diff --git a/builds/install/misc/firebird.conf b/builds/install/misc/firebird.conf
index c35907338d..4cec7d682b 100644
--- a/builds/install/misc/firebird.conf
+++ b/builds/install/misc/firebird.conf
@@ -611,6 +611,18 @@
 #ConnectionIdleTimeout = 0
 
 
+# ----------------------------
+#
+# Set number of seconds after which ON DISCONNECT trigger execution will be
+# automatically cancelled by the engine. Zero means no timeout is set.
+#
+# Per-database configurable.
+#
+# Type: integer
+#
+#OnDisconnectTriggerTimeout = 180
+
+
 # ----------------------------
 #
 # How often the pages are flushed on disk
diff --git a/src/common/config/config.h b/src/common/config/config.h
index a7b1febc4c..f874213c32 100644
--- a/src/common/config/config.h
+++ b/src/common/config/config.h
@@ -176,6 +176,7 @@ enum ConfigKey
 	KEY_ENCRYPT_SECURITY_DATABASE,
 	KEY_STMT_TIMEOUT,
 	KEY_CONN_IDLE_TIMEOUT,
+	KEY_ON_DISCONNECT_TRIG_TIMEOUT,
 	KEY_CLIENT_BATCH_BUFFER,
 	KEY_OUTPUT_REDIRECTION_FILE,
 	KEY_EXT_CONN_POOL_SIZE,
@@ -284,6 +285,7 @@ constexpr ConfigEntry entries[MAX_CONFIG_KEY] =
 	{TYPE_BOOLEAN,	"AllowEncryptedSecurityDatabase",	false,	false},
 	{TYPE_INTEGER,	"StatementTimeout",			false,	0},
 	{TYPE_INTEGER,	"ConnectionIdleTimeout",	false,	0},
+	{TYPE_INTEGER,	"OnDisconnectTriggerTimeout",	false,	180},
 	{TYPE_INTEGER,	"ClientBatchBuffer",		false,	128 * 1024},
 #ifdef DEV_BUILD
 	{TYPE_STRING,	"OutputRedirectionFile", 	true,	"-"},
@@ -603,6 +605,9 @@ public:
 	// set in minutes
 	CONFIG_GET_PER_DB_KEY(unsigned int, getConnIdleTimeout, KEY_CONN_IDLE_TIMEOUT, getInt);
 
+	// set in seconds
+	CONFIG_GET_PER_DB_KEY(unsigned int, getOnDisconnectTrigTimeout, KEY_ON_DISCONNECT_TRIG_TIMEOUT, getInt);
+
 	CONFIG_GET_PER_DB_KEY(unsigned int, getClientBatchBuffer, KEY_CLIENT_BATCH_BUFFER, getInt);
 
 	CONFIG_GET_GLOBAL_STR(getOutputRedirectionFile, KEY_OUTPUT_REDIRECTION_FILE);
diff --git a/src/jrd/exe.cpp b/src/jrd/exe.cpp
index b9284618d5..b00419452f 100644
--- a/src/jrd/exe.cpp
+++ b/src/jrd/exe.cpp
@@ -1209,7 +1209,19 @@ void EXE_execute_triggers(thread_db* tdbb,
 					&tdbb->getAttachment()->att_original_timezone,
 					tdbb->getAttachment()->att_current_timezone);
 
-				EXE_start(tdbb, trigger, transaction);
+				if (trigger_action == TRIGGER_DISCONNECT)
+				{
+					if (!trigger->req_timer)
+						trigger->req_timer = FB_NEW_POOL(*tdbb->getAttachment()->att_pool) TimeoutTimer();
+
+					const unsigned int timeOut = tdbb->getDatabase()->dbb_config->getOnDisconnectTrigTimeout() * 1000;
+					trigger->req_timer->setup(timeOut, isc_cfg_stmt_timeout);
+					trigger->req_timer->start();
+					thread_db::TimerGuard timerGuard(tdbb, trigger->req_timer, true);
+					EXE_start(tdbb, trigger, transaction);
+				}
+				else
+					EXE_start(tdbb, trigger, transaction);
 			}
 
 			const bool ok = (trigger->req_operation != Request::req_unwind);
diff --git a/src/jrd/jrd.cpp b/src/jrd/jrd.cpp
index bb01a831d8..1fa7cea8ad 100644
--- a/src/jrd/jrd.cpp
+++ b/src/jrd/jrd.cpp
@@ -8200,15 +8200,21 @@ static void purge_attachment(thread_db* tdbb, StableAttachmentPart* sAtt, unsign
 					transaction = TRA_start(tdbb, 0, NULL);
 					attachment->att_flags = save_flags;
 
+					// Allow cancelling while ON DISCONNECT triggers are running
+					tdbb->tdbb_flags &= ~TDBB_detaching;
+
 					// run ON DISCONNECT triggers
 					EXE_execute_db_triggers(tdbb, transaction, TRIGGER_DISCONNECT);
 
+					tdbb->tdbb_flags |= TDBB_detaching;
+
 					// and commit the transaction
 					TRA_commit(tdbb, transaction, false);
 				}
 				catch (const Exception& ex)
 				{
 					attachment->att_flags = save_flags;
+					tdbb->tdbb_flags |= TDBB_detaching;
 
 					string s;
 					s.printf("Database: %s\n\tError at disconnect:", attachment->att_filename.c_str());
@@ -8927,11 +8933,8 @@ ISC_STATUS thread_db::getCancelState(ISC_STATUS* secondary)
 	if (tdbb_flags & (TDBB_verb_cleanup | TDBB_dfw_cleanup | TDBB_detaching | TDBB_wait_cancel_disable))
 		return FB_SUCCESS;
 
-	if (attachment)
+	if (attachment && attachment->att_purge_tid != Thread::getId())
 	{
-		if (attachment->att_purge_tid == Thread::getId())
-			return FB_SUCCESS;
-
 		if (attachment->att_flags & ATT_shutdown)
 		{
 			if (database->dbb_ast_flags & DBB_shutdown)