More DBUG statements

Replaced COND_refresh with COND_global_read_lock becasue of a bug in NTPL threads when using different mutexes as arguments to pthread_cond_wait()
The original code caused a hang in FLUSH TABLES WITH READ LOCK in some circumstances because pthread_cond_broadcast() was not delivered to other threads.
This fixes:
Bug#16986: Deadlock condition with MyISAM tables
Bug#20048: FLUSH TABLES WITH READ LOCK causes a deadlock

1 files changed, 4 insertions, 4 deletions

diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 50f19c15fc4..2dcef245a99 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -516,7 +516,7 @@ pthread_mutex_t LOCK_prepared_stmt_count;
 pthread_mutex_t LOCK_des_key_file;
 #endif
 rw_lock_t	LOCK_grant, LOCK_sys_init_connect, LOCK_sys_init_slave;
-pthread_cond_t COND_refresh,COND_thread_count;
+pthread_cond_t COND_refresh,COND_thread_count, COND_global_read_lock;
 pthread_t signal_thread;
 pthread_attr_t connection_attrib;
 
@@ -1235,6 +1235,7 @@ static void clean_up_mutexes()
   (void) pthread_mutex_destroy(&LOCK_prepared_stmt_count);
   (void) pthread_cond_destroy(&COND_thread_count);
   (void) pthread_cond_destroy(&COND_refresh);
+  (void) pthread_cond_destroy(&COND_global_read_lock);
   (void) pthread_cond_destroy(&COND_thread_cache);
   (void) pthread_cond_destroy(&COND_flush_thread_cache);
   (void) pthread_cond_destroy(&COND_manager);
@@ -1657,13 +1658,11 @@ void end_thread(THD *thd, bool put_in_cache)
     }
   }
 
-  DBUG_PRINT("info", ("sending a broadcast"))
-
   /* Tell main we are ready */
   (void) pthread_mutex_unlock(&LOCK_thread_count);
   /* It's safe to broadcast outside a lock (COND... is not deleted here) */
+  DBUG_PRINT("signal", ("Broadcasting COND_thread_count"));
   (void) pthread_cond_broadcast(&COND_thread_count);
-  DBUG_PRINT("info", ("unlocked thread_count mutex"))
 #ifdef ONE_THREAD
   if (!(test_flags & TEST_NO_THREADS))	// For debugging under Linux
 #endif
@@ -2811,6 +2810,7 @@ static int init_thread_environment()
   (void) my_rwlock_init(&LOCK_grant, NULL);
   (void) pthread_cond_init(&COND_thread_count,NULL);
   (void) pthread_cond_init(&COND_refresh,NULL);
+  (void) pthread_cond_init(&COND_global_read_lock,NULL);
   (void) pthread_cond_init(&COND_thread_cache,NULL);
   (void) pthread_cond_init(&COND_flush_thread_cache,NULL);
   (void) pthread_cond_init(&COND_manager,NULL);