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




client/mysql.cc:
  sql_protocol_typelib is not exported from libmysqld
  (does not make sense either)
  thus excluded from embedded client
dbug/dbug.c:
  revert changes for Bug#38293
include/my_dbug.h:
  revert changes for Bug#38293
libmysql/libmysql.c:
  Removed DBUG_POP call, because when called after my_end(), will access
  THR_key_mysys that is already deleted. The result of pthread_get_specific
  is not predictable in this case and hence DBUG_POP can crash.
libmysqld/examples/CMakeLists.txt:
  Revert changes for Bug#38293.
libmysqld/lib_sql.cc:
  code to start handle manager is factored out into 
  start_handle_manager() function
libmysqld/libmysqld.def:
  Revert changes for Bug #38293
  Remove excessive exports from libmysqld, export what API documents.
mysys/my_thr_init.c:
  Remove windows-DLL-specific workaround for something (old code, no documentation for
  what specifically). The problem is that even after my_thread_end() is finished, 
  DBUG statement can initiate my_thread_init(). This does not happen anywhere else and 
  should not happen on  Windows either.
sql/mysql_priv.h:
  - new functions start_handle_manager() and stop_handle_manager()
  - move manager_thread_in_use  variable to sql_manager.cc and made
  it static
  - remove manager_status, as it is unused
sql/mysqld.cc:
  Code to start/stop handle_manager thread is factored out into start_handle_manager()

3 files changed, 5 insertions, 135 deletions

diff --git a/libmysqld/examples/CMakeLists.txt b/libmysqld/examples/CMakeLists.txt
index 137dd11d28e..346278425a7 100644
--- a/libmysqld/examples/CMakeLists.txt
+++ b/libmysqld/examples/CMakeLists.txt
@@ -29,13 +29,13 @@ ADD_DEFINITIONS(-DEMBEDDED_LIBRARY)
 ADD_EXECUTABLE(mysql_embedded ../../client/completion_hash.cc
                ../../client/mysql.cc ../../client/readline.cc
                ../../client/sql_string.cc)
-TARGET_LINK_LIBRARIES(mysql_embedded wsock32)
+TARGET_LINK_LIBRARIES(mysql_embedded debug dbug strings mysys vio yassl taocrypt regex ws2_32)
 ADD_DEPENDENCIES(mysql_embedded libmysqld)
 
 ADD_EXECUTABLE(mysqltest_embedded ../../client/mysqltest.c)
-TARGET_LINK_LIBRARIES(mysqltest_embedded wsock32)
+TARGET_LINK_LIBRARIES(mysqltest_embedded debug dbug strings mysys vio yassl taocrypt regex ws2_32)
 ADD_DEPENDENCIES(mysqltest_embedded libmysqld)
 
 ADD_EXECUTABLE(mysql_client_test_embedded ../../tests/mysql_client_test.c)
-TARGET_LINK_LIBRARIES(mysql_client_test_embedded wsock32)
+TARGET_LINK_LIBRARIES(mysql_client_test_embedded debug dbug strings mysys vio yassl taocrypt regex ws2_32)
 ADD_DEPENDENCIES(mysql_client_test_embedded libmysqld)
diff --git a/libmysqld/lib_sql.cc b/libmysqld/lib_sql.cc
index e78c656d565..23572ad4929 100644
--- a/libmysqld/lib_sql.cc
+++ b/libmysqld/lib_sql.cc
@@ -386,6 +386,7 @@ static void emb_free_embedded_thd(MYSQL *mysql)
   thd->store_globals();
   thd->unlink();
   delete thd;
+  my_pthread_setspecific_ptr(THR_THD,  0);
   mysql->thd=0;
 }
 
@@ -539,12 +540,7 @@ int init_embedded_server(int argc, char **argv, char **groups)
 
   (void) thr_setconcurrency(concurrency);	// 10 by default
 
-  if (flush_time && flush_time != ~(ulong) 0L)
-  {
-    pthread_t hThread;
-    if (pthread_create(&hThread,&connection_attrib,handle_manager,0))
-      sql_print_error("Warning: Can't create thread to manage maintenance");
-  }
+  start_handle_manager();
 
   // FIXME initialize binlog_filter and rpl_filter if not already done
   //       corresponding delete is in clean_up()
diff --git a/libmysqld/libmysqld.def b/libmysqld/libmysqld.def
index 865475cb56c..047cfe0fe57 100644
--- a/libmysqld/libmysqld.def
+++ b/libmysqld/libmysqld.def
@@ -2,94 +2,6 @@ LIBRARY		LIBMYSQLD
 DESCRIPTION	'MySQL 5.1 Embedded Server Library'
 VERSION		5.1
 EXPORTS
-	_db_process_
-	_db_enter_
-	_db_return_
-	_db_push_
-	_db_doprnt_
-	_db_pargs_
-	strnmov
-	get_charset
-	my_memmem
-	my_snprintf
-	pthread_exit
-	pthread_cond_signal
-	dynstr_append_mem
-	init_dynamic_string
-	dynstr_free
-	my_hash_free
-	my_vsnprintf
-	dynstr_append
-	my_close
-	my_open
-	dynstr_set
-	dynstr_append_os_quoted
-	my_delete
-	my_seek
-	my_write
-	create_temp_file
-	fn_format
-	dirname_part
-	my_hash_insert
-	my_hash_search
-	test_if_hard_path
-	my_copy
-	my_mkdir
-	my_sleep
-	my_strtod
-	pthread_cond_wait
-	my_strnncoll_simple
-	get_dynamic
-	my_regerror
-	init_dynamic_array2
-	pthread_create
-	pthread_cond_init
-	my_regcomp
-	my_regexec
-	my_regex_end
-	my_regfree
-	longlong2str
-	my_set_exception_pointers
-	my_print_stacktrace
-	my_thread_stack_size
-	my_safe_print_str
-	my_stat
-	_my_hash_init
-	pthread_attr_setstacksize
-	pthread_attr_init
-	my_dirend
-	wild_compare
-	my_dir
-	my_micro_time
-	find_type_or_exit
-	_dig_vec_upper
-	_dig_vec_lower
-	bmove_upp
-	delete_dynamic
-	free_defaults
-	getopt_compare_strings
-	getopt_ull_limit_value
-	handle_options
-	init_dynamic_array
-	insert_dynamic
-	int2str
-	is_prefix
-	list_add
-	list_delete
-	load_defaults
-	max_allowed_packet
-	my_cgets
-	my_end
-	my_getopt_print_errors
-	my_init
-	my_malloc
-	my_memdup
-	my_no_flags_free
-	my_path
-	my_print_help
-	my_print_variables
-	my_realloc
-	my_strdup
 	mysql_thread_end
 	mysql_thread_init
 	myodbc_remove_escape
@@ -162,47 +74,13 @@ EXPORTS
 	mysql_thread_safe
 	mysql_use_result
 	mysql_warning_count
-	set_dynamic
-	strcend
-	strcont
-	strdup_root
-	strfill
-	strinstr
-	strmake
-	strmov
-	strxmov
 	mysql_server_end
 	mysql_server_init
 	get_tty_password
-	sql_protocol_typelib
 	mysql_get_server_version
 	mysql_set_character_set
 	mysql_sqlstate
-	charsets_dir
-	disabled_my_option
-	my_charset_latin1
-	init_alloc_root
-	my_progname
-	get_charset_name
-	get_charset_by_csname
-	print_defaults
-	find_type
-	strxnmov
-	strend
-	my_fopen
-	my_fclose
-	unpack_filename
-	str2int
-	int10_to_str
-	longlong10_to_str
-	my_snprintf_8bit
-	alloc_root
-	free_root
-	my_read
-	llstr
 	mysql_get_parameters
-	mysql_thread_init
-	mysql_thread_end
 	mysql_stmt_bind_param
 	mysql_stmt_bind_result
 	mysql_stmt_execute
@@ -230,7 +108,3 @@ EXPORTS
 	mysql_stmt_attr_get
 	mysql_stmt_attr_set
 	mysql_stmt_field_count
-	get_defaults_options
-	my_charset_bin
-	my_charset_same
-	modify_defaults_file