then immediatly be told to go away
Poco::ThreadPool::defaultPool().start(worker1);
Poco::ThreadPool::defaultPool().start(worker2);
Poco::ThreadPool::defaultPool().joinAll();
system("pause");
}
H:\github\ghstahl\poco.windows.visualstudio\src\x64\Debug>PocoThreadPoolPlay.exe
Hello World!
Start. [Worker: tid:56164]Start. [Worker: tid:68904]
Leaving. [Worker: tid:56164]
Leaving. [Worker: tid:68904]
Press any key to continue . . . < I press any key>
<waits here for 10 seconds when there is no reason to>
POCO version
Latest
Compiler and version
Microsoft Visual Studio Enterprise 2017
Version 15.8.2
VisualStudio.15.Release/15.8.2+28010.2016
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Version 4.7.03056
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Azure Data Lake Tools for Visual Studio 2.3.4000.4
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Operating system and version
Windows 10
Other relevant information
x64