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			124 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			124 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| #ifndef INCLUDES_MYSQL_INSTANCE_MANAGER_GUARDIAN_H
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| #define INCLUDES_MYSQL_INSTANCE_MANAGER_GUARDIAN_H
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| /* Copyright (C) 2004 MySQL AB
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| 
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|    This program is free software; you can redistribute it and/or modify
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|    it under the terms of the GNU General Public License as published by
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|    the Free Software Foundation; either version 2 of the License, or
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|    (at your option) any later version.
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| 
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|    This program is distributed in the hope that it will be useful,
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|    but WITHOUT ANY WARRANTY; without even the implied warranty of
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|    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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|    GNU General Public License for more details.
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| 
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|    You should have received a copy of the GNU General Public License
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|    along with this program; if not, write to the Free Software
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|    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
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| 
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| #include <my_global.h>
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| #include "thread_registry.h"
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| 
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| #include <my_sys.h>
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| #include <my_list.h>
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| 
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| #if defined(__GNUC__) && defined(USE_PRAGMA_INTERFACE)
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| #pragma interface
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| #endif
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| 
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| class Instance;
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| class Instance_map;
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| class Thread_registry;
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| struct GUARD_NODE;
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| 
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| pthread_handler_t guardian(void *arg);
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| 
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| struct Guardian_thread_args
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| {
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|   Thread_registry &thread_registry;
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|   Instance_map *instance_map;
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|   int monitoring_interval;
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| 
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|   Guardian_thread_args(Thread_registry &thread_registry_arg,
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|                        Instance_map *instance_map_arg,
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|                        uint monitoring_interval_arg) :
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|     thread_registry(thread_registry_arg),
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|     instance_map(instance_map_arg),
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|     monitoring_interval(monitoring_interval_arg)
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|   {}
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| };
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| 
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| 
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| /*
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|   The guardian thread is responsible for monitoring and restarting of guarded
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|   instances.
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| */
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| 
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| class Guardian_thread: public Guardian_thread_args
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| {
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| public:
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|   /* states of an instance */
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|   enum enum_instance_state { NOT_STARTED= 1, STARTING, STARTED, JUST_CRASHED,
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|                              CRASHED, CRASHED_AND_ABANDONED, STOPPING };
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| 
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|   /*
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|     The Guardian list node structure. Guardian utilizes it to store
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|     guarded instances plus some additional info.
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|   */
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| 
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|   struct GUARD_NODE
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|   {
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|     Instance *instance;
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|     /* state of an instance (i.e. STARTED, CRASHED, etc.) */
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|     enum_instance_state state;
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|     /* the amount of attemts to restart instance (cleaned up at success) */
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|     int restart_counter;
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|     /* triggered at a crash */
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|     time_t crash_moment;
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|     /* General time field. Used to provide timeouts (at shutdown and restart) */
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|     time_t last_checked;
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|   };
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| 
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| 
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|   Guardian_thread(Thread_registry &thread_registry_arg,
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|                   Instance_map *instance_map_arg,
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|                   uint monitoring_interval_arg);
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|   ~Guardian_thread();
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|   /* Main funtion of the thread */
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|   void run();
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|   /* Initialize or refresh the list of guarded instances */
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|   int init();
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|   /* Request guardian shutdown. Stop instances if needed */
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|   void request_shutdown(bool stop_instances);
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|   /* Start instance protection */
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|   int guard(Instance *instance, bool nolock= FALSE);
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|   /* Stop instance protection */
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|   int stop_guard(Instance *instance);
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|   /* Returns true if guardian thread is stopped */
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|   int is_stopped();
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|   void lock();
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|   void unlock();
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| 
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| public:
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|   pthread_cond_t COND_guardian;
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| 
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| private:
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|   /* Prepares Guardian shutdown. Stops instances is needed */
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|   int stop_instances(bool stop_instances_arg);
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|   /* check instance state and act accordingly */
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|   void process_instance(Instance *instance, GUARD_NODE *current_node,
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|                         LIST **guarded_instances, LIST *elem);
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|   int stopped;
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| 
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| private:
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|   pthread_mutex_t LOCK_guardian;
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|   Thread_info thread_info;
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|   LIST *guarded_instances;
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|   MEM_ROOT alloc;
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|   enum { MEM_ROOT_BLOCK_SIZE= 512 };
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|   /* this variable is set to TRUE when we want to stop Guardian thread */
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|   bool shutdown_requested;
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| };
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| 
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| #endif /* INCLUDES_MYSQL_INSTANCE_MANAGER_GUARDIAN_H */
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