From: Gunnar Beutner <gunnar.beutner@netways.de>
Date: Tue, 19 Feb 2013 22:02:08 +0000 (+0100)
Subject: Fine-grained locks (WIP, Part 6).
X-Git-Tag: v0.0.2~376
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=997ca3a77a35d52ed2f42ed593fb502ac33a8d40;p=icinga2

Fine-grained locks (WIP, Part 6).
---

diff --git a/components/checker/checkercomponent.cpp b/components/checker/checkercomponent.cpp
index dbc8617dc..e72566ace 100644
--- a/components/checker/checkercomponent.cpp
+++ b/components/checker/checkercomponent.cpp
@@ -33,10 +33,10 @@ void CheckerComponent::Start(void)
 
 	Service::OnCheckerChanged.connect(bind(&CheckerComponent::CheckerChangedHandler, this, _1));
 	Service::OnNextCheckChanged.connect(bind(&CheckerComponent::NextCheckChangedHandler, this, _1));
-	DynamicObject::OnUnregistered.connect(bind(&CheckerComponent::ObjectRemovedHandler, this, _1));
 
-	boost::thread thread(boost::bind(&CheckerComponent::CheckThreadProc, this));
-	thread.detach();
+	m_Stopped = false;
+
+	m_Thread = thread(boost::bind(&CheckerComponent::CheckThreadProc, this));
 
 	m_ResultTimer = boost::make_shared<Timer>();
 	m_ResultTimer->SetInterval(5);
@@ -47,6 +47,14 @@ void CheckerComponent::Start(void)
 void CheckerComponent::Stop(void)
 {
 	m_Endpoint->Unregister();
+
+	{
+		boost::mutex::scoped_lock lock(m_Mutex);
+		m_Stopped = true;
+		m_CV.notify_all();
+	}
+
+	m_Thread.join();
 }
 
 void CheckerComponent::CheckThreadProc(void)
@@ -60,9 +68,12 @@ void CheckerComponent::CheckThreadProc(void)
 			typedef nth_index<ServiceSet, 1>::type CheckTimeView;
 			CheckTimeView& idx = boost::get<1>(m_IdleServices);
 
-			while (idx.begin() == idx.end())
+			while (idx.begin() == idx.end() && !m_Stopped)
 				m_CV.wait(lock);
 
+			if (m_Stopped)
+				break;
+
 			CheckTimeView::iterator it = idx.begin();
 			service = it->lock();
 
@@ -85,7 +96,8 @@ void CheckerComponent::CheckThreadProc(void)
 
 			/* Wait for the next check. */
 			boost::mutex::scoped_lock lock(m_Mutex);
-			m_CV.timed_wait(lock, boost::posix_time::milliseconds(wait * 1000));
+			if (!m_Stopped)
+				m_CV.timed_wait(lock, boost::posix_time::milliseconds(wait * 1000));
 
 			continue;
 		}
@@ -216,19 +228,3 @@ void CheckerComponent::NextCheckChangedHandler(const Service::Ptr& service)
 	}
 }
 
-void CheckerComponent::ObjectRemovedHandler(const DynamicObject::Ptr& object)
-{
-	Service::Ptr service = dynamic_pointer_cast<Service>(object);
-
-	/* ignore it if the removed object is not a service */
-	if (!service)
-		return;
-
-	{
-		boost::mutex::scoped_lock lock(m_Mutex);
-
-		m_IdleServices.erase(service);
-		m_PendingServices.erase(service);
-		m_CV.notify_all();
-	}
-}
diff --git a/components/checker/checkercomponent.h b/components/checker/checkercomponent.h
index 01c5a4191..f4f5704e0 100644
--- a/components/checker/checkercomponent.h
+++ b/components/checker/checkercomponent.h
@@ -69,6 +69,8 @@ private:
 
 	boost::mutex m_Mutex;
 	boost::condition_variable m_CV;
+	bool m_Stopped;
+	thread m_Thread;
 
 	ServiceSet m_IdleServices;
 	ServiceSet m_PendingServices;
@@ -84,7 +86,6 @@ private:
 
 	void CheckerChangedHandler(const Service::Ptr& service);
 	void NextCheckChangedHandler(const Service::Ptr& service);
-	void ObjectRemovedHandler(const DynamicObject::Ptr& object);
 
 	void RescheduleCheckTimer(void);
 };
diff --git a/components/compat/compatcomponent.cpp b/components/compat/compatcomponent.cpp
index 578cc0a05..583f11b94 100644
--- a/components/compat/compatcomponent.cpp
+++ b/components/compat/compatcomponent.cpp
@@ -257,31 +257,40 @@ void CompatComponent::DumpDowntimes(ofstream& fp, const Service::Ptr& owner, Com
 
 void CompatComponent::DumpHostStatus(ofstream& fp, const Host::Ptr& host)
 {
-	ObjectLock olock(host);
+	Service::Ptr hc;
+
+	{
+		ObjectLock olock(host);
+		hc = host->GetHostCheckService();
+
+		fp << "hoststatus {" << "\n"
+		   << "\t" << "host_name=" << host->GetName() << "\n";
+	}
+
+	ServiceState hcState = StateOK;
+
+	if (hc) {
+		ObjectLock olock(hc);
+		hcState = hc->GetState();
+	}
 
 	int state;
-	if (!host->IsReachable())
+	if (!Host::IsReachable(host))
 		state = 2; /* unreachable */
-	else if (!host->IsUp())
+	else if (hcState != StateOK)
 		state = 1; /* down */
 	else
 		state = 0; /* up */
 
-	fp << "hoststatus {" << "\n"
-	   << "\t" << "host_name=" << host->GetName() << "\n";
-
-	Service::Ptr hostcheck = host->GetHostCheckService();
-
-	if (hostcheck) {
-		DumpServiceStatusAttrs(fp, hostcheck, CompatTypeHost);
-	}
+	if (hc)
+		DumpServiceStatusAttrs(fp, hc, CompatTypeHost);
 
 	fp << "\t" << "}" << "\n"
 	   << "\n";
 
-	if (hostcheck) {
-		DumpDowntimes(fp, hostcheck, CompatTypeHost);
-		DumpComments(fp, hostcheck, CompatTypeHost);
+	if (hc) {
+		DumpDowntimes(fp, hc, CompatTypeHost);
+		DumpComments(fp, hc, CompatTypeHost);
 	}
 }
 
@@ -312,14 +321,23 @@ void CompatComponent::DumpHostObject(ofstream& fp, const Host::Ptr& host)
 
 void CompatComponent::DumpServiceStatusAttrs(ofstream& fp, const Service::Ptr& service, CompatObjectType type)
 {
-	ObjectLock olock(service);
-
 	String output;
 	String perfdata;
 	double schedule_start = -1, schedule_end = -1;
 	double execution_start = -1, execution_end = -1;
 
-	Dictionary::Ptr cr = service->GetLastCheckResult();
+	Dictionary::Ptr cr;
+	int state;
+	Host::Ptr host;
+
+	{
+		ObjectLock olock(service);
+
+		cr = service->GetLastCheckResult();
+		state = service->GetState();
+		host = service->GetHost();
+	}
+
 	if (cr) {
 		output = cr->Get("output");
 		schedule_start = cr->Get("schedule_start");
@@ -332,8 +350,6 @@ void CompatComponent::DumpServiceStatusAttrs(ofstream& fp, const Service::Ptr& s
 	double execution_time = (execution_end - execution_start);
 	double latency = (schedule_end - schedule_start) - execution_time;
 
-	int state = service->GetState();
-
 	if (state > StateUnknown)
 		state = StateUnknown;
 
@@ -343,44 +359,60 @@ void CompatComponent::DumpServiceStatusAttrs(ofstream& fp, const Service::Ptr& s
 		else
 			state = 1;
 
-		if (!service->GetHost()->IsReachable())
+		if (Host::IsReachable(host))
 			state = 2;
 	}
 
-	fp << "\t" << "check_interval=" << service->GetCheckInterval() / 60.0 << "\n"
-	   << "\t" << "retry_interval=" << service->GetRetryInterval() / 60.0 << "\n"
-	   << "\t" << "has_been_checked=" << (service->GetLastCheckResult() ? 1 : 0) << "\n"
-	   << "\t" << "should_be_scheduled=1" << "\n"
-	   << "\t" << "check_execution_time=" << execution_time << "\n"
-	   << "\t" << "check_latency=" << latency << "\n"
-	   << "\t" << "current_state=" << state << "\n"
-	   << "\t" << "state_type=" << service->GetStateType() << "\n"
-	   << "\t" << "plugin_output=" << output << "\n"
-	   << "\t" << "performance_data=" << perfdata << "\n"
-	   << "\t" << "last_check=" << schedule_end << "\n"
-	   << "\t" << "next_check=" << service->GetNextCheck() << "\n"
-	   << "\t" << "current_attempt=" << service->GetCurrentCheckAttempt() << "\n"
-	   << "\t" << "max_attempts=" << service->GetMaxCheckAttempts() << "\n"
-	   << "\t" << "last_state_change=" << service->GetLastStateChange() << "\n"
-	   << "\t" << "last_hard_state_change=" << service->GetLastHardStateChange() << "\n"
-	   << "\t" << "last_update=" << time(NULL) << "\n"
-	   << "\t" << "active_checks_enabled=" << (service->GetEnableActiveChecks() ? 1 : 0) <<"\n"
-	   << "\t" << "passive_checks_enabled=" << (service->GetEnablePassiveChecks() ? 1 : 0) << "\n"
-	   << "\t" << "problem_has_been_acknowledged=" << (service->GetAcknowledgement() != AcknowledgementNone ? 1 : 0) << "\n"
-	   << "\t" << "acknowledgement_type=" << static_cast<int>(service->GetAcknowledgement()) << "\n"
-	   << "\t" << "acknowledgement_end_time=" << service->GetAcknowledgementExpiry() << "\n"
-	   << "\t" << "scheduled_downtime_depth=" << (service->IsInDowntime() ? 1 : 0) << "\n"
-	   << "\t" << "last_notification=" << service->GetLastNotification() << "\n"
-	   << "\t" << "next_notification=" << service->GetNextNotification() << "\n";
+	{
+			ObjectLock olock(service);
+
+		fp << "\t" << "check_interval=" << service->GetCheckInterval() / 60.0 << "\n"
+		   << "\t" << "retry_interval=" << service->GetRetryInterval() / 60.0 << "\n"
+		   << "\t" << "has_been_checked=" << (service->GetLastCheckResult() ? 1 : 0) << "\n"
+		   << "\t" << "should_be_scheduled=1" << "\n"
+		   << "\t" << "check_execution_time=" << execution_time << "\n"
+		   << "\t" << "check_latency=" << latency << "\n"
+		   << "\t" << "current_state=" << state << "\n"
+		   << "\t" << "state_type=" << service->GetStateType() << "\n"
+		   << "\t" << "plugin_output=" << output << "\n"
+		   << "\t" << "performance_data=" << perfdata << "\n"
+		   << "\t" << "last_check=" << schedule_end << "\n"
+		   << "\t" << "next_check=" << service->GetNextCheck() << "\n"
+		   << "\t" << "current_attempt=" << service->GetCurrentCheckAttempt() << "\n"
+		   << "\t" << "max_attempts=" << service->GetMaxCheckAttempts() << "\n"
+		   << "\t" << "last_state_change=" << service->GetLastStateChange() << "\n"
+		   << "\t" << "last_hard_state_change=" << service->GetLastHardStateChange() << "\n"
+		   << "\t" << "last_update=" << time(NULL) << "\n"
+		   << "\t" << "active_checks_enabled=" << (service->GetEnableActiveChecks() ? 1 : 0) <<"\n"
+		   << "\t" << "passive_checks_enabled=" << (service->GetEnablePassiveChecks() ? 1 : 0) << "\n"
+		   << "\t" << "problem_has_been_acknowledged=" << (service->GetAcknowledgement() != AcknowledgementNone ? 1 : 0) << "\n"
+		   << "\t" << "acknowledgement_type=" << static_cast<int>(service->GetAcknowledgement()) << "\n"
+		   << "\t" << "acknowledgement_end_time=" << service->GetAcknowledgementExpiry() << "\n"
+		   << "\t" << "scheduled_downtime_depth=" << (service->IsInDowntime() ? 1 : 0) << "\n"
+		   << "\t" << "last_notification=" << service->GetLastNotification() << "\n"
+		   << "\t" << "next_notification=" << service->GetNextNotification() << "\n";
+	}
 }
 
 void CompatComponent::DumpServiceStatus(ofstream& fp, const Service::Ptr& service)
 {
-	ObjectLock olock(service);
+	String host_name, short_name;
+	Host::Ptr host;
+
+	{
+		ObjectLock olock(service);
+		short_name = service->GetShortName();
+		host = service->GetHost();
+	}
+
+	{
+		ObjectLock olock(host);
+		host_name = host->GetName();
+	}
 
 	fp << "servicestatus {" << "\n"
-	   << "\t" << "host_name=" << service->GetHost()->GetName() << "\n"
-	   << "\t" << "service_description=" << service->GetShortName() << "\n";
+	   << "\t" << "host_name=" << host_name << "\n"
+	   << "\t" << "service_description=" << short_name << "\n";
 
 	DumpServiceStatusAttrs(fp, service, CompatTypeService);
 
@@ -393,29 +425,47 @@ void CompatComponent::DumpServiceStatus(ofstream& fp, const Service::Ptr& servic
 
 void CompatComponent::DumpServiceObject(ofstream& fp, const Service::Ptr& service)
 {
-	ObjectLock olock(service);
-
-	fp << "define service {" << "\n"
-	   << "\t" << "host_name" << "\t" << service->GetHost()->GetName() << "\n"
-	   << "\t" << "service_description" << "\t" << service->GetShortName() << "\n"
-	   << "\t" << "display_name" << "\t" << service->GetDisplayName() << "\n"
-	   << "\t" << "check_command" << "\t" << "check_i2" << "\n"
-	   << "\t" << "check_interval" << "\t" << service->GetCheckInterval() / 60.0 << "\n"
-	   << "\t" << "retry_interval" << "\t" << service->GetRetryInterval() / 60.0 << "\n"
-	   << "\t" << "max_check_attempts" << "\t" << 1 << "\n"
-	   << "\t" << "active_checks_enabled" << "\t" << (service->GetEnableActiveChecks() ? 1 : 0) << "\n"
-	   << "\t" << "passive_checks_enabled" << "\t" << (service->GetEnablePassiveChecks() ? 1 : 0) << "\n"
-	   << "\t" << "}" << "\n"
-	   << "\n";
+	set<Service::Ptr> parentServices;
+	Host::Ptr host;
+	String host_name, short_name;
 
-	BOOST_FOREACH(const Service::Ptr& parent, service->GetParentServices()) {
+	{
+		ObjectLock olock(service);
+		parentServices = service->GetParentServices();
+		host = service->GetHost();
+		short_name = service->GetShortName();
+	}
+
+	{
+		ObjectLock olock(host);
+		host_name = host->GetName();
+	}
+
+	{
+		ObjectLock olock(service);
+
+		fp << "define service {" << "\n"
+		   << "\t" << "host_name" << "\t" << host_name << "\n"
+		   << "\t" << "service_description" << "\t" << short_name << "\n"
+		   << "\t" << "display_name" << "\t" << service->GetDisplayName() << "\n"
+		   << "\t" << "check_command" << "\t" << "check_i2" << "\n"
+		   << "\t" << "check_interval" << "\t" << service->GetCheckInterval() / 60.0 << "\n"
+		   << "\t" << "retry_interval" << "\t" << service->GetRetryInterval() / 60.0 << "\n"
+		   << "\t" << "max_check_attempts" << "\t" << 1 << "\n"
+		   << "\t" << "active_checks_enabled" << "\t" << (service->GetEnableActiveChecks() ? 1 : 0) << "\n"
+		   << "\t" << "passive_checks_enabled" << "\t" << (service->GetEnablePassiveChecks() ? 1 : 0) << "\n"
+		   << "\t" << "}" << "\n"
+		   << "\n";
+	}
+
+	BOOST_FOREACH(const Service::Ptr& parent, parentServices) {
 		ObjectLock plock(parent);
 
 		fp << "define servicedependency {" << "\n"
-		   << "\t" << "dependent_host_name" << "\t" << service->GetHost()->GetName() << "\n"
+		   << "\t" << "dependent_host_name" << "\t" << host_name << "\n"
 		   << "\t" << "dependent_service_description" << "\t" << service->GetShortName() << "\n"
 		   << "\t" << "host_name" << "\t" << parent->GetHost()->GetName() << "\n"
-		   << "\t" << "service_description" << "\t" << parent->GetShortName() << "\n"
+		   << "\t" << "service_description" << "\t" << short_name << "\n"
 		   << "\t" << "execution_failure_criteria" << "\t" << "n" << "\n"
 		   << "\t" << "notification_failure_criteria" << "\t" << "w,u,c" << "\n"
 		   << "\t" << "}" << "\n"
@@ -494,16 +544,22 @@ void CompatComponent::StatusTimerHandler(void)
 	}
 
 	BOOST_FOREACH(const DynamicObject::Ptr& object, DynamicType::GetObjects("HostGroup")) {
-		HostGroup::Ptr hg = static_pointer_cast<HostGroup>(object);
-		ObjectLock olock(hg);
+		set<Host::Ptr> members;
+
+		{
+			HostGroup::Ptr hg = static_pointer_cast<HostGroup>(object);
+			ObjectLock olock(hg);
+
+			objectfp << "define hostgroup {" << "\n"
+				 << "\t" << "hostgroup_name" << "\t" << hg->GetName() << "\n"
+				 << "\t" << "notes_url" << "\t" << hg->GetNotesUrl() << "\n"
+				 << "\t" << "action_url" << "\t" << hg->GetActionUrl() << "\n";
 
-		objectfp << "define hostgroup {" << "\n"
-			 << "\t" << "hostgroup_name" << "\t" << hg->GetName() << "\n"
-			 << "\t" << "notes_url" << "\t" << hg->GetNotesUrl() << "\n"
-			 << "\t" << "action_url" << "\t" << hg->GetActionUrl() << "\n";
+			members = hg->GetMembers();
+		}
 
 		objectfp << "\t" << "members" << "\t";
-		DumpNameList(objectfp, hg->GetMembers());
+		DumpNameList(objectfp, members);
 		objectfp << "\n"
 			 << "}" << "\n";
 	}
@@ -516,25 +572,40 @@ void CompatComponent::StatusTimerHandler(void)
 	}
 
 	BOOST_FOREACH(const DynamicObject::Ptr& object, DynamicType::GetObjects("ServiceGroup")) {
-		ServiceGroup::Ptr sg = static_pointer_cast<ServiceGroup>(object);
-		ObjectLock olock(sg);
+		set<Service::Ptr> members;
 
-		objectfp << "define servicegroup {" << "\n"
-			 << "\t" << "servicegroup_name" << "\t" << sg->GetName() << "\n"
-			 << "\t" << "notes_url" << "\t" << sg->GetNotesUrl() << "\n"
-			 << "\t" << "action_url" << "\t" << sg->GetActionUrl() << "\n";
+		{
+			ServiceGroup::Ptr sg = static_pointer_cast<ServiceGroup>(object);
+			ObjectLock olock(sg);
 
-		objectfp << "\t" << "members" << "\t";
+			objectfp << "define servicegroup {" << "\n"
+				 << "\t" << "servicegroup_name" << "\t" << sg->GetName() << "\n"
+				 << "\t" << "notes_url" << "\t" << sg->GetNotesUrl() << "\n"
+				 << "\t" << "action_url" << "\t" << sg->GetActionUrl() << "\n";
 
-		vector<String> sglist;
-		BOOST_FOREACH(const Service::Ptr& service, sg->GetMembers()) {
-			ObjectLock slock(service);
-			Host::Ptr host = service->GetHost();
+			members = sg->GetMembers();
+		}
 
-			ObjectLock hlock(host);
-			sglist.push_back(host->GetName());
+		objectfp << "\t" << "members" << "\t";
 
-			sglist.push_back(service->GetShortName());
+		vector<String> sglist;
+		BOOST_FOREACH(const Service::Ptr& service, members) {
+			Host::Ptr host;
+			String host_name, short_name;
+
+			{
+				ObjectLock olock(service);
+				host = service->GetHost();
+				short_name = service->GetShortName();
+			}
+
+			{
+				ObjectLock olock(host);
+				host_name = host->GetName();
+			}
+
+			sglist.push_back(host_name);
+			sglist.push_back(short_name);
 		}
 
 		DumpStringList(objectfp, sglist);
diff --git a/components/compatido/compatidocomponent.cpp b/components/compatido/compatidocomponent.cpp
index 3132b8994..982065ffe 100644
--- a/components/compatido/compatidocomponent.cpp
+++ b/components/compatido/compatidocomponent.cpp
@@ -438,9 +438,9 @@ void CompatIdoComponent::DumpHostStatus(const Host::Ptr& host)
 	Logger::Write(LogDebug, "compatido", log.str());
 
 	int state;
-	if (!host->IsReachable())
+	if (!Host::IsReachable(host))
 		state = 2; /* unreachable */
-	else if (!host->IsUp())
+	else if (host->GetHostCheckService()->GetState() != StateOK)
 		state = 1; /* down */
 	else
 		state = 0; /* up */
diff --git a/components/replication/replicationcomponent.cpp b/components/replication/replicationcomponent.cpp
index 3fb30b7ca..cb81abf99 100644
--- a/components/replication/replicationcomponent.cpp
+++ b/components/replication/replicationcomponent.cpp
@@ -33,6 +33,7 @@ void ReplicationComponent::Start(void)
 	DynamicObject::OnRegistered.connect(boost::bind(&ReplicationComponent::LocalObjectRegisteredHandler, this, _1));
 	DynamicObject::OnUnregistered.connect(boost::bind(&ReplicationComponent::LocalObjectUnregisteredHandler, this, _1));
 	DynamicObject::OnTransactionClosing.connect(boost::bind(&ReplicationComponent::TransactionClosingHandler, this, _2));
+	DynamicObject::OnFlushObject.connect(boost::bind(&ReplicationComponent::FlushObjectHandler, this, _1));
 
 	Endpoint::OnConnected.connect(boost::bind(&ReplicationComponent::EndpointConnectedHandler, this, _1));
 
@@ -175,11 +176,21 @@ void ReplicationComponent::TransactionClosingHandler(const set<DynamicObject::We
 		if (!object)
 			continue;
 
-		if (!ShouldReplicateObject(object))
-			continue;
+		FlushObjectHandler(object);
+	}
+}
 
-		RequestMessage request = MakeObjectMessage(object, "config::ObjectUpdate", DynamicObject::GetCurrentTx(), true);
-		EndpointManager::GetInstance()->SendMulticastMessage(m_Endpoint, request);
+void ReplicationComponent::FlushObjectHandler(const DynamicObject::Ptr& object)
+{
+	if (!ShouldReplicateObject(object))
+		return;
+
+	RequestMessage request = MakeObjectMessage(object, "config::ObjectUpdate", DynamicObject::GetCurrentTx(), true);
+
+	EndpointManager::Ptr em = EndpointManager::GetInstance();
+	{
+		ObjectLock olock(em);
+		em->SendMulticastMessage(m_Endpoint, request);
 	}
 }
 
diff --git a/components/replication/replicationcomponent.h b/components/replication/replicationcomponent.h
index 4843836f4..85aa9b40b 100644
--- a/components/replication/replicationcomponent.h
+++ b/components/replication/replicationcomponent.h
@@ -42,6 +42,7 @@ private:
 	void LocalObjectRegisteredHandler(const DynamicObject::Ptr& object);
 	void LocalObjectUnregisteredHandler(const DynamicObject::Ptr& object);
 	void TransactionClosingHandler(const set<DynamicObject::WeakPtr>& modifiedObjects);
+	void FlushObjectHandler(const DynamicObject::Ptr& object);
 
 	void RemoteObjectUpdateHandler(const RequestMessage& request);
 	void RemoteObjectRemovedHandler(const RequestMessage& request);
diff --git a/icinga-app/icinga.cpp b/icinga-app/icinga.cpp
index 01f21a5f9..124c7d68f 100644
--- a/icinga-app/icinga.cpp
+++ b/icinga-app/icinga.cpp
@@ -232,15 +232,11 @@ int main(int argc, char **argv)
 		return EXIT_FAILURE;
 	}
 
-	DynamicObject::NewTx();
-
 	bool validateOnly = g_AppParams.count("validate");
 
 	if (!LoadConfigFiles(validateOnly))
 		return EXIT_FAILURE;
 
-	DynamicObject::NewTx();
-
 	if (validateOnly) {
 		Logger::Write(LogInformation, "icinga-app", "Terminating as requested by --validate.");
 		return EXIT_SUCCESS;
diff --git a/lib/base/application.cpp b/lib/base/application.cpp
index 99218a524..952b80c69 100644
--- a/lib/base/application.cpp
+++ b/lib/base/application.cpp
@@ -149,7 +149,11 @@ void Application::RunEventLoop(void) const
 	flushTxTimer->Start();
 #endif /* _DEBUG */
 
+	Timer::Initialize();
+
 	GetEQ().Join();
+
+	Timer::Uninitialize();
 }
 
 /**
@@ -419,11 +423,8 @@ int Application::Run(void)
 	SetConsoleCtrlHandler(&Application::CtrlHandler, TRUE);
 #endif /* _WIN32 */
 
-	DynamicObject::NewTx();
-
 	result = Main();
 
-	DynamicObject::NewTx();
 	DynamicObject::DeactivateObjects();
 
 	return result;
diff --git a/lib/base/asynctask.h b/lib/base/asynctask.h
index 39c15d634..0c1e9115a 100644
--- a/lib/base/asynctask.h
+++ b/lib/base/asynctask.h
@@ -86,7 +86,6 @@ public:
 	 */
 	TResult GetResult(void)
 	{
-		boost::mutex::scoped_lock lock(m_Mutex);
 		if (!m_Finished)
 			BOOST_THROW_EXCEPTION(runtime_error("GetResult called on an unfinished AsyncTask"));
 
@@ -110,7 +109,6 @@ public:
 	 */
 	void FinishException(const boost::exception_ptr& ex)
 	{
-		boost::mutex::scoped_lock lock(m_Mutex);
 		m_Exception = ex;
 		FinishInternal();
 	}
@@ -122,7 +120,6 @@ public:
 	 */
 	void FinishResult(const TResult& result)
 	{
-		boost::mutex::scoped_lock lock(m_Mutex);
 		m_Result = result;
 		FinishInternal();
 	}
@@ -149,24 +146,24 @@ private:
 	/**
 	 * Finishes the task and causes the completion callback to be invoked. This
 	 * function must be called before the object is destroyed.
-	 *
-	 * @threadsafety Caller must hold m_Mutex.
 	 */
 	void FinishInternal(void)
 	{
-		assert(!m_Finished);
+		CompletionCallback callback;
 
-		m_Finished = true;
+		{
+			boost::mutex::scoped_lock lock(m_Mutex);
+			assert(!m_Finished);
 
-		m_CV.notify_all();
+			m_Finished = true;
 
-		if (!m_CompletionCallback.empty()) {
-			Utility::QueueAsyncCallback(boost::bind(m_CompletionCallback, GetSelf()));
+			m_CV.notify_all();
 
-			/* Clear callback because the bound function might hold a
-			 * reference to this task. */
-			m_CompletionCallback = CompletionCallback();
+			m_CompletionCallback.swap(callback);
 		}
+
+		if (!callback.empty())
+			Utility::QueueAsyncCallback(boost::bind(callback, GetSelf()));
 	}
 
 	mutable boost::mutex m_Mutex;
diff --git a/lib/base/dynamicobject.cpp b/lib/base/dynamicobject.cpp
index 51e8f07c6..81dc93bee 100644
--- a/lib/base/dynamicobject.cpp
+++ b/lib/base/dynamicobject.cpp
@@ -30,6 +30,7 @@ Timer::Ptr DynamicObject::m_TransactionTimer;
 signals2::signal<void (const DynamicObject::Ptr&)> DynamicObject::OnRegistered;
 signals2::signal<void (const DynamicObject::Ptr&)> DynamicObject::OnUnregistered;
 signals2::signal<void (double, const set<DynamicObject::WeakPtr>&)> DynamicObject::OnTransactionClosing;
+signals2::signal<void (const DynamicObject::Ptr&)> DynamicObject::OnFlushObject;
 
 DynamicObject::DynamicObject(const Dictionary::Ptr& serializedObject)
 	: m_Events(false), m_ConfigTx(0)
@@ -527,11 +528,20 @@ double DynamicObject::GetCurrentTx(void)
 {
 	boost::mutex::scoped_lock lock(m_TransactionMutex);
 
-	assert(m_CurrentTx != 0);
+	if (m_CurrentTx == 0) {
+		/* Set the initial transaction ID. */
+		m_CurrentTx = Utility::GetTime();
+	}
 
 	return m_CurrentTx;
 }
 
+void DynamicObject::Flush(void)
+{
+	SendLocalUpdateEvents();
+	OnFlushObject(GetSelf());
+}
+
 /*
  * @threadsafety Always. Caller must not hold any Object locks.
  */
diff --git a/lib/base/dynamicobject.h b/lib/base/dynamicobject.h
index e78d7cfad..ea18ff98e 100644
--- a/lib/base/dynamicobject.h
+++ b/lib/base/dynamicobject.h
@@ -99,6 +99,7 @@ public:
 	static signals2::signal<void (const DynamicObject::Ptr&)> OnRegistered;
 	static signals2::signal<void (const DynamicObject::Ptr&)> OnUnregistered;
 	static signals2::signal<void (double, const set<DynamicObject::WeakPtr>&)> OnTransactionClosing;
+	static signals2::signal<void (const DynamicObject::Ptr&)> OnFlushObject;
 
 	ScriptTask::Ptr MakeMethodTask(const String& method,
 	    const vector<Value>& arguments);
@@ -115,6 +116,8 @@ public:
 	void SetTx(double tx);
 	double GetTx(void) const;
 
+	void Flush(void);
+
 	void Register(void);
 	void Unregister(void);
 
@@ -132,7 +135,6 @@ public:
 	static void DeactivateObjects(void);
 
 	static double GetCurrentTx(void);
-	static void NewTx(void);
 
 protected:
 	virtual void OnInitCompleted(void);
@@ -151,6 +153,8 @@ private:
 
 	static double m_CurrentTx;
 
+	static void NewTx(void);
+
 	/* This has to be a set of raw pointers because the DynamicObject
 	 * constructor has to be able to insert objects into this list. */
 	static set<DynamicObject::WeakPtr> m_ModifiedObjects;
diff --git a/lib/base/dynamictype.cpp b/lib/base/dynamictype.cpp
index 144e9069f..df76b4a87 100644
--- a/lib/base/dynamictype.cpp
+++ b/lib/base/dynamictype.cpp
@@ -83,11 +83,20 @@ void DynamicType::RegisterObject(const DynamicObject::Ptr& object)
 	ObjectLock olock(object);
 	object->SetEvents(true);
 
-	if (m_ObjectMap.find(object->GetName()) != m_ObjectMap.end())
+	ObjectMap::iterator it = m_ObjectMap.find(object->GetName());
+
+	if (it != m_ObjectMap.end()) {
+		if (it->second == object)
+			return;
+
 		BOOST_THROW_EXCEPTION(runtime_error("RegisterObject() found existing object with the same name: " + object->GetName()));
+	}
 
 	m_ObjectMap[object->GetName()] = object;
 	m_ObjectSet.insert(object);
+
+	/* notify the object that it's been fully initialized */
+	object->OnInitCompleted();
 }
 
 void DynamicType::UnregisterObject(const DynamicObject::Ptr& object)
@@ -128,22 +137,19 @@ void DynamicType::RegisterType(const DynamicType::Ptr& type)
 
 DynamicObject::Ptr DynamicType::CreateObject(const Dictionary::Ptr& serializedUpdate) const
 {
-	DynamicObject::Ptr obj = m_ObjectFactory(serializedUpdate);
-	ObjectLock olock(obj);
+	DynamicObject::Ptr object = m_ObjectFactory(serializedUpdate);
+	ObjectLock olock(object);
 
 	/* register attributes */
 	String name;
 	DynamicAttributeType type;
 	BOOST_FOREACH(tuples::tie(name, type), m_Attributes)
-		obj->RegisterAttribute(name, type);
+		object->RegisterAttribute(name, type);
 
 	/* apply the object's non-config attributes */
-	obj->ApplyUpdate(serializedUpdate, Attribute_All & ~Attribute_Config);
-
-	/* notify the object that it's been fully initialized */
-	obj->OnInitCompleted();
+	object->ApplyUpdate(serializedUpdate, Attribute_All & ~Attribute_Config);
 
-	return obj;
+	return object;
 }
 
 /**
diff --git a/lib/base/eventqueue.cpp b/lib/base/eventqueue.cpp
index 7fe42a886..6eb47bab5 100644
--- a/lib/base/eventqueue.cpp
+++ b/lib/base/eventqueue.cpp
@@ -32,7 +32,7 @@ EventQueue::EventQueue(void)
 	if (thread_count < 4)
 		thread_count = 4;
 
-	thread_count *= 8;
+	thread_count *= 4;
 
 	for (int i = 0; i < thread_count; i++)
 		m_Threads.create_thread(boost::bind(&EventQueue::QueueThreadProc, this));
@@ -74,7 +74,7 @@ void EventQueue::Join(void)
  */
 void EventQueue::QueueThreadProc(void)
 {
-	while (!m_Stopped) {
+	for (;;) {
 		vector<Callback> events;
 
 		{
@@ -83,6 +83,9 @@ void EventQueue::QueueThreadProc(void)
 			while (m_Events.empty() && !m_Stopped)
 				m_CV.wait(lock);
 
+			if (m_Stopped)
+				break;
+
 			events.swap(m_Events);
 		}
 
@@ -112,5 +115,5 @@ void EventQueue::Post(const EventQueue::Callback& callback)
 {
 	boost::mutex::scoped_lock lock(m_Mutex);
 	m_Events.push_back(callback);
-	m_CV.notify_all();
+	m_CV.notify_one();
 }
diff --git a/lib/base/object.cpp b/lib/base/object.cpp
index 51e055609..c409d87a0 100644
--- a/lib/base/object.cpp
+++ b/lib/base/object.cpp
@@ -41,7 +41,6 @@ Object::~Object(void)
  */
 Object::SharedPtrHolder Object::GetSelf(void)
 {
-	ObjectLock olock(this);
 	return Object::SharedPtrHolder(shared_from_this());
 }
 
diff --git a/lib/base/process-unix.cpp b/lib/base/process-unix.cpp
index 2331e37c9..9e852a765 100644
--- a/lib/base/process-unix.cpp
+++ b/lib/base/process-unix.cpp
@@ -133,7 +133,8 @@ void Process::WorkerThreadProc(int taskFd)
 					if (fd >= 0)
 						tasks[fd] = task;
 				} catch (...) {
-					Application::GetEQ().Post(boost::bind(&Process::FinishException, task, boost::current_exception()));
+					ObjectLock olock(task);
+					task->FinishException(boost::current_exception());
 				}
 			}
 
@@ -148,7 +149,8 @@ void Process::WorkerThreadProc(int taskFd)
 				prev = it;
 				tasks.erase(prev);
 
-				Application::GetEQ().Post(boost::bind(&Process::FinishResult, task, task->m_Result));
+				ObjectLock olock(task);
+				task->FinishResult(task->m_Result);
 			}
 		}
 	}
diff --git a/lib/base/process.cpp b/lib/base/process.cpp
index d959c0102..58e8b2736 100644
--- a/lib/base/process.cpp
+++ b/lib/base/process.cpp
@@ -28,7 +28,10 @@ deque<Process::Ptr> Process::m_Tasks;
 Process::Process(const vector<String>& arguments, const Dictionary::Ptr& extraEnvironment)
 	: AsyncTask<Process, ProcessResult>(), m_Arguments(arguments), m_ExtraEnvironment(extraEnvironment)
 {
-	boost::call_once(&Process::Initialize, m_ThreadOnce);
+	{
+		boost::mutex::scoped_lock lock(m_Mutex);
+		boost::call_once(&Process::Initialize, m_ThreadOnce);
+	}
 
 #ifndef _WIN32
 	m_FD = -1;
diff --git a/lib/base/streamlogger.cpp b/lib/base/streamlogger.cpp
index 1196ee1ed..80ee402df 100644
--- a/lib/base/streamlogger.cpp
+++ b/lib/base/streamlogger.cpp
@@ -83,6 +83,8 @@ void StreamLogger::ProcessLogEntry(ostream& stream, bool tty, const LogEntry& en
 
 	strftime(timestamp, sizeof(timestamp), "%Y/%m/%d %H:%M:%S %z", &tmnow);
 
+	boost::mutex::scoped_lock lock(m_Mutex);
+
 	if (tty) {
 		switch (entry.Severity) {
 			case LogWarning:
@@ -96,7 +98,6 @@ void StreamLogger::ProcessLogEntry(ostream& stream, bool tty, const LogEntry& en
 		}
 	}
 
-	boost::mutex::scoped_lock lock(m_Mutex);
 	stream << "[" << timestamp << "] "
 		 << Logger::SeverityToString(entry.Severity) << "/" << entry.Facility << ": "
 		 << entry.Message;
diff --git a/lib/base/timer.cpp b/lib/base/timer.cpp
index b3cd64384..9d3098560 100644
--- a/lib/base/timer.cpp
+++ b/lib/base/timer.cpp
@@ -22,9 +22,10 @@
 using namespace icinga;
 
 Timer::TimerSet Timer::m_Timers;
+thread Timer::m_Thread;
 boost::mutex Timer::m_Mutex;
 boost::condition_variable Timer::m_CV;
-boost::once_flag Timer::m_ThreadOnce = BOOST_ONCE_INIT;
+bool Timer::m_StopThread;
 
 /**
  * Extracts the next timestamp from a Timer.
@@ -59,8 +60,25 @@ Timer::Timer(void)
  */
 void Timer::Initialize(void)
 {
-	thread worker(boost::bind(&Timer::TimerThreadProc));
-	worker.detach();
+	boost::mutex::scoped_lock lock(m_Mutex);
+	m_StopThread = false;
+	m_Thread = thread(boost::bind(&Timer::TimerThreadProc));
+}
+
+/**
+ * Disables the timer sub-system.
+ *
+ * @threadsafety Always.
+ */
+void Timer::Uninitialize(void)
+{
+	{
+		boost::mutex::scoped_lock lock(m_Mutex);
+		m_StopThread = true;
+		m_CV.notify_all();
+	}
+
+	m_Thread.join();
 }
 
 /**
@@ -70,18 +88,8 @@ void Timer::Initialize(void)
  */
 void Timer::Call(void)
 {
-	double st = Utility::GetTime();
-
 	OnTimerExpired(GetSelf());
 
-	double et = Utility::GetTime();
-
-	if (et - st > 1.0) {
-		stringstream msgbuf;
-		msgbuf << "Timer call took " << et - st << " seconds.";
-		Logger::Write(LogWarning, "base", msgbuf.str());
-	}
-
 	/* Re-enable the timer so it can be called again. */
 	m_Started = true;
 	Reschedule();
@@ -118,8 +126,6 @@ double Timer::GetInterval(void) const
  */
 void Timer::Start(void)
 {
-	boost::call_once(&Timer::Initialize, m_ThreadOnce);
-
 	m_Started = true;
 
 	Reschedule();
@@ -232,9 +238,12 @@ void Timer::TimerThreadProc(void)
 		NextTimerView& idx = boost::get<1>(m_Timers);
 
 		/* Wait until there is at least one timer. */
-		while (idx.empty())
+		while (idx.empty() && !m_StopThread)
 			m_CV.wait(lock);
 
+		if (m_StopThread)
+			break;
+
 		NextTimerView::iterator it = idx.begin();
 		Timer::Ptr timer = it->lock();
 
diff --git a/lib/base/timer.h b/lib/base/timer.h
index a2126b9fa..e06ad26a1 100644
--- a/lib/base/timer.h
+++ b/lib/base/timer.h
@@ -64,6 +64,9 @@ public:
 
 	signals2::signal<void(const Timer::Ptr&)> OnTimerExpired;
 
+	static void Initialize(void);
+	static void Uninitialize(void);
+
 private:
 	double m_Interval; /**< The interval of the timer. */
 	double m_Next; /**< When the next event should happen. */
@@ -79,13 +82,12 @@ private:
 
 	static boost::mutex m_Mutex;
 	static boost::condition_variable m_CV;
+	static thread m_Thread;
+	static bool m_StopThread;
 	static TimerSet m_Timers;
 
 	void Call(void);
 
-	static boost::once_flag m_ThreadOnce;
-	static void Initialize(void);
-
 	static void TimerThreadProc(void);
 
 	friend struct TimerNextExtractor;
diff --git a/lib/config/configitem.cpp b/lib/config/configitem.cpp
index 784f63ec7..8a50fd9be 100644
--- a/lib/config/configitem.cpp
+++ b/lib/config/configitem.cpp
@@ -383,18 +383,14 @@ void ConfigItem::UnloadUnit(const String& unit)
 
 	vector<ConfigItem::Ptr> obsoleteItems;
 
-	{
-		boost::mutex::scoped_lock lock(m_Mutex);
-
-		ConfigItem::Ptr item;
-		BOOST_FOREACH(tie(tuples::ignore, item), m_Items) {
-			ObjectLock olock(item);
+	ConfigItem::Ptr item;
+	BOOST_FOREACH(tie(tuples::ignore, item), m_Items) {
+		ObjectLock olock(item);
 
-			if (item->GetUnit() != unit)
-				continue;
+		if (item->GetUnit() != unit)
+			continue;
 
-			obsoleteItems.push_back(item);
-		}
+		obsoleteItems.push_back(item);
 	}
 
 	BOOST_FOREACH(const ConfigItem::Ptr& item, obsoleteItems) {
diff --git a/lib/icinga/externalcommandprocessor.cpp b/lib/icinga/externalcommandprocessor.cpp
index 337d36ea6..fd22a52f4 100644
--- a/lib/icinga/externalcommandprocessor.cpp
+++ b/lib/icinga/externalcommandprocessor.cpp
@@ -349,12 +349,12 @@ void ExternalCommandProcessor::AcknowledgeHostProblem(double, const vector<Strin
 
 	Host::Ptr host = Host::GetByName(arguments[0]);
 
-	if (host->IsUp())
-		BOOST_THROW_EXCEPTION(invalid_argument("The host '" + arguments[0] + "' is OK."));
-
 	Logger::Write(LogInformation, "icinga", "Setting acknowledgement for host '" + host->GetName() + "'");
 	Service::Ptr service = host->GetHostCheckService();
 	if (service) {
+		if (service->GetState() == StateOK)
+			BOOST_THROW_EXCEPTION(invalid_argument("The host '" + arguments[0] + "' is OK."));
+
 		service->SetAcknowledgement(sticky ? AcknowledgementSticky : AcknowledgementNormal);
 		service->SetAcknowledgementExpiry(0);
 	}
@@ -370,12 +370,12 @@ void ExternalCommandProcessor::AcknowledgeHostProblemExpire(double, const vector
 
 	Host::Ptr host = Host::GetByName(arguments[0]);
 
-	if (host->IsUp())
-		BOOST_THROW_EXCEPTION(invalid_argument("The host '" + arguments[0] + "' is OK."));
-
 	Logger::Write(LogInformation, "icinga", "Setting timed acknowledgement for host '" + host->GetName() + "'");
 	Service::Ptr service = host->GetHostCheckService();
 	if (service) {
+		if (service->GetState() == StateOK)
+			BOOST_THROW_EXCEPTION(invalid_argument("The host '" + arguments[0] + "' is OK."));
+
 		service->SetAcknowledgement(sticky ? AcknowledgementSticky : AcknowledgementNormal);
 		service->SetAcknowledgementExpiry(timestamp);
 	}
diff --git a/lib/icinga/host.cpp b/lib/icinga/host.cpp
index bd22f4297..5c5e0bf0d 100644
--- a/lib/icinga/host.cpp
+++ b/lib/icinga/host.cpp
@@ -34,7 +34,14 @@ REGISTER_TYPE(Host, hostAttributes);
 
 Host::Host(const Dictionary::Ptr& properties)
 	: DynamicObject(properties)
-{ }
+{
+	HostGroup::InvalidateMembersCache();
+}
+
+void Host::OnInitCompleted(void)
+{
+	UpdateSlaveServices();
+}
 
 Host::~Host(void)
 {
@@ -105,9 +112,18 @@ String Host::GetHostCheck(void) const
 	return Get("hostcheck");
 }
 
-bool Host::IsReachable(void)
+bool Host::IsReachable(const Host::Ptr& self)
 {
-	BOOST_FOREACH(const Service::Ptr& service, GetParentServices()) {
+	set<Service::Ptr> parentServices;
+
+	{
+		ObjectLock olock(self);
+		parentServices = self->GetParentServices();
+	}
+
+	BOOST_FOREACH(const Service::Ptr& service, parentServices) {
+		ObjectLock olock(service);
+
 		/* ignore pending services */
 		if (!service->GetLastCheckResult())
 			continue;
@@ -124,37 +140,29 @@ bool Host::IsReachable(void)
 		return false;
 	}
 
-	BOOST_FOREACH(const Host::Ptr& host, GetParentHosts()) {
-		/* ignore hosts that are up */
-		if (host->IsUp())
-			continue;
+	set<Host::Ptr> parentHosts;
 
-		return false;
+	{
+		ObjectLock olock(self);
+		parentHosts = self->GetParentHosts();
 	}
 
-	return true;
-}
-
-bool Host::IsInDowntime(void) const
-{
-	Service::Ptr service = GetHostCheckService();
-
-	if (!service)
-		return false;
+	BOOST_FOREACH(const Host::Ptr& host, parentHosts) {
+		Service::Ptr hc;
 
-	ObjectLock olock(service);
-	return (service || service->IsInDowntime());
-}
+		{
+			ObjectLock olock(host);
+			hc = host->GetHostCheckService();
+		}
 
-bool Host::IsUp(void) const
-{
-	Service::Ptr service = GetHostCheckService();
+		/* ignore hosts that are up */
+		if (hc && hc->GetState() == StateOK)
+			continue;
 
-	if (!service)
-		return true;
+		return false;
+	}
 
-	ObjectLock olock(service);
-	return (service->GetState() == StateOK || service->GetState() == StateWarning);
+	return true;
 }
 
 template<bool copyServiceAttrs, typename TDict>
@@ -280,10 +288,19 @@ void Host::OnAttributeChanged(const String& name, const Value&)
 {
 	if (name == "hostgroups")
 		HostGroup::InvalidateMembersCache();
-	else if (name == "services")
+	else if (name == "services") {
+		ObjectLock olock(this);
 		UpdateSlaveServices();
-	else if (name == "notifications") {
-		BOOST_FOREACH(const Service::Ptr& service, GetServices()) {
+	} else if (name == "notifications") {
+		set<Service::Ptr> services;
+
+		{
+			ObjectLock olock(this);
+			services = GetServices();
+		}
+
+		BOOST_FOREACH(const Service::Ptr& service, services) {
+			ObjectLock olock(service);
 			service->UpdateSlaveNotifications();
 		}
 	}
diff --git a/lib/icinga/host.h b/lib/icinga/host.h
index 7b4d18139..936da7dac 100644
--- a/lib/icinga/host.h
+++ b/lib/icinga/host.h
@@ -56,9 +56,7 @@ public:
 	set<Host::Ptr> GetParentHosts(void) const;
 	set<shared_ptr<Service> > GetParentServices(void) const;
 
-	bool IsReachable(void);
-	bool IsInDowntime(void) const;
-	bool IsUp(void) const;
+	static bool IsReachable(const Host::Ptr& self);
 
 	shared_ptr<Service> GetServiceByShortName(const Value& name) const;
 
@@ -69,6 +67,7 @@ public:
 	    const std::vector<icinga::Value>& arguments);
 
 protected:
+	void OnInitCompleted(void);
 	void OnAttributeChanged(const String& name, const Value& oldValue);
 
 private:
diff --git a/lib/icinga/notification.cpp b/lib/icinga/notification.cpp
index 1c080b604..5d90a6d35 100644
--- a/lib/icinga/notification.cpp
+++ b/lib/icinga/notification.cpp
@@ -95,7 +95,10 @@ void Notification::NotificationCompletedHandler(const ScriptTask::Ptr& task)
 	m_Tasks.erase(task);
 
 	try {
-		(void) task->GetResult();
+		{
+			ObjectLock tlock(task);
+			(void) task->GetResult();
+		}
 
 		Logger::Write(LogInformation, "icinga", "Completed sending notification for service '" + GetService()->GetName() + "'");
 	} catch (const exception& ex) {
diff --git a/lib/icinga/pluginnotificationtask.cpp b/lib/icinga/pluginnotificationtask.cpp
index 4832ec500..c66671180 100644
--- a/lib/icinga/pluginnotificationtask.cpp
+++ b/lib/icinga/pluginnotificationtask.cpp
@@ -97,7 +97,10 @@ void PluginNotificationTask::ProcessFinishedHandler(PluginNotificationTask ct)
 	ProcessResult pr;
 
 	try {
-		pr = ct.m_Process->GetResult();
+		{
+			ObjectLock tlock(ct.m_Process);
+			pr = ct.m_Process->GetResult();
+		}
 
 		if (pr.ExitStatus != 0) {
 			stringstream msgbuf;
diff --git a/lib/icinga/service-check.cpp b/lib/icinga/service-check.cpp
index 0fcab976c..579d6b92b 100644
--- a/lib/icinga/service-check.cpp
+++ b/lib/icinga/service-check.cpp
@@ -350,9 +350,9 @@ void Service::ApplyCheckResult(const Dictionary::Ptr& cr)
 
 		/* Make sure the notification component sees the updated
 		 * state/state_type attributes. */
-		DynamicObject::NewTx();
+		Flush();
 
-		if (IsReachable() && !IsInDowntime() && !IsAcknowledged())
+		if (IsReachable(GetSelf()) && !IsInDowntime() && !IsAcknowledged())
 			RequestNotifications(NotificationStateChange);
 	}
 }
@@ -457,7 +457,12 @@ void Service::CheckCompletedHandler(const Dictionary::Ptr& scheduleInfo,
 	Dictionary::Ptr result;
 
 	try {
-		Value vresult = task->GetResult();
+		Value vresult;
+
+		{
+			ObjectLock tlock(task);
+			vresult = task->GetResult();
+		}
 
 		if (vresult.IsObjectType<Dictionary>())
 			result = vresult;
@@ -510,9 +515,9 @@ void Service::ProcessCheckResult(const Dictionary::Ptr& cr)
 
 	Service::UpdateStatistics(cr);
 
-	/* flush the current transaction so other instances see the service's
+	/* Flush the object so other instances see the service's
 	 * new state when they receive the CheckResult message */
-	DynamicObject::NewTx();
+	Flush();
 
 	RequestMessage rm;
 	rm.SetMethod("checker::CheckResult");
diff --git a/lib/icinga/service-notification.cpp b/lib/icinga/service-notification.cpp
index 7e684e4ff..21ba7a737 100644
--- a/lib/icinga/service-notification.cpp
+++ b/lib/icinga/service-notification.cpp
@@ -125,7 +125,17 @@ void Service::UpdateSlaveNotifications(void)
 	newNotifications = boost::make_shared<Dictionary>();
 
 	vector<Dictionary::Ptr> notificationDescsList;
-	notificationDescsList.push_back(GetHost()->Get("notifications"));
+
+	String host_name;
+
+	{
+		Host::Ptr host = GetHost();
+		ObjectLock olock(host);
+
+		notificationDescsList.push_back(host->Get("notifications"));
+		host_name = host->GetName();
+	}
+
 	notificationDescsList.push_back(Get("notifications"));
 
 	BOOST_FOREACH(const Dictionary::Ptr& notificationDescs, notificationDescsList) {
@@ -145,7 +155,7 @@ void Service::UpdateSlaveNotifications(void)
 			ConfigItemBuilder::Ptr builder = boost::make_shared<ConfigItemBuilder>(item->GetDebugInfo());
 			builder->SetType("Notification");
 			builder->SetName(name);
-			builder->AddExpression("host_name", OperatorSet, GetHost()->GetName());
+			builder->AddExpression("host_name", OperatorSet, host_name);
 			builder->AddExpression("service", OperatorSet, GetName());
 
 			CopyNotificationAttributes(this, builder);
diff --git a/lib/icinga/service.cpp b/lib/icinga/service.cpp
index 5eb15257d..e2f1f68a7 100644
--- a/lib/icinga/service.cpp
+++ b/lib/icinga/service.cpp
@@ -47,7 +47,17 @@ REGISTER_TYPE(Service, serviceAttributes);
 
 Service::Service(const Dictionary::Ptr& serializedObject)
 	: DynamicObject(serializedObject)
-{ }
+{
+	ServiceGroup::InvalidateMembersCache();
+	Host::InvalidateServicesCache();
+	Service::InvalidateDowntimesCache();
+	Service::InvalidateCommentsCache();
+}
+
+void Service::OnInitCompleted(void)
+{
+	UpdateSlaveNotifications();
+}
 
 Service::~Service(void)
 {
@@ -142,9 +152,18 @@ String Service::GetShortName(void) const
 	return value;
 }
 
-bool Service::IsReachable(void) const
+bool Service::IsReachable(const Service::Ptr& self)
 {
-	BOOST_FOREACH(const Service::Ptr& service, GetParentServices()) {
+	set<Service::Ptr> parentServices;
+
+	{
+		ObjectLock olock(self);
+		parentServices = self->GetParentServices();
+	}
+
+	BOOST_FOREACH(const Service::Ptr& service, parentServices) {
+		ObjectLock olock(service);
+
 		/* ignore pending services */
 		if (!service->GetLastCheckResult())
 			continue;
@@ -161,9 +180,23 @@ bool Service::IsReachable(void) const
 		return false;
 	}
 
-	BOOST_FOREACH(const Host::Ptr& host, GetParentHosts()) {
+	set<Host::Ptr> parentHosts;
+
+	{
+		ObjectLock olock(self);
+		parentHosts = self->GetParentHosts();
+	}
+
+	BOOST_FOREACH(const Host::Ptr& host, parentHosts) {
+		Service::Ptr hc;
+
+		{
+			ObjectLock olock(host);
+			hc = host->GetHostCheckService();
+		}
+
 		/* ignore hosts that are up */
-		if (host->IsUp())
+		if (hc && hc->GetState() == StateOK)
 			continue;
 
 		return false;
@@ -222,8 +255,6 @@ void Service::SetAcknowledgementExpiry(double timestamp)
 
 void Service::OnAttributeChanged(const String& name, const Value& oldValue)
 {
-	ObjectLock olock(this);
-
 	if (name == "checker")
 		OnCheckerChanged(GetSelf(), oldValue);
 	else if (name == "next_check")
@@ -232,7 +263,11 @@ void Service::OnAttributeChanged(const String& name, const Value& oldValue)
 		ServiceGroup::InvalidateMembersCache();
 	else if (name == "host_name" || name == "short_name") {
 		Host::InvalidateServicesCache();
-		UpdateSlaveNotifications();
+
+		{
+			ObjectLock olock(this);
+			UpdateSlaveNotifications();
+		}
 	} else if (name == "downtimes")
 		Service::InvalidateDowntimesCache();
 	else if (name == "comments")
@@ -240,6 +275,7 @@ void Service::OnAttributeChanged(const String& name, const Value& oldValue)
 	else if (name == "notifications")
 		UpdateSlaveNotifications();
 	else if (name == "check_interval") {
+		ObjectLock(this);
 		ConfigItem::Ptr item = ConfigItem::GetObject("Service", GetName());
 
 		/* update the next check timestamp if we're the owner of this service */
diff --git a/lib/icinga/service.h b/lib/icinga/service.h
index 2c3d9e99d..8a44fc198 100644
--- a/lib/icinga/service.h
+++ b/lib/icinga/service.h
@@ -111,7 +111,7 @@ public:
 	set<Host::Ptr> GetParentHosts(void) const;
 	set<Service::Ptr> GetParentServices(void) const;
 
-	bool IsReachable(void) const;
+	bool IsReachable(const Service::Ptr& self);
 
 	AcknowledgementType GetAcknowledgement(void);
 	void SetAcknowledgement(AcknowledgementType acknowledgement);
@@ -248,6 +248,7 @@ public:
 	void SetNextNotification(double time);
 
 protected:
+	virtual void OnInitCompleted(void);
 	virtual void OnAttributeChanged(const String& name, const Value& oldValue);
 
 private: