Bug #51648 DBUG_SYNC_POINT is not defined on all platforms and mtr cant pre-check that

DBUG_SYNC_POINT has at least one strong limitation that it's not defined
on all platforms. It has issues cooperating with @@debug.
All in all its functionality is superseded by DEBUG_SYNC facility and
there is no reason to maintain the old less flexible one.

Fixed with adding debug_sync_set_action() function as a facility to set up
a sync-action in the server sources code and re-writing existing simulations
(found 3) to use it.
Couple of tests have been reworked as well.

The patch offers a pattern for setting sync-points in replication threads
where the standard DEBUG_SYNC does not suffice to reach goals.





mysql-test/extra/rpl_tests/rpl_get_master_version_and_clock.test:
  rewriting the test from GET_LOCK()-based to DEBUG_SYNC-based;
  a pattern of usage DEBUG_SYNC for replication testing is provided.
mysql-test/suite/rpl/r/rpl_get_master_version_and_clock.result:
  results are changed.
mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test:
  rewriting the test from GET_LOCK()-based to DEBUG_SYNC-based;
  limiting the test to run only with MIXED binlog-format as the test last
  some 10 secs sensitively contributing to the total of tests run.
mysql-test/suite/rpl/t/rpl_show_slave_running.test:
  rewriting the test from GET_LOCK()-based to DEBUG_SYNC-based.
sql/debug_sync.cc:
  adding debug_sync_set_action() function as a facility to set up
  a sync-action in the server sources code.
sql/debug_sync.h:
  externalizing debug_sync_set_action().
sql/item_func.cc:
  purging sources from DBUG_SYNC_POINT.
sql/mysql_priv.h:
  purging sources from DBUG_SYNC_POINT.
sql/slave.cc:
  rewriting failure simulations to base on DEBUG_SYNC rather than GET_LOCK()-based DBUG_SYNC_POINT.
sql/sql_repl.cc:
  removing an orphan failure simulation line because no counterpart in tests existing.

1 files changed, 0 insertions, 74 deletions

diff --git a/sql/item_func.cc b/sql/item_func.cc
index 845654c1881..1e31755179b 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -3362,80 +3362,6 @@ longlong Item_master_pos_wait::val_int()
   return event_count;
 }
 
-#ifdef EXTRA_DEBUG
-void debug_sync_point(const char* lock_name, uint lock_timeout)
-{
-  THD* thd=current_thd;
-  User_level_lock* ull;
-  struct timespec abstime;
-  size_t lock_name_len;
-  lock_name_len= strlen(lock_name);
-  pthread_mutex_lock(&LOCK_user_locks);
-
-  if (thd->ull)
-  {
-    item_user_lock_release(thd->ull);
-    thd->ull=0;
-  }
-
-  /*
-    If the lock has not been aquired by some client, we do not want to
-    create an entry for it, since we immediately release the lock. In
-    this case, we will not be waiting, but rather, just waste CPU and
-    memory on the whole deal
-  */
-  if (!(ull= ((User_level_lock*) hash_search(&hash_user_locks,
-                                             (uchar*) lock_name,
-                                             lock_name_len))))
-  {
-    pthread_mutex_unlock(&LOCK_user_locks);
-    return;
-  }
-  ull->count++;
-
-  /*
-    Structure is now initialized.  Try to get the lock.
-    Set up control struct to allow others to abort locks
-  */
-  thd_proc_info(thd, "User lock");
-  thd->mysys_var->current_mutex= &LOCK_user_locks;
-  thd->mysys_var->current_cond=  &ull->cond;
-
-  set_timespec(abstime,lock_timeout);
-  while (ull->locked && !thd->killed)
-  {
-    int error= pthread_cond_timedwait(&ull->cond, &LOCK_user_locks, &abstime);
-    if (error == ETIMEDOUT || error == ETIME)
-      break;
-  }
-
-  if (ull->locked)
-  {
-    if (!--ull->count)
-      delete ull;				// Should never happen
-  }
-  else
-  {
-    ull->locked=1;
-    ull->set_thread(thd);
-    thd->ull=ull;
-  }
-  pthread_mutex_unlock(&LOCK_user_locks);
-  pthread_mutex_lock(&thd->mysys_var->mutex);
-  thd_proc_info(thd, 0);
-  thd->mysys_var->current_mutex= 0;
-  thd->mysys_var->current_cond=  0;
-  pthread_mutex_unlock(&thd->mysys_var->mutex);
-  pthread_mutex_lock(&LOCK_user_locks);
-  if (thd->ull)
-  {
-    item_user_lock_release(thd->ull);
-    thd->ull=0;
-  }
-  pthread_mutex_unlock(&LOCK_user_locks);
-}
-
-#endif
 
 /**
   Get a user level lock.  If the thread has an old lock this is first released.