summaryrefslogtreecommitdiff
path: root/sql/event_queue.cc
blob: 516bdc9158fc66d66bde0a21ba886a729b295a08 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
/* Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */

#include "mariadb.h"
#include "sql_priv.h"
#include "unireg.h"
#include "event_queue.h"
#include "event_data_objects.h"
#include "event_db_repository.h"
#include "events.h"
#include "sql_audit.h"
#include "tztime.h"     // my_tz_find, my_tz_OFFSET0, struct Time_zone
#include "log.h"        // sql_print_error
#include "sql_class.h"  // struct THD

/**
  @addtogroup Event_Scheduler
  @{
*/

#define EVENT_QUEUE_INITIAL_SIZE 30
#define EVENT_QUEUE_EXTENT       30

#ifdef __GNUC__
#if __GNUC__ >= 2
#define SCHED_FUNC __FUNCTION__
#endif
#else
#define SCHED_FUNC "<unknown>"
#endif

#define LOCK_QUEUE_DATA()   lock_data(SCHED_FUNC, __LINE__)
#define UNLOCK_QUEUE_DATA() unlock_data(SCHED_FUNC, __LINE__)

/*
  Compares the execute_at members of two Event_queue_element instances.
  Used as callback for the prioritized queue when shifting
  elements inside.

  SYNOPSIS
    event_queue_element_data_compare_q()
      vptr  Not used (set it to NULL)
      a     First Event_queue_element object
      b     Second Event_queue_element object

  RETURN VALUE
   -1   a->execute_at < b->execute_at
    0   a->execute_at == b->execute_at
    1   a->execute_at > b->execute_at

  NOTES
    execute_at.second_part is not considered during comparison
*/

extern "C" int event_queue_element_compare_q(void *, uchar *, uchar *);

int event_queue_element_compare_q(void *vptr, uchar* a, uchar *b)
{
  Event_queue_element *left = (Event_queue_element *)a;
  Event_queue_element *right = (Event_queue_element *)b;
  my_time_t lhs = left->execute_at;
  my_time_t rhs = right->execute_at;

  if (left->status == Event_parse_data::DISABLED)
    return right->status != Event_parse_data::DISABLED;

  if (right->status == Event_parse_data::DISABLED)
    return 1;

  return (lhs < rhs ? -1 : (lhs > rhs ? 1 : 0));
}


/*
  Constructor of class Event_queue.

  SYNOPSIS
    Event_queue::Event_queue()
*/

Event_queue::Event_queue()
  :next_activation_at(0),
   mutex_last_locked_at_line(0),
   mutex_last_unlocked_at_line(0),
   mutex_last_attempted_lock_at_line(0),
   mutex_last_locked_in_func("n/a"),
   mutex_last_unlocked_in_func("n/a"),
   mutex_last_attempted_lock_in_func("n/a"),
   mutex_queue_data_locked(FALSE),
   mutex_queue_data_attempting_lock(FALSE),
   waiting_on_cond(FALSE)
{
  mysql_mutex_init(key_LOCK_event_queue, &LOCK_event_queue, MY_MUTEX_INIT_FAST);
  mysql_cond_init(key_COND_queue_state, &COND_queue_state, NULL);
}


Event_queue::~Event_queue()
{
  deinit_queue();
  mysql_mutex_destroy(&LOCK_event_queue);
  mysql_cond_destroy(&COND_queue_state);
}


/*
  This is a queue's constructor. Until this method is called, the
  queue is unusable.  We don't use a C++ constructor instead in
  order to be able to check the return value. The queue is
  initialized once at server startup.  Initialization can fail in
  case of a failure reading events from the database or out of
  memory.

  SYNOPSIS
    Event_queue::init()

  RETURN VALUE
    FALSE  OK
    TRUE   Error
*/

bool
Event_queue::init_queue(THD *thd)
{
  DBUG_ENTER("Event_queue::init_queue");
  DBUG_PRINT("enter", ("this: %p", this));

  LOCK_QUEUE_DATA();

  if (::init_queue(&queue, EVENT_QUEUE_INITIAL_SIZE , 0 /*offset*/,
                   0 /*max_on_top*/, event_queue_element_compare_q,
                   NullS, 0, EVENT_QUEUE_EXTENT))
  {
    sql_print_error("Event Scheduler: Can't initialize the execution queue");
    goto err;
  }

  UNLOCK_QUEUE_DATA();
  DBUG_RETURN(FALSE);

err:
  UNLOCK_QUEUE_DATA();
  DBUG_RETURN(TRUE);
}


/*
  Deinits the queue. Remove all elements from it and destroys them
  too.

  SYNOPSIS
    Event_queue::deinit_queue()
*/

void
Event_queue::deinit_queue()
{
  DBUG_ENTER("Event_queue::deinit_queue");

  LOCK_QUEUE_DATA();
  empty_queue();
  delete_queue(&queue);
  UNLOCK_QUEUE_DATA();

  DBUG_VOID_RETURN;
}


/**
  Adds an event to the queue.

  Compute the next execution time for an event, and if it is still
  active, add it to the queue. Otherwise delete it.
  The object is left intact in case of an error. Otherwise
  the queue container assumes ownership of it.

  @param[in]  thd      thread handle
  @param[in]  new_element a new element to add to the queue
  @param[out] created  set to TRUE if no error and the element is
                       added to the queue, FALSE otherwise

  @retval TRUE  an error occurred. The value of created is undefined,
                the element was not deleted.
  @retval FALSE success
*/

bool
Event_queue::create_event(THD *thd, Event_queue_element *new_element,
                          bool *created)
{
  DBUG_ENTER("Event_queue::create_event");
  DBUG_PRINT("enter", ("thd: %p et=%s.%s", thd,
             new_element->dbname.str, new_element->name.str));

  /* Will do nothing if the event is disabled */
  new_element->compute_next_execution_time();
  if (new_element->status != Event_parse_data::ENABLED)
  {
    delete new_element;
    *created= FALSE;
    DBUG_RETURN(FALSE);
  }

  DBUG_PRINT("info", ("new event in the queue: %p", new_element));

  LOCK_QUEUE_DATA();
  *created= (queue_insert_safe(&queue, (uchar *) new_element) == FALSE);
  dbug_dump_queue(thd->query_start());
  mysql_cond_broadcast(&COND_queue_state);
  UNLOCK_QUEUE_DATA();

  DBUG_RETURN(!*created);
}


/*
  Updates an event from the scheduler queue

  SYNOPSIS
    Event_queue::update_event()
      thd        Thread
      dbname     Schema of the event
      name       Name of the event
      new_schema New schema, in case of RENAME TO, otherwise NULL
      new_name   New name, in case of RENAME TO, otherwise NULL
*/

void
Event_queue::update_event(THD *thd, const LEX_CSTRING *dbname,
                          const LEX_CSTRING *name,
                          Event_queue_element *new_element)
{
  DBUG_ENTER("Event_queue::update_event");
  DBUG_PRINT("enter", ("thd: %p  et: [%s.%s]", thd, dbname->str,
                       name->str));

  if ((new_element->status == Event_parse_data::DISABLED) ||
      (new_element->status == Event_parse_data::SLAVESIDE_DISABLED))
  {
    DBUG_PRINT("info", ("The event is disabled."));
    /*
      Destroy the object but don't skip to end: because we may have to remove
      object from the cache.
    */
    delete new_element;
    new_element= NULL;
  }
  else
    new_element->compute_next_execution_time();

  LOCK_QUEUE_DATA();
  find_n_remove_event(dbname, name);

  /* If not disabled event */
  if (new_element)
  {
    DBUG_PRINT("info", ("new event in the queue: %p", new_element));
    queue_insert_safe(&queue, (uchar *) new_element);
    mysql_cond_broadcast(&COND_queue_state);
  }

  dbug_dump_queue(thd->query_start());
  UNLOCK_QUEUE_DATA();

  DBUG_VOID_RETURN;
}


/*
  Drops an event from the queue

  SYNOPSIS
    Event_queue::drop_event()
      thd     Thread
      dbname  Schema of the event to drop
      name    Name of the event to drop
*/

void
Event_queue::drop_event(THD *thd, const LEX_CSTRING *dbname,
                        const LEX_CSTRING *name)
{
  DBUG_ENTER("Event_queue::drop_event");
  DBUG_PRINT("enter", ("thd: %p  db: %s  name: %s", thd,
                       dbname->str, name->str));

  LOCK_QUEUE_DATA();
  find_n_remove_event(dbname, name);
  dbug_dump_queue(thd->query_start());
  UNLOCK_QUEUE_DATA();

  /*
    We don't signal here because the scheduler will catch the change
    next time it wakes up.
  */

  DBUG_VOID_RETURN;
}


/*
  Drops all events from the in-memory queue and disk that match
  certain pattern evaluated by a comparator function

  SYNOPSIS
    Event_queue::drop_matching_events()
      thd            THD
      pattern        A pattern string
      comparator     The function to use for comparing

  RETURN VALUE
    >=0  Number of dropped events

  NOTE
    Expected is the caller to acquire lock on LOCK_event_queue
*/

void
Event_queue::drop_matching_events(THD *thd, const LEX_CSTRING *pattern,
                           bool (*comparator)(const LEX_CSTRING *, Event_basic *))
{
  uint i;
  DBUG_ENTER("Event_queue::drop_matching_events");
  DBUG_PRINT("enter", ("pattern: %s", pattern->str));

  for (i= queue_first_element(&queue) ;
       i <= queue_last_element(&queue) ;
       )
  {
    Event_queue_element *et= (Event_queue_element *) queue_element(&queue, i);
    DBUG_PRINT("info", ("[%s.%s]?", et->dbname.str, et->name.str));
    if (comparator(pattern, et))
    {
      /*
        The queue is ordered. If we remove an element, then all elements
        after it will shift one position to the left, if we imagine it as
        an array from left to the right. In this case we should not
        increment the counter and the (i <= queue_last_element() condition
        is ok.
      */
      queue_remove(&queue, i);
      delete et;
    }
    else
      i++;
  }
  /*
    We don't call mysql_cond_broadcast(&COND_queue_state);
    If we remove the top event:
    1. The queue is empty. The scheduler will wake up at some time and
       realize that the queue is empty. If create_event() comes in between
       it will signal the scheduler
    2. The queue is not empty, but the next event after the previous top,
       won't be executed any time sooner than the element we removed. Hence,
       we may not notify the scheduler and it will realize the change when it
       wakes up from timedwait.
  */

  DBUG_VOID_RETURN;
}


/*
  Drops all events from the in-memory queue and disk that are from
  certain schema.

  SYNOPSIS
    Event_queue::drop_schema_events()
      thd        HD
      schema    The schema name
*/

void
Event_queue::drop_schema_events(THD *thd, const LEX_CSTRING *schema)
{
  DBUG_ENTER("Event_queue::drop_schema_events");
  LOCK_QUEUE_DATA();
  drop_matching_events(thd, schema, event_basic_db_equal);
  UNLOCK_QUEUE_DATA();
  DBUG_VOID_RETURN;
}


/*
  Searches for an event in the queue

  SYNOPSIS
    Event_queue::find_n_remove_event()
      db    The schema of the event to find
      name  The event to find

  NOTE
    The caller should do the locking also the caller is responsible for
    actual signalling in case an event is removed from the queue.
*/

void
Event_queue::find_n_remove_event(const LEX_CSTRING *db,
                                 const LEX_CSTRING *name)
{
  uint i;
  DBUG_ENTER("Event_queue::find_n_remove_event");

  for (i= queue_first_element(&queue);
       i <= queue_last_element(&queue);
       i++)
  {
    Event_queue_element *et= (Event_queue_element *) queue_element(&queue, i);
    DBUG_PRINT("info", ("[%s.%s]==[%s.%s]?", db->str, name->str,
                        et->dbname.str, et->name.str));
    if (event_basic_identifier_equal(db, name, et))
    {
      queue_remove(&queue, i);
      delete et;
      break;
    }
  }

  DBUG_VOID_RETURN;
}


/*
  Recalculates activation times in the queue. There is one reason for
  that. Because the values (execute_at) by which the queue is ordered are
  changed by calls to compute_next_execution_time() on a request from the
  scheduler thread, if it is not running then the values won't be updated.
  Once the scheduler is started again the values has to be recalculated
  so they are right for the current time.

  SYNOPSIS
    Event_queue::recalculate_activation_times()
      thd  Thread
*/

void
Event_queue::recalculate_activation_times(THD *thd)
{
  uint i;
  DBUG_ENTER("Event_queue::recalculate_activation_times");

  LOCK_QUEUE_DATA();
  DBUG_PRINT("info", ("%u loaded events to be recalculated", queue.elements));
  for (i= queue_first_element(&queue);
       i <= queue_last_element(&queue);
       i++)
  {
    ((Event_queue_element*)queue_element(&queue, i))->compute_next_execution_time();
  }
  queue_fix(&queue);
  /*
    The disabled elements are moved to the end during the `fix`.
    Start from the end and remove all of the elements which are
    disabled. When we find the first non-disabled one we break, as we
    have removed all. The queue has been ordered in a way the disabled
    events are at the end.
  */
  for (i= queue_last_element(&queue);
       (int) i >= (int) queue_first_element(&queue);
       i--)
  {
    Event_queue_element *element=
      (Event_queue_element*)queue_element(&queue, i);
    if (element->status != Event_parse_data::DISABLED)
      break;
    /*
      This won't cause queue re-order, because we remove
      always the last element.
    */
    queue_remove(&queue, i);
    delete element;
  }
  UNLOCK_QUEUE_DATA();

  /*
    XXX: The events are dropped only from memory and not from disk
         even if `drop_list[j]->dropped` is TRUE. There will be still on the
         disk till next server restart.
         Please add code here to do it.
  */

  DBUG_VOID_RETURN;
}


/*
  Empties the queue and destroys the Event_queue_element objects in the
  queue.

  SYNOPSIS
    Event_queue::empty_queue()

  NOTE
    Should be called with LOCK_event_queue locked
*/

void
Event_queue::empty_queue()
{
  uint i;
  DBUG_ENTER("Event_queue::empty_queue");
  DBUG_PRINT("enter", ("Purging the queue. %u element(s)", queue.elements));
  sql_print_information("Event Scheduler: Purging the queue. %u events",
                        queue.elements);
  /* empty the queue */
  for (i= queue_first_element(&queue);
       i <= queue_last_element(&queue);
       i++)
  {
    Event_queue_element *et= (Event_queue_element *) queue_element(&queue, i);
    delete et;
  }
  resize_queue(&queue, 0);
  DBUG_VOID_RETURN;
}


/*
  Dumps the queue to the trace log.

  SYNOPSIS
    Event_queue::dbug_dump_queue()
      now  Current timestamp
*/

void
Event_queue::dbug_dump_queue(my_time_t when)
{
#ifdef DBUG_TRACE
  my_time_t now= when;
  Event_queue_element *et;
  uint i;
  DBUG_ENTER("Event_queue::dbug_dump_queue");
  DBUG_PRINT("info", ("Dumping queue . Elements=%u", queue.elements));
  for (i= queue_first_element(&queue);
       i <= queue_last_element(&queue);
       i++)
  {
    et= ((Event_queue_element*)queue_element(&queue, i));
    DBUG_PRINT("info", ("et: %p  name: %s.%s", et,
                        et->dbname.str, et->name.str));
    DBUG_PRINT("info", ("exec_at: %lu  starts: %lu  ends: %lu  execs_so_far: %u  "
                        "expr: %ld  et.exec_at: %ld  now: %ld  "
                        "(et.exec_at - now): %d  if: %d",
                        (long) et->execute_at, (long) et->starts,
                        (long) et->ends, et->execution_count,
                        (long) et->expression, (long) et->execute_at,
                        (long) now, (int) (et->execute_at - now),
                        et->execute_at <= now));
  }
  DBUG_VOID_RETURN;
#endif
}

/*
  Checks whether the top of the queue is elligible for execution and
  returns an Event_job_data instance in case it should be executed.
  `now` is compared against `execute_at` of the top element in the queue.

  SYNOPSIS
    Event_queue::get_top_for_execution_if_time()
      thd        [in]  Thread
      event_name [out] The object to execute

  RETURN VALUE
    FALSE  No error. event_name != NULL
    TRUE   Serious error
*/

bool
Event_queue::get_top_for_execution_if_time(THD *thd,
                Event_queue_element_for_exec **event_name)
{
  bool ret= FALSE;
  *event_name= NULL;
  my_time_t UNINIT_VAR(last_executed);
  int UNINIT_VAR(status);
  DBUG_ENTER("Event_queue::get_top_for_execution_if_time");

  LOCK_QUEUE_DATA();
  for (;;)
  {
    Event_queue_element *top= NULL;

    /* Break loop if thd has been killed */
    if (thd->killed)
    {
      DBUG_PRINT("info", ("thd->killed=%d", thd->killed));
      goto end;
    }

    if (!queue.elements)
    {
      /* There are no events in the queue */
      next_activation_at= 0;

      /* Release any held audit resources before waiting */
      mysql_audit_release(thd);

      /* Wait on condition until signaled. Release LOCK_queue while waiting. */
      cond_wait(thd, NULL, & stage_waiting_on_empty_queue, SCHED_FUNC, __FILE__, __LINE__);

      continue;
    }

    top= (Event_queue_element*) queue_top(&queue);

    thd->set_start_time(); /* Get current time */

    next_activation_at= top->execute_at;
    if (next_activation_at > thd->query_start())
    {
      /*
        Not yet time for top event, wait on condition with
        time or until signaled. Release LOCK_queue while waiting.
      */
      struct timespec top_time= { next_activation_at, 0 };

      /* Release any held audit resources before waiting */
      mysql_audit_release(thd);

      cond_wait(thd, &top_time, &stage_waiting_for_next_activation, SCHED_FUNC, __FILE__, __LINE__);

      continue;
    }

    if (!(*event_name= new Event_queue_element_for_exec()) ||
        (*event_name)->init(&top->dbname, &top->name))
    {
      delete *event_name;
      ret= TRUE;
      break;
    }

    DBUG_PRINT("info", ("Ready for execution"));
    top->mark_last_executed(thd);
    if (top->compute_next_execution_time())
      top->status= Event_parse_data::DISABLED;
    DBUG_PRINT("info", ("event %s status is %d", top->name.str, top->status));

    top->execution_count++;
    (*event_name)->dropped= top->dropped;
    /*
      Save new values of last_executed timestamp and event status on stack
      in order to be able to update event description in system table once
      QUEUE_DATA lock is released.
    */
    last_executed= top->last_executed;
    status= top->status;

    if (top->status == Event_parse_data::DISABLED)
    {
      DBUG_PRINT("info", ("removing from the queue"));
      sql_print_information("Event Scheduler: Last execution of %s.%s. %s",
                            top->dbname.str, top->name.str,
                            top->dropped? "Dropping.":"");
      delete top;
      queue_remove_top(&queue);
    }
    else
      queue_replace_top(&queue);

    dbug_dump_queue(thd->query_start());
    break;
  }
end:
  UNLOCK_QUEUE_DATA();

  DBUG_PRINT("info", ("returning %d  et_new: %p ",
                      ret, *event_name));

  if (*event_name)
  {
    DBUG_PRINT("info", ("db: %s  name: %s",
                        (*event_name)->dbname.str, (*event_name)->name.str));

    Event_db_repository *db_repository= Events::get_db_repository();
    (void) db_repository->update_timing_fields_for_event(thd,
                            &(*event_name)->dbname, &(*event_name)->name,
                            last_executed, (ulonglong) status);
  }

  DBUG_RETURN(ret);
}


/*
  Auxiliary function for locking LOCK_event_queue. Used by the
  LOCK_QUEUE_DATA macro

  SYNOPSIS
    Event_queue::lock_data()
      func  Which function is requesting mutex lock
      line  On which line mutex lock is requested
*/

void
Event_queue::lock_data(const char *func, uint line)
{
  DBUG_ENTER("Event_queue::lock_data");
  DBUG_PRINT("enter", ("func=%s line=%u", func, line));
  mutex_last_attempted_lock_in_func= func;
  mutex_last_attempted_lock_at_line= line;
  mutex_queue_data_attempting_lock= TRUE;
  mysql_mutex_lock(&LOCK_event_queue);
  mutex_last_attempted_lock_in_func= "";
  mutex_last_attempted_lock_at_line= 0;
  mutex_queue_data_attempting_lock= FALSE;

  mutex_last_locked_in_func= func;
  mutex_last_locked_at_line= line;
  mutex_queue_data_locked= TRUE;

  DBUG_VOID_RETURN;
}


/*
  Auxiliary function for unlocking LOCK_event_queue. Used by the
  UNLOCK_QUEUE_DATA macro

  SYNOPSIS
    Event_queue::unlock_data()
      func  Which function is requesting mutex unlock
      line  On which line mutex unlock is requested
*/

void
Event_queue::unlock_data(const char *func, uint line)
{
  DBUG_ENTER("Event_queue::unlock_data");
  DBUG_PRINT("enter", ("func=%s line=%u", func, line));
  mutex_last_unlocked_at_line= line;
  mutex_queue_data_locked= FALSE;
  mutex_last_unlocked_in_func= func;
  mysql_mutex_unlock(&LOCK_event_queue);
  DBUG_VOID_RETURN;
}


/*
  Wrapper for mysql_cond_wait/timedwait

  SYNOPSIS
    Event_queue::cond_wait()
      thd     Thread (Could be NULL during shutdown procedure)
      msg     Message for thd->proc_info
      abstime If not null then call mysql_cond_timedwait()
      func    Which function is requesting cond_wait
      line    On which line cond_wait is requested
*/

void
Event_queue::cond_wait(THD *thd, struct timespec *abstime, const PSI_stage_info *stage,
                       const char *src_func, const char *src_file, uint src_line)
{
  DBUG_ENTER("Event_queue::cond_wait");
  waiting_on_cond= TRUE;
  mutex_last_unlocked_at_line= src_line;
  mutex_queue_data_locked= FALSE;
  mutex_last_unlocked_in_func= src_func;

  thd->enter_cond(&COND_queue_state, &LOCK_event_queue, stage, NULL, src_func, src_file, src_line);

  if (!thd->killed)
  {
    DBUG_PRINT("info", ("pthread_cond_%swait", abstime ? "timed" : ""));
    if (!abstime)
      mysql_cond_wait(&COND_queue_state, &LOCK_event_queue);
    else
      mysql_cond_timedwait(&COND_queue_state, &LOCK_event_queue, abstime);
  }

  mutex_last_locked_in_func= src_func;
  mutex_last_locked_at_line= src_line;
  mutex_queue_data_locked= TRUE;
  waiting_on_cond= FALSE;

  /*
    This will free the lock so we need to relock. Not the best thing to
    do but we need to obey cond_wait()
  */
  thd->exit_cond(NULL, src_func, src_file, src_line);
  lock_data(src_func, src_line);

  DBUG_VOID_RETURN;
}


/*
  Dumps the internal status of the queue

  SYNOPSIS
    Event_queue::dump_internal_status()
*/

void
Event_queue::dump_internal_status()
{
  DBUG_ENTER("Event_queue::dump_internal_status");

  /* element count */
  puts("");
  puts("Event queue status:");
  printf("Element count   : %u\n", queue.elements);
  printf("Data locked     : %s\n", mutex_queue_data_locked? "YES":"NO");
  printf("Attempting lock : %s\n", mutex_queue_data_attempting_lock? "YES":"NO");
  printf("LLA             : %s:%u\n", mutex_last_locked_in_func,
                                        mutex_last_locked_at_line);
  printf("LUA             : %s:%u\n", mutex_last_unlocked_in_func,
                                        mutex_last_unlocked_at_line);
  if (mutex_last_attempted_lock_at_line)
    printf("Last lock attempt at: %s:%u\n", mutex_last_attempted_lock_in_func,
                                            mutex_last_attempted_lock_at_line);
  printf("WOC             : %s\n", waiting_on_cond? "YES":"NO");

  MYSQL_TIME time;
  my_tz_OFFSET0->gmt_sec_to_TIME(&time, next_activation_at);
  if (time.year != 1970)
    printf("Next activation : %04d-%02d-%02d %02d:%02d:%02d\n",
           time.year, time.month, time.day, time.hour, time.minute, time.second);
  else
    printf("Next activation : never");

  DBUG_VOID_RETURN;
}

/**
  @} (End of group Event_Scheduler)
*/