Correct the value of global memory_used

As a special hack global memory_used isn't SHOW_LONG_STATUS
but still relies on calc_sum_of_all_status() being called.

followup for 63f91927

mysql-test/r/status2.result

@@ -74,4 +74,12 @@ DROP TRIGGER trigg1;
 DROP FUNCTION testQuestion;
 DROP EVENT ev1;
 DROP TABLE t1,t2;
-End of 6.0 tests
+#
+# End of 5.5 tests
+#
+select variable_value < 1024*1024*1024 from information_schema.global_status where variable_name='memory_used';
+variable_value < 1024*1024*1024
+1
+#
+# End of 10.2 tests
+#

mysql-test/t/status2.test

@@ -64,5 +64,14 @@ DROP TRIGGER trigg1;
 DROP FUNCTION testQuestion;
 DROP EVENT ev1;
 DROP TABLE t1,t2;
---echo End of 6.0 tests
+
+--echo #
+--echo # End of 5.5 tests
+--echo #
+
+select variable_value < 1024*1024*1024 from information_schema.global_status where variable_name='memory_used';
+
+--echo #
+--echo # End of 10.2 tests
+--echo #
 

sql/mysqld.cc

@@ -8441,8 +8441,11 @@ static int show_memory_used(THD *thd, SHOW_VAR *var, char *buff,
   var->type= SHOW_LONGLONG;
   var->value= buff;
   if (scope == OPT_GLOBAL)
+  {
+    calc_sum_of_all_status_if_needed(status_var);
     *(longlong*) buff= (status_var->global_memory_used +
                         status_var->local_memory_used);
+  }
   else
     *(longlong*) buff= status_var->local_memory_used;
   return 0;

sql/sql_class.h

@@ -865,11 +865,24 @@ void add_to_status(STATUS_VAR *to_var, STATUS_VAR *from_var);
 void add_diff_to_status(STATUS_VAR *to_var, STATUS_VAR *from_var,
                         STATUS_VAR *dec_var);
 
+uint calc_sum_of_all_status(STATUS_VAR *to);
+static inline void calc_sum_of_all_status_if_needed(STATUS_VAR *to)
+{
+  if (to->local_memory_used == 0)
+  {
+    mysql_mutex_lock(&LOCK_status);
+    *to= global_status_var;
+    mysql_mutex_unlock(&LOCK_status);
+    calc_sum_of_all_status(to);
+    DBUG_ASSERT(to->local_memory_used);
+  }
+}
+
 /*
   Update global_memory_used. We have to do this with atomic_add as the
   global value can change outside of LOCK_status.
 */
-inline void update_global_memory_status(int64 size)
+static inline void update_global_memory_status(int64 size)
 {
   DBUG_PRINT("info", ("global memory_used: %lld  size: %lld",
                       (longlong) global_status_var.global_memory_used,
@@ -887,7 +900,7 @@ inline void update_global_memory_status(int64 size)
   @retval         NULL on error
   @retval         Pointter to CHARSET_INFO with the given name on success
 */
-inline CHARSET_INFO *
+static inline CHARSET_INFO *
 mysqld_collation_get_by_name(const char *name,
                              CHARSET_INFO *name_cs= system_charset_info)
 {
@@ -906,7 +919,7 @@ mysqld_collation_get_by_name(const char *name,
   return cs;
 }
 
-inline bool is_supported_parser_charset(CHARSET_INFO *cs)
+static inline bool is_supported_parser_charset(CHARSET_INFO *cs)
 {
   return MY_TEST(cs->mbminlen == 1);
 }

sql/sql_show.cc

@@ -3580,15 +3580,8 @@ static bool show_status_array(THD *thd, const char *wild,
 
         if (show_type == SHOW_SYS)
           mysql_mutex_lock(&LOCK_global_system_variables);
-        else if (show_type >= SHOW_LONG_STATUS && scope == OPT_GLOBAL &&
-                 !status_var->local_memory_used)
-        {
-          mysql_mutex_lock(&LOCK_status);
-          *status_var= global_status_var;
-          mysql_mutex_unlock(&LOCK_status);
-          calc_sum_of_all_status(status_var);
-          DBUG_ASSERT(status_var->local_memory_used);
-        }
+        else if (show_type >= SHOW_LONG_STATUS && scope == OPT_GLOBAL)
+          calc_sum_of_all_status_if_needed(status_var);
 
         pos= get_one_variable(thd, var, scope, show_type, status_var,
                               &charset, buff, &length);