Bug#38522: 5 seconds delay when closing application using embedded server

                  
The problem here is that embedded server starts handle_thread manager 
thread  on mysql_library_init() does not stop it on mysql_library_end().
At shutdown, my_thread_global_end() waits for thread count to become 0,
but since we did not stop the thread it will give up after 5 seconds.
             
Solution is to move shutdown for handle_manager thread from kill_server()
(mysqld specific) to clean_up() that is used by both embedded and mysqld.
            
This patch also contains some refactorings - to avoid duplicate code,
start_handle_manager() and stop_handle_manager() functions are introduced.
Unused variables are eliminated. handle_manager does not rely on global
variable abort_loop anymore to stop (abort_loop is not set for embedded).
            
Note: Specifically on Windows and when using DBUG version of libmysqld, 
the complete solution requires removing obsolete code my_thread_init() 
from my_thread_var(). This has a side effect that a DBUG statement 
after my_thread_end() can cause thread counter to be incremented, and 
embedded will hang for some seconds. Or worse, my_thread_init() will 
crash if critical sections have been deleted by the global cleanup 
routine that runs in a different thread. 

This patch also fixes and revert prior changes for Bug#38293 
"Libmysqld crash in mysql_library_init if language file missing".

Root cause of the crash observed in Bug#38293  was bug in my_thread_init() 
described above

1 files changed, 1 insertions, 11 deletions

diff --git a/mysys/my_thr_init.c b/mysys/my_thr_init.c
index 933674fa007..2278c467f32 100644
--- a/mysys/my_thr_init.c
+++ b/mysys/my_thr_init.c
@@ -368,17 +368,7 @@ void my_thread_end(void)
 
 struct st_my_thread_var *_my_thread_var(void)
 {
-  struct st_my_thread_var *tmp=
-    my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
-#if defined(USE_TLS)
-  /* This can only happen in a .DLL */
-  if (!tmp)
-  {
-    my_thread_init();
-    tmp=my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
-  }
-#endif
-  return tmp;
+  return  my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
 }