diff --git a/src/jrd/Database.h b/src/jrd/Database.h
index 3d6f730dad..02ffb6452a 100644
--- a/src/jrd/Database.h
+++ b/src/jrd/Database.h
@@ -253,8 +253,11 @@ public:
 		CheckoutLockGuard(Database* dbb, Firebird::Mutex& m)
 			: mutex(m)
 		{
-			Checkout dcoHolder(dbb);
-			mutex.enter();
+			if (!mutex.tryEnter())
+			{
+				Checkout dcoHolder(dbb);
+				mutex.enter();
+			}
 		}
 
 		~CheckoutLockGuard()
diff --git a/src/jrd/jrd.cpp b/src/jrd/jrd.cpp
index ed81a32940..5740792e96 100644
--- a/src/jrd/jrd.cpp
+++ b/src/jrd/jrd.cpp
@@ -174,6 +174,9 @@ namespace
 
 	inline void validateHandle(thread_db* tdbb, Jrd::Attachment* const attachment)
 	{
+		if (attachment == tdbb->getAttachment())
+			return;
+
 		if (!attachment->checkHandle() || !attachment->att_database->checkHandle())
 		{
 			status_exception::raise(Arg::Gds(isc_bad_db_handle));