#include <QtSql>
#include <QtCore>
#include <QtConcurrent>

struct Cfg { QString drv, qname, host; int port; QString name, user, pass; };


void createDestroyDb(const Cfg& c) {
	bool ok = false; 
	QSqlDatabase d;
	for (;;) {
		d = QSqlDatabase::addDatabase(c.drv, c.qname); 
		if (!d.isValid()) 
			break;
		d.setHostName(c.host); 
		d.setPort(c.port); 
		d.setDatabaseName(c.name);
		d.setUserName(c.user); 
		d.setPassword(c.pass);
		{ /*static QMutex m; QMutexLocker l(&m);*/
			ok = d.open(); 
		}
		break;
	} // The QMutex hack suppresses the bug.
	if (!ok) 
		qWarning().noquote() << d.lastError().text(); 
	d = {}; 
	QSqlDatabase::removeDatabase(c.qname);
}


void f() {
	std::vector<QString> v;
	for (int i = 0; i < 1000; ++i) {
		v.push_back("db" + QString::number(i));
	}
	QtConcurrent::blockingMap(v, [](const QString& s)
		{ createDestroyDb({ "QPSQL", s, "wronghost", 5432, "db", "user", "pass" }); }
	);
	qInfo("No crash happened.");
}


int main(int ac, char* av[]) {
	qSetMessagePattern("[%{if-warning} - - - WARN %{endif}%{time HHmmss.zzz} %{file}:%{line} %{function} %{threadid}] %{message}");
	QCoreApplication app(ac, av); QTimer::singleShot(1000, [&] { f(); app.quit(); }); return app.exec();
}