Improve comments around FLUSH STATUS

It's not possible to flush the global status variables in 5.0
Update test case so it works by recording the value of handle_rollback
before and compare it to the value after


mysql-test/r/innodb_mysql.result:
  Update result file
mysql-test/t/innodb_mysql.test:
  It's not possible to reset the global status variables in 5.0 so intead its value
  is recorded and compared to the after value.
  It should not have changed.
sql/mysqld.cc:
  Improve comments
sql/set_var.cc:
  Improve comments
sql/sql_class.cc:
  Improve comments
sql/sql_class.h:
  Improve comments

1 files changed, 9 insertions, 1 deletions

diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 1dd15398cd1..c84e1f7ee56 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -5997,6 +5997,10 @@ The minimum value for this variable is 4096.",
 };
 
 
+/*
+  Variables shown by SHOW STATUS in alphabetical order
+*/
+
 struct show_var_st status_vars[]= {
   {"Aborted_clients",          (char*) &aborted_threads,        SHOW_LONG},
   {"Aborted_connects",         (char*) &aborted_connects,       SHOW_LONG},
@@ -7466,15 +7470,19 @@ void refresh_status(THD *thd)
 {
   pthread_mutex_lock(&LOCK_status);
 
-  /* We must update the global status before cleaning up the thread */
+  /* Add thread's status variabes to global status */
   add_to_status(&global_status_var, &thd->status_var);
+
+  /* Reset thread's status variables */
   bzero((char*) &thd->status_var, sizeof(thd->status_var));
 
+  /* Reset some global variables */
   for (struct show_var_st *ptr=status_vars; ptr->name; ptr++)
   {
     if (ptr->type == SHOW_LONG)
       *(ulong*) ptr->value= 0;
   }
+
   /* Reset the counters of all key caches (default and named). */
   process_key_caches(reset_key_cache_counters);
   pthread_mutex_unlock(&LOCK_status);