diff --git a/storage/innobase/include/os0thread.h b/storage/innobase/include/os0thread.h
index 9a1ada8..f17be67 100644
--- a/storage/innobase/include/os0thread.h
+++ b/storage/innobase/include/os0thread.h
@@ -117,14 +117,27 @@ os_thread_create_func(
 	os_thread_id_t*		thread_id);	/*!< out: id of the created
 						thread, or NULL */
 
+/**
+Waits until the specified thread completes and joins it. Its return value is
+ignored.
+
+@param	thread	thread to join */
+UNIV_INTERN
+void
+os_thread_join(
+	os_thread_t	thread);
+
 /*****************************************************************//**
 Exits the current thread. */
 UNIV_INTERN
 void
 os_thread_exit(
 /*===========*/
-	void*	exit_value)	/*!< in: exit value; in Windows this void*
+	void*	exit_value,	/*!< in: exit value; in Windows this void*
 				is cast as a DWORD */
+	bool	detach = true)	/*!< in: if true, the thread will be detached
+				right before exiting. If false, another thread
+				is responsible for joining this thread. */
 	UNIV_COLD MY_ATTRIBUTE((noreturn));
 /*****************************************************************//**
 Returns the thread identifier of current thread.
diff --git a/storage/innobase/os/os0thread.cc b/storage/innobase/os/os0thread.cc
index 7723362..48a2ebf 100644
--- a/storage/innobase/os/os0thread.cc
+++ b/storage/innobase/os/os0thread.cc
@@ -191,14 +191,33 @@ os_thread_create_func(
 #endif
 }
 
+/**
+Waits until the specified thread completes and joins it. Its return value is
+ignored.
+
+@param	thread	thread to join */
+UNIV_INTERN
+void
+os_thread_join(
+	os_thread_t	thread)
+{
+	int ret	MY_ATTRIBUTE((unused)) = pthread_join(thread, NULL);
+
+	/* Waiting on already-quit threads is allowed */
+	ut_ad(ret == 0 || ret == ESRCH);
+}
+
 /*****************************************************************//**
 Exits the current thread. */
 UNIV_INTERN
 void
 os_thread_exit(
 /*===========*/
-	void*	exit_value)	/*!< in: exit value; in Windows this void*
+	void*	exit_value,	/*!< in: exit value; in Windows this void*
 				is cast as a DWORD */
+	bool	detach)		/*!< in: if true, the thread will be detached
+				right before exiting. If false, another thread
+				is responsible for joining this thread. */
 {
 #ifdef UNIV_DEBUG_THREAD_CREATION
 	fprintf(stderr, "Thread exits, id %lu\n",
@@ -216,7 +235,8 @@ os_thread_exit(
 #ifdef __WIN__
 	ExitThread((DWORD) exit_value);
 #else
-	pthread_detach(pthread_self());
+	if (detach)
+		pthread_detach(pthread_self());
 	pthread_exit(exit_value);
 #endif
 }
diff --git a/storage/innobase/row/row0ftsort.cc b/storage/innobase/row/row0ftsort.cc
index 4fd3a51..7d3fcf6 100644
--- a/storage/innobase/row/row0ftsort.cc
+++ b/storage/innobase/row/row0ftsort.cc
@@ -957,7 +957,7 @@ fts_parallel_merge(
 	CloseHandle(psort_info->thread_hdl);
 #endif /*__WIN__ */
 
-	os_thread_exit(NULL);
+	os_thread_exit(NULL, false);
 
 	OS_THREAD_DUMMY_RETURN;
 }
diff --git a/storage/innobase/row/row0merge.cc b/storage/innobase/row/row0merge.cc
index c094be8..0028123 100644
--- a/storage/innobase/row/row0merge.cc
+++ b/storage/innobase/row/row0merge.cc
@@ -3774,6 +3774,13 @@ wait_again:
 						" exited when creating FTS"
 						" index '%s'",
 						indexes[i]->name);
+				} else {
+					for (j = 0; j < FTS_NUM_AUX_INDEX;
+					     j++) {
+
+					    os_thread_join(merge_info[j]
+							   .thread_hdl);
+					}
 				}
 			} else {
 				/* This cannot report duplicates; an