Detach idle worker attachments after 60 seconds of inactivity to free system resources and metadata locks.

Also, publish worker attachments for monitoring.

src/common/classes/TimerImpl.cpp

@@ -27,7 +27,6 @@
 
 #include "../../common/classes/TimerImpl.h"
 #include "../../common/StatusHolder.h"
-#include "../../common/ThreadStart.h"
 #include "../../common/utils_proto.h"
 
 namespace Firebird {
@@ -36,7 +35,7 @@ void TimerImpl::handler()
 {
 	{
 		MutexLockGuard guard(m_mutex, FB_FUNCTION);
-		fb_assert(!m_inHandler);
+		fb_assert(!m_handlerTid);
 
 		m_fireTime = 0;
 		if (!m_expTime)	// Timer was reset to zero or stopped, do nothing
@@ -54,7 +53,7 @@ void TimerImpl::handler()
 		m_expTime = 0;
 
 		if (m_onTimer)
-			m_inHandler = true;
+			m_handlerTid = Thread::getId();
 	}
 
 	if (!m_onTimer)
@@ -63,7 +62,7 @@ void TimerImpl::handler()
 	m_onTimer(this);
 
 	MutexLockGuard guard(m_mutex, FB_FUNCTION);
-	m_inHandler = false;
+	m_handlerTid = 0;
 }
 
 void TimerImpl::reset(unsigned int timeout)
@@ -108,8 +107,12 @@ void TimerImpl::stop()
 {
 	MutexLockGuard guard(m_mutex, FB_FUNCTION);
 
+	// Allow handler() to call stop()
+	if (m_handlerTid == Thread::getId())
+		return;
+
 	// hvlad: it could be replaced by condition variable when we have good one for Windows
-	while (m_inHandler)
+	while (m_handlerTid)
 	{
 		MutexUnlockGuard unlock(m_mutex, FB_FUNCTION);
 		Thread::sleep(10);

src/common/classes/TimerImpl.h

@@ -32,6 +32,7 @@
 
 #include "../../common/classes/ImplementHelper.h"
 #include "../../common/classes/locks.h"
+#include "../../common/ThreadStart.h"
 
 namespace Firebird {
 
@@ -51,7 +52,7 @@ public:
 	TimerImpl() :
 		m_fireTime(0),
 		m_expTime(0),
-		m_inHandler(false)
+		m_handlerTid(0)
 	{ }
 
 	// ITimer implementation
@@ -82,9 +83,9 @@ public:
 private:
 	Mutex m_mutex;
 	SINT64 m_fireTime;		// when ITimer will fire, could be less than m_expTime
-	SINT64 m_expTime;		// when actual idle timeout will expire
+	SINT64 m_expTime;		// when actual timeout will expire
 	std::function<OnTimerFunc> m_onTimer;
-	bool m_inHandler;
+	ThreadId m_handlerTid;	// ID of handler thread, if handler is running
 };
 
 

src/jrd/Attachment.cpp

@@ -1036,7 +1036,7 @@ void StableAttachmentPart::manualAsyncUnlock(ULONG& flags)
 	}
 }
 
-void StableAttachmentPart::onIdleTimer(TimerImpl*)
+void StableAttachmentPart::doOnIdleTimer(TimerImpl*)
 {
 	// Ensure attachment is still alive and still idle
 
@@ -1075,8 +1075,11 @@ void Attachment::setupIdleTimer(bool clear)
 	{
 		if (!att_idle_timer)
 		{
-			att_idle_timer = FB_NEW IdleTimer(getStable());
+			using IdleTimer = TimerWithRef<StableAttachmentPart>;
-			att_idle_timer->setOnTimer(&StableAttachmentPart::onIdleTimer);
+
+			auto idleTimer = FB_NEW IdleTimer(getStable());
+			idleTimer->setOnTimer(&StableAttachmentPart::onIdleTimer);
+			att_idle_timer = idleTimer;
 		}
 
 		att_idle_timer->reset(timeout);

src/jrd/Attachment.h

@@ -374,7 +374,13 @@ public:
 		return shutError;
 	}
 
-	void onIdleTimer(Firebird::TimerImpl*);
+	void onIdleTimer(Firebird::TimerImpl* timer)
+	{
+		doOnIdleTimer(timer);
+	}
+
+protected:
+	virtual void doOnIdleTimer(Firebird::TimerImpl* timer);
 
 private:
 	Attachment* att;
@@ -809,9 +815,7 @@ private:
 
 	unsigned int att_idle_timeout;		// seconds
 	unsigned int att_stmt_timeout;		// milliseconds
-
+	Firebird::RefPtr<Firebird::TimerImpl> att_idle_timer;
-	typedef Firebird::TimerWithRef<StableAttachmentPart> IdleTimer;
-	Firebird::RefPtr<IdleTimer> att_idle_timer;
 
 	Firebird::Array<JBatch*> att_batches;
 	InitialOptions att_initial_options;	// Initial session options

src/jrd/WorkerAttachment.cpp

@@ -45,6 +45,8 @@ using namespace Firebird;
 namespace Jrd {
 
 
+const unsigned WORKER_IDLE_TIMEOUT = 60;	// 1 minute
+
 /// class WorkerStableAttachment
 
 WorkerStableAttachment::WorkerStableAttachment(FbStatusVector* status, Jrd::Attachment* attachment) :
@@ -65,6 +67,7 @@ WorkerStableAttachment::WorkerStableAttachment(FbStatusVector* status, Jrd::Atta
 	PAG_header(tdbb, true);
 	PAG_attachment_id(tdbb);
 	TRA_init(attachment);
+	Monitoring::publishAttachment(tdbb);
 
 	initDone();
 }
@@ -97,6 +100,11 @@ WorkerStableAttachment* WorkerStableAttachment::create(FbStatusVector* status, J
 	return NULL;
 }
 
+void WorkerStableAttachment::doOnIdleTimer(Firebird::TimerImpl* timer)
+{
+	WorkerAttachment::detachIdle(this);
+}
+
 void WorkerStableAttachment::fini()
 {
 	Attachment* attachment = NULL;
@@ -232,7 +240,19 @@ void WorkerAttachment::shutdownDbb(Database* dbb)
 
 StableAttachmentPart* WorkerAttachment::getAttachment(FbStatusVector* status, Database* dbb)
 {
-	//?? Database::Checkout cout(dbb);
+	// There should be no locked attachment.
+#ifdef _DEBUG
+	thread_db* tdbb = JRD_get_thread_data();
+	if (tdbb)
+	{
+		Attachment* att = tdbb->getAttachment();
+		if (att)
+		{
+			const StableAttachmentPart::Sync* sync = att->getStable()->getSync();
+			fb_assert(!sync || !sync->locked());
+		}
+	}
+#endif
 
 	Arg::Gds(isc_shutdown).copyTo(status);
 
@@ -245,7 +265,6 @@ StableAttachmentPart* WorkerAttachment::getAttachment(FbStatusVector* status, Da
 	if (m_shutdown)
 		return NULL;
 
-
 	FB_SIZE_T maxWorkers = Config::getMaxParallelWorkers();
 	if (maxWorkers <= 0)
 		maxWorkers = MAX_ULONG;
@@ -298,7 +317,10 @@ StableAttachmentPart* WorkerAttachment::getAttachment(FbStatusVector* status, Da
 		fb_assert(!att || (att->att_flags & ATT_worker));
 
 		if (att)
+		{
 			att->att_use_count++;
+			att->setupIdleTimer(true);
+		}
 	}
 
 	if (att)
@@ -319,10 +341,12 @@ void WorkerAttachment::releaseAttachment(FbStatusVector* status, StableAttachmen
 			return;
 
 		att->att_use_count--;
+		att->setupIdleTimer(false);
+
 		item = getByName(att->att_database->dbb_filename);
 	}
 
-	bool detach = (m_shutdown || (item == NULL));
+	const bool detach = (m_shutdown || (item == NULL));
 	bool tryClear = false;
 
 	if (item)
@@ -372,6 +396,36 @@ void WorkerAttachment::clear(bool checkRefs)
 	}
 }
 
+bool WorkerAttachment::detachIdle(StableAttachmentPart* sAtt)
+{
+	WorkerAttachment* item = NULL;
+	{	// scope
+		AttSyncLockGuard attGuard(sAtt->getSync(), FB_FUNCTION);
+
+		Attachment* att = sAtt->getHandle();
+		if (!att || att->att_use_count > 0)
+			return false;
+
+		item = getByName(att->att_database->dbb_filename);
+	}
+
+	if (item)
+	{
+		MutexLockGuard guard(item->m_mutex, FB_FUNCTION);
+
+		FB_SIZE_T pos;
+		if (item->m_idleAtts.find(sAtt, pos))
+			item->m_idleAtts.remove(pos);
+		else
+			return false;
+	}
+
+	FbLocalStatus status;
+	doDetach(&status, sAtt);
+
+	return true;
+}
+
 StableAttachmentPart* WorkerAttachment::doAttach(FbStatusVector* status, Database* dbb)
 {
 	StableAttachmentPart* sAtt = NULL;
@@ -396,7 +450,10 @@ StableAttachmentPart* WorkerAttachment::doAttach(FbStatusVector* status, Databas
 	}
 
 	if (sAtt)
+	{
 		sAtt->addRef(); // !!
+		sAtt->getHandle()->setIdleTimeout(WORKER_IDLE_TIMEOUT);
+	}
 
 	return sAtt;
 }
@@ -415,7 +472,6 @@ void WorkerAttachment::doDetach(FbStatusVector* status, StableAttachmentPart* sA
 	{
 		JAttachment* jAtt = sAtt->getInterface();
 		jAtt->detach(status);
-		jAtt->release();
 	}
 	sAtt->release(); // !!
 }

src/jrd/WorkerAttachment.h

@@ -50,6 +50,9 @@ public:
 
 	void fini();
 
+protected:
+	virtual void doOnIdleTimer(Firebird::TimerImpl* timer);
+
 private:
 	explicit WorkerStableAttachment(FbStatusVector* status, Jrd::Attachment* att);
 	virtual ~WorkerStableAttachment();
@@ -80,6 +83,8 @@ public:
 	static Jrd::StableAttachmentPart* getAttachment(FbStatusVector* status, Jrd::Database* dbb);
 	static void releaseAttachment(FbStatusVector* status, Jrd::StableAttachmentPart* sAtt);
 
+	static bool detachIdle(Jrd::StableAttachmentPart* sAtt);
+
 	static void incUserAtts(const Firebird::PathName& dbname);
 	static void decUserAtts(const Firebird::PathName& dbname);