mysqltest: Write command to be executed to the log BEFORE executing the command.

Fixed race condition in event that could cause hang when stopping event scheduler with SET GLOBAL event_scheduler=OFF 

client/mysqltest.cc:
  Write command to be executed to the log BEFORE executing the command.
  This makes it easier to debug crashes as the log will contain the fatal command.
mysql-test/r/mysqltest.result:
  Updated results (we now get more things logged)
sql/event_queue.cc:
  Fixed race condition in event that could cause hang when stopping event scheduler with SET GLOBAL event_scheduler=OFF.
  The reason was that a kill signal could be sent between last check of thd->killed and before thd->enter_cond() in which case the signal
  would be missed and we would be stuck in Event_scheduler::stop() forever.

1 files changed, 8 insertions, 6 deletions

diff --git a/sql/event_queue.cc b/sql/event_queue.cc
index d68dc8ef479..b9585dc9c51 100644
--- a/sql/event_queue.cc
+++ b/sql/event_queue.cc
@@ -734,12 +734,14 @@ Event_queue::cond_wait(THD *thd, struct timespec *abstime, const char* msg,
 
   thd->enter_cond(&COND_queue_state, &LOCK_event_queue, msg);
 
-  DBUG_PRINT("info", ("pthread_cond_%swait", abstime? "timed":""));
-  if (!abstime)
-    pthread_cond_wait(&COND_queue_state, &LOCK_event_queue);
-  else
-    pthread_cond_timedwait(&COND_queue_state, &LOCK_event_queue, abstime);
-
+  if (!thd->killed)
+  {
+    DBUG_PRINT("info", ("pthread_cond_%swait", abstime ? "timed" : ""));
+    if (!abstime)
+      pthread_cond_wait(&COND_queue_state, &LOCK_event_queue);
+    else
+      pthread_cond_timedwait(&COND_queue_state, &LOCK_event_queue, abstime);
+  }
   mutex_last_locked_in_func= func;
   mutex_last_locked_at_line= line;
   mutex_queue_data_locked= TRUE;