bzr push into mysql-5.6 branch (aditya.a:4553 to 4554) Bug#14234028

[Aditya A]

 4554 Aditya A	2012-11-08 [merge]
      Bug#14234028 - CRASH DURING SHUTDOWN WITH BACKGROUND PURGE THREAD
       
       Analysis
       --------- 
       
       my_stat() calls stat() and if the stat() call fails we try to set 
       the variable  my_errno which is actually a thread specific data .
       We try to get the  address of this thread specific data using
       my_pthread_getspecifc(),but for the purge thread we have not defined 
       any thread specific data so it returns null and when dereferencing 
       null we get a segmentation fault.
              init_available_charsets() seen in the core stack is invoked 
       through  pthread_once() .pthread_once is used for one time 
       initialization.Since free_charsets() is called before innodb plugin 
       shutdown ,purge thread calls init_avaliable_charsets() which leads 
       to the crash.
      
       Fix
       ---
       Call free_charsets() after the innodb plugin shutdown,since purge 
       threads are still using the charsets. 

    modified:
      sql/mysqld.cc
 4553 Aditya A	2012-11-08 [merge]
      Bug#11751825 - OPTIMIZE PARTITION RECREATES FULL TABLE INSTEAD JUST PARTITION
      
      [NULL MERGE from 5.5 ]

=== modified file 'sql/mysqld.cc'
--- a/sql/mysqld.cc	revid:aditya.a@stripped
+++ b/sql/mysqld.cc	revid:aditya.a@stripped
@@ -1771,7 +1771,6 @@ void clean_up(bool print_message)
   item_user_lock_free();
   lex_free();       /* Free some memory */
   item_create_cleanup();
-  free_charsets();
   if (!opt_noacl)
   {
 #ifdef HAVE_DLOPEN
@@ -1826,6 +1825,7 @@ void clean_up(bool print_message)
   my_atomic_rwlock_destroy(&opt_binlog_max_flush_queue_time_lock);
   my_atomic_rwlock_destroy(&global_query_id_lock);
   my_atomic_rwlock_destroy(&thread_running_lock);
+  free_charsets();
   mysql_mutex_lock(&LOCK_thread_count);
   DBUG_PRINT("quit", ("got thread count lock"));
   ready_to_exit=1;

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