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  • Committer: Bazaar Package Importer
  • Author(s): Norbert Tretkowski
  • Date: 2010-03-17 14:56:02 UTC
  • Revision ID: james.westby@ubuntu.com-20100317145602-x7e30l1b2sb5s6w6
Tags: upstream-5.1.45
Import upstream version 5.1.45

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include/thr_lock.h
 
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/* Copyright 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc.
 
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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; version 2 of the License.
 
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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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   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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/* For use with thr_lock:s */
 
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#ifndef _thr_lock_h
 
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#define _thr_lock_h
 
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#ifdef  __cplusplus
 
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extern "C" {
 
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#endif
 
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#include <my_pthread.h>
 
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#include <my_list.h>
 
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struct st_thr_lock;
 
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extern ulong locks_immediate,locks_waited ;
 
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/*
 
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  Important: if a new lock type is added, a matching lock description
 
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             must be added to sql_test.cc's lock_descriptions array.
 
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*/
 
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enum thr_lock_type { TL_IGNORE=-1,
 
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                     TL_UNLOCK,                 /* UNLOCK ANY LOCK */
 
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                     /*
 
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                       Parser only! At open_tables() becomes TL_READ or
 
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                       TL_READ_NO_INSERT depending on the binary log format
 
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                       (SBR/RBR) and on the table category (log table).
 
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                       Used for tables that are read by statements which
 
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                       modify tables.
 
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                     */
 
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                     TL_READ_DEFAULT,
 
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                     TL_READ,                   /* Read lock */
 
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                     TL_READ_WITH_SHARED_LOCKS,
 
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                     /* High prior. than TL_WRITE. Allow concurrent insert */
 
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                     TL_READ_HIGH_PRIORITY,
 
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                     /* READ, Don't allow concurrent insert */
 
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                     TL_READ_NO_INSERT,
 
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                     /* 
 
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                        Write lock, but allow other threads to read / write.
 
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                        Used by BDB tables in MySQL to mark that someone is
 
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                        reading/writing to the table.
 
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                      */
 
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                     TL_WRITE_ALLOW_WRITE,
 
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                     /*
 
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                        Write lock, but allow other threads to read.
 
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                        Used by ALTER TABLE in MySQL to allow readers
 
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                        to use the table until ALTER TABLE is finished.
 
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                     */
 
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                     TL_WRITE_ALLOW_READ,
 
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                     /*
 
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                       WRITE lock used by concurrent insert. Will allow
 
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                       READ, if one could use concurrent insert on table.
 
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                     */
 
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                     TL_WRITE_CONCURRENT_INSERT,
 
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                     /* Write used by INSERT DELAYED.  Allows READ locks */
 
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                     TL_WRITE_DELAYED,
 
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                     /* 
 
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                       parser only! Late bound low_priority flag. 
 
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                       At open_tables() becomes thd->update_lock_default.
 
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                     */
 
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                     TL_WRITE_DEFAULT,
 
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                     /* WRITE lock that has lower priority than TL_READ */
 
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                     TL_WRITE_LOW_PRIORITY,
 
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                     /* Normal WRITE lock */
 
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                     TL_WRITE,
 
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                     /* Abort new lock request with an error */
 
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                     TL_WRITE_ONLY};
 
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enum enum_thr_lock_result { THR_LOCK_SUCCESS= 0, THR_LOCK_ABORTED= 1,
 
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                            THR_LOCK_WAIT_TIMEOUT= 2, THR_LOCK_DEADLOCK= 3 };
 
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extern ulong max_write_lock_count;
 
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extern ulong table_lock_wait_timeout;
 
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extern my_bool thr_lock_inited;
 
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extern enum thr_lock_type thr_upgraded_concurrent_insert_lock;
 
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/*
 
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  A description of the thread which owns the lock. The address
 
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  of an instance of this structure is used to uniquely identify the thread.
 
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*/
 
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typedef struct st_thr_lock_info
 
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{
 
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  pthread_t thread;
 
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  my_thread_id thread_id;
 
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  ulong n_cursors;
 
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} THR_LOCK_INFO;
 
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/*
 
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  Lock owner identifier. Globally identifies the lock owner within the
 
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  thread and among all the threads. The address of an instance of this
 
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  structure is used as id.
 
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*/
 
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typedef struct st_thr_lock_owner
 
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{
 
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  THR_LOCK_INFO *info;
 
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} THR_LOCK_OWNER;
 
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typedef struct st_thr_lock_data {
 
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  THR_LOCK_OWNER *owner;
 
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  struct st_thr_lock_data *next,**prev;
 
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  struct st_thr_lock *lock;
 
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  pthread_cond_t *cond;
 
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  enum thr_lock_type type;
 
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  void *status_param;                   /* Param to status functions */
 
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  void *debug_print_param;
 
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} THR_LOCK_DATA;
 
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struct st_lock_list {
 
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  THR_LOCK_DATA *data,**last;
 
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};
 
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typedef struct st_thr_lock {
 
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  LIST list;
 
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  pthread_mutex_t mutex;
 
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  struct st_lock_list read_wait;
 
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  struct st_lock_list read;
 
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  struct st_lock_list write_wait;
 
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  struct st_lock_list write;
 
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  /* write_lock_count is incremented for write locks and reset on read locks */
 
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  ulong write_lock_count;
 
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  uint read_no_write_count;
 
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  void (*get_status)(void*, int);       /* When one gets a lock */
 
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  void (*copy_status)(void*,void*);
 
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  void (*update_status)(void*);         /* Before release of write */
 
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  void (*restore_status)(void*);         /* Before release of read */
 
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  my_bool (*check_status)(void *);
 
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} THR_LOCK;
 
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extern LIST *thr_lock_thread_list;
 
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extern pthread_mutex_t THR_LOCK_lock;
 
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my_bool init_thr_lock(void);            /* Must be called once/thread */
 
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#define thr_lock_owner_init(owner, info_arg) (owner)->info= (info_arg)
 
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void thr_lock_info_init(THR_LOCK_INFO *info);
 
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void thr_lock_init(THR_LOCK *lock);
 
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void thr_lock_delete(THR_LOCK *lock);
 
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void thr_lock_data_init(THR_LOCK *lock,THR_LOCK_DATA *data,
 
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                        void *status_param);
 
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enum enum_thr_lock_result thr_lock(THR_LOCK_DATA *data,
 
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                                   THR_LOCK_OWNER *owner,
 
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                                   enum thr_lock_type lock_type);
 
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void thr_unlock(THR_LOCK_DATA *data);
 
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enum enum_thr_lock_result thr_multi_lock(THR_LOCK_DATA **data,
 
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                                         uint count, THR_LOCK_OWNER *owner);
 
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void thr_multi_unlock(THR_LOCK_DATA **data,uint count);
 
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void thr_abort_locks(THR_LOCK *lock, my_bool upgrade_lock);
 
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my_bool thr_abort_locks_for_thread(THR_LOCK *lock, my_thread_id thread);
 
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void thr_print_locks(void);             /* For debugging */
 
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my_bool thr_upgrade_write_delay_lock(THR_LOCK_DATA *data,
 
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                                     enum thr_lock_type new_lock_type);
 
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void    thr_downgrade_write_lock(THR_LOCK_DATA *data,
 
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                                 enum thr_lock_type new_lock_type);
 
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my_bool thr_reschedule_write_lock(THR_LOCK_DATA *data);
 
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#ifdef  __cplusplus
 
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}
 
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#endif
 
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#endif /* _thr_lock_h */