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Viewing changes to storage/innobase/lock/lock0iter.c

  • Committer: brian
  • Date: 2008-06-25 05:29:13 UTC
  • Revision ID: brian@localhost.localdomain-20080625052913-6upwo0jsrl4lnapl
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storage/innobase/lock/lock0iter.c
 
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/******************************************************
 
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Lock queue iterator. Can iterate over table and record
 
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lock queues.
 
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(c) 2007 Innobase Oy
 
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Created July 16, 2007 Vasil Dimov
 
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*******************************************************/
 
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#define LOCK_MODULE_IMPLEMENTATION
 
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#include "univ.i"
 
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#include "lock0iter.h"
 
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#include "lock0lock.h"
 
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#include "lock0priv.h"
 
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#include "ut0dbg.h"
 
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#include "ut0lst.h"
 
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/***********************************************************************
 
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Initialize lock queue iterator so that it starts to iterate from
 
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"lock". bit_no specifies the record number within the heap where the
 
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record is stored. It can be undefined (ULINT_UNDEFINED) in two cases:
 
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1. If the lock is a table lock, thus we have a table lock queue;
 
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2. If the lock is a record lock and it is a wait lock. In this case
 
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   bit_no is calculated in this function by using
 
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   lock_rec_find_set_bit(). There is exactly one bit set in the bitmap
 
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   of a wait lock. */
 
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void
 
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lock_queue_iterator_reset(
 
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/*======================*/
 
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        lock_queue_iterator_t*  iter,   /* out: iterator */
 
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        lock_t*                 lock,   /* in: lock to start from */
 
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        ulint                   bit_no) /* in: record number in the
 
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                                        heap */
 
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{
 
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        iter->current_lock = lock;
 
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        if (bit_no != ULINT_UNDEFINED) {
 
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                iter->bit_no = bit_no;
 
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        } else {
 
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                switch (lock_get_type(lock)) {
 
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                case LOCK_TABLE:
 
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                        iter->bit_no = ULINT_UNDEFINED;
 
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                        break;
 
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                case LOCK_REC:
 
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                        iter->bit_no = lock_rec_find_set_bit(lock);
 
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                        ut_a(iter->bit_no != ULINT_UNDEFINED);
 
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                        break;
 
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                default:
 
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                        ut_error;
 
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                }
 
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        }
 
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}
 
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/***********************************************************************
 
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Gets the previous lock in the lock queue, returns NULL if there are no
 
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more locks (i.e. the current lock is the first one). The iterator is
 
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receded (if not-NULL is returned). */
 
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lock_t*
 
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lock_queue_iterator_get_prev(
 
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/*=========================*/
 
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                                        /* out: previous lock or NULL */
 
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        lock_queue_iterator_t*  iter)   /* in/out: iterator */
 
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{
 
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        lock_t* prev_lock;
 
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        switch (lock_get_type(iter->current_lock)) {
 
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        case LOCK_REC:
 
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                prev_lock = lock_rec_get_prev(
 
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                        iter->current_lock, iter->bit_no);
 
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                break;
 
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        case LOCK_TABLE:
 
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                prev_lock = UT_LIST_GET_PREV(
 
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                        un_member.tab_lock.locks, iter->current_lock);
 
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                break;
 
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        default:
 
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                ut_error;
 
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        }
 
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        if (prev_lock != NULL) {
 
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                iter->current_lock = prev_lock;
 
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        }
 
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        return(prev_lock);
 
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}