diff --git a/src/common/classes/ImplementHelper.h b/src/common/classes/ImplementHelper.h
index cd2b28a128..34a7638977 100644
--- a/src/common/classes/ImplementHelper.h
+++ b/src/common/classes/ImplementHelper.h
@@ -313,7 +313,7 @@ public:
 	typedef void VoidNoParam();
 
 	explicit UnloadDetectorHelper(MemoryPool&)
-		: cleanup(NULL), flagOsUnload(false)
+		: cleanup(NULL), thdDetach(NULL), flagOsUnload(false)
 	{ }
 
 	void registerMe()
@@ -348,6 +348,11 @@ public:
 		cleanup = function;
 	}
 
+	void setThreadDetach(VoidNoParam* function)
+	{
+		thdDetach = function;
+	}
+
 	void doClean()
 	{
 		flagOsUnload = false;
@@ -359,8 +364,15 @@ public:
 		}
 	}
 
+	void threadDetach()
+	{
+		if (thdDetach)
+			thdDetach();
+	}
+
 private:
 	VoidNoParam* cleanup;
+	VoidNoParam* thdDetach;
 	bool flagOsUnload;
 };
 
diff --git a/src/include/firebird/FirebirdInterface.idl b/src/include/firebird/FirebirdInterface.idl
index d35ba75599..5a7c78e944 100644
--- a/src/include/firebird/FirebirdInterface.idl
+++ b/src/include/firebird/FirebirdInterface.idl
@@ -213,6 +213,10 @@ interface PluginFactory : Versioned
 interface PluginModule : Versioned
 {
 	void doClean();
+
+version:		// 3.0.3 => 3.0.4
+	// Used to release resources allocated per-thread 
+	void threadDetach();
 }
 
 // Interface to deal with plugins here and there, returned by master interface
diff --git a/src/include/firebird/IdlFbInterfaces.h b/src/include/firebird/IdlFbInterfaces.h
index e9f879bd35..25ec6969e8 100644
--- a/src/include/firebird/IdlFbInterfaces.h
+++ b/src/include/firebird/IdlFbInterfaces.h
@@ -736,6 +736,7 @@ namespace Firebird
 		struct VTable : public IVersioned::VTable
 		{
 			void (CLOOP_CARG *doClean)(IPluginModule* self) throw();
+			void (CLOOP_CARG *threadDetach)(IPluginModule* self) throw();
 		};
 
 	protected:
@@ -749,12 +750,21 @@ namespace Firebird
 		}
 
 	public:
-		static const unsigned VERSION = 2;
+		static const unsigned VERSION = 3;
 
 		void doClean()
 		{
 			static_cast<VTable*>(this->cloopVTable)->doClean(this);
 		}
+
+		void threadDetach()
+		{
+			if (cloopVTable->version < 3)
+			{
+				return;
+			}
+			static_cast<VTable*>(this->cloopVTable)->threadDetach(this);
+		}
 	};
 
 	class IPluginManager : public IVersioned
@@ -7004,6 +7014,7 @@ namespace Firebird
 				{
 					this->version = Base::VERSION;
 					this->doClean = &Name::cloopdoCleanDispatcher;
+					this->threadDetach = &Name::cloopthreadDetachDispatcher;
 				}
 			} vTable;
 
@@ -7021,6 +7032,18 @@ namespace Firebird
 				StatusType::catchException(0);
 			}
 		}
+
+		static void CLOOP_CARG cloopthreadDetachDispatcher(IPluginModule* self) throw()
+		{
+			try
+			{
+				static_cast<Name*>(self)->Name::threadDetach();
+			}
+			catch (...)
+			{
+				StatusType::catchException(0);
+			}
+		}
 	};
 
 	template <typename Name, typename StatusType, typename Base = IVersionedImpl<Name, StatusType, Inherit<IPluginModule> > >
@@ -7037,6 +7060,7 @@ namespace Firebird
 		}
 
 		virtual void doClean() = 0;
+		virtual void threadDetach() = 0;
 	};
 
 	template <typename Name, typename StatusType, typename Base>
diff --git a/src/jrd/jrd.cpp b/src/jrd/jrd.cpp
index b8bd36655e..7961b353bf 100644
--- a/src/jrd/jrd.cpp
+++ b/src/jrd/jrd.cpp
@@ -426,9 +426,12 @@ static Static<EngineFactory> engineFactory;
 
 void registerEngine(IPluginManager* iPlugin)
 {
-	getUnloadDetector()->setCleanup(shutdownBeforeUnload);
+	UnloadDetectorHelper* module = getUnloadDetector();
+	module->setCleanup(shutdownBeforeUnload);
+	module->setThreadDetach(threadDetach);
+
 	iPlugin->registerPluginFactory(IPluginManager::TYPE_PROVIDER, CURRENT_ENGINE, &engineFactory);
-	getUnloadDetector()->registerMe();
+	module->registerMe();
 }
 
 } // namespace Jrd
diff --git a/src/yvalve/PluginManager.cpp b/src/yvalve/PluginManager.cpp
index ee5c83622b..34dcf4543a 100644
--- a/src/yvalve/PluginManager.cpp
+++ b/src/yvalve/PluginManager.cpp
@@ -389,6 +389,14 @@ namespace
 			}
 		}
 
+		void threadDetach()
+		{
+			if (cleanup)
+				cleanup->threadDetach();
+			if (next)
+				next->threadDetach();
+		}
+
 	private:
 		~PluginModule()
 		{
@@ -492,8 +500,6 @@ namespace
 
 		IPluginBase* factory(IFirebirdConf *iFirebirdConf);
 
-		~ConfiguredPlugin();
-
 		const char* getPlugName()
 		{
 			return plugName.c_str();
@@ -519,6 +525,8 @@ namespace
 		int release();
 
 	private:
+		~ConfiguredPlugin();
+
 		RefPtr<PluginModule> module;
 		unsigned int regPlugin;
 		RefPtr<ConfigFile> pluginLoaderConfig;
@@ -682,6 +690,8 @@ namespace
 
 	ConfiguredPlugin::~ConfiguredPlugin()
 	{
+		MutexLockGuard g(plugins->mutex, FB_FUNCTION);
+
 		if (!destroyingPluginsMap)
 		{
 			plugins->remove(MapKey(module->getPlugin(regPlugin).type, plugName));
@@ -718,8 +728,6 @@ namespace
 
 	int ConfiguredPlugin::release()
 	{
-		MutexLockGuard g(plugins->mutex, FB_FUNCTION);
-
 		int x = --refCounter;
 
 #ifdef DEBUG_PLUGINS
@@ -1172,6 +1180,13 @@ void PluginManager::waitForType(unsigned int typeThatMustGoAway)
 	}
 }
 
+void PluginManager::threadDetach()
+{
+	MutexLockGuard g(plugins->mutex, FB_FUNCTION);
+	modules->threadDetach();
+}
+
+
 }	// namespace Firebird
 
 namespace {
diff --git a/src/yvalve/PluginManager.h b/src/yvalve/PluginManager.h
index 3d7052ae85..3b901a98a3 100644
--- a/src/yvalve/PluginManager.h
+++ b/src/yvalve/PluginManager.h
@@ -54,6 +54,7 @@ public:
 
 	static void shutdown();
 	static void waitForType(unsigned int typeThatMustGoAway);
+	static void threadDetach();
 };
 
 }	// namespace Firebird
diff --git a/src/yvalve/utl.cpp b/src/yvalve/utl.cpp
index 912210e649..b16b1a070b 100644
--- a/src/yvalve/utl.cpp
+++ b/src/yvalve/utl.cpp
@@ -56,6 +56,7 @@
 #include "../yvalve/YObjects.h"
 #include "../yvalve/why_proto.h"
 #include "../yvalve/prepa_proto.h"
+#include "../yvalve/PluginManager.h"
 #include "../jrd/constants.h"
 #include "../jrd/build_no.h"
 #include "../common/classes/ClumpletWriter.h"
@@ -3172,6 +3173,7 @@ void ThreadCleanup::initThreadCleanup()
 void ThreadCleanup::finiThreadCleanup()
 {
 	pthread_setspecific(key, NULL);
+	PluginManager::threadDetach();
 }
 
 
@@ -3204,6 +3206,7 @@ void ThreadCleanup::initThreadCleanup()
 
 void ThreadCleanup::finiThreadCleanup()
 {
+	PluginManager::threadDetach();
 }
 #endif // #ifdef WIN_NT