Automerg

4 files changed, 41 insertions, 4 deletions

diff --git a/mysys/Makefile.am b/mysys/Makefile.am
index 8fea7fff4b0..16f0e1a9759 100644
--- a/mysys/Makefile.am
+++ b/mysys/Makefile.am
@@ -1,4 +1,4 @@
-# Copyright (C) 2000-2006 MySQL AB
+# Copyright (C) 2000-2006 MySQL AB, 2009 Sun Microsystems, Inc.
 # 
 # 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
@@ -25,7 +25,7 @@ libmysys_a_SOURCES =    my_init.c my_getwd.c mf_getdate.c my_mmap.c \
 			mf_path.c mf_loadpath.c my_file.c \
 			my_open.c my_create.c my_dup.c my_seek.c my_read.c \
 			my_pread.c my_write.c my_getpagesize.c \
-			mf_keycache.c mf_keycaches.c my_crc32.c \
+			mf_keycaches.c my_crc32.c \
 			mf_iocache.c mf_iocache2.c mf_cache.c mf_tempfile.c \
 			mf_tempdir.c my_lock.c mf_brkhant.c my_alarm.c \
 			my_malloc.c my_realloc.c my_once.c mulalloc.c \
@@ -53,6 +53,14 @@ libmysys_a_SOURCES =    my_init.c my_getwd.c mf_getdate.c my_mmap.c \
 			my_handler.c my_netware.c my_largepage.c \
 			my_memmem.c stacktrace.c \
 			my_windac.c my_access.c base64.c my_libwrap.c
+
+if NEED_THREAD
+# mf_keycache is used only in the server, so it is safe to leave the file
+# out of the non-threaded library.
+# In fact, it will currently not compile without thread support.
+libmysys_a_SOURCES +=   mf_keycache.c
+endif
+
 EXTRA_DIST =		thr_alarm.c thr_lock.c my_pthread.c my_thr_init.c \
 			thr_mutex.c thr_rwlock.c \
 			CMakeLists.txt mf_soundex.c \
diff --git a/mysys/my_static.c b/mysys/my_static.c
index d0c20da828a..a21a3d11104 100644
--- a/mysys/my_static.c
+++ b/mysys/my_static.c
@@ -92,6 +92,14 @@ int (*error_handler_hook)(uint error,const char *str,myf MyFlags)=
 int (*fatal_error_handler_hook)(uint error,const char *str,myf MyFlags)=
   my_message_no_curses;
 
+#if defined(ENABLED_DEBUG_SYNC)
+/**
+  Global pointer to be set if callback function is defined
+  (e.g. in mysqld). See sql/debug_sync.cc.
+*/
+void (*debug_sync_C_callback_ptr)(const char *, size_t);
+#endif /* defined(ENABLED_DEBUG_SYNC) */
+
 #ifdef __WIN__
 /* from my_getsystime.c */
 ulonglong query_performance_frequency, query_performance_offset;
diff --git a/mysys/my_wincond.c b/mysys/my_wincond.c
index d1b07b61408..1134d40229a 100644
--- a/mysys/my_wincond.c
+++ b/mysys/my_wincond.c
@@ -120,13 +120,12 @@ int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
   LeaveCriticalSection(&cond->lock_waiting);
 
   LeaveCriticalSection(mutex);
-
   result= WaitForMultipleObjects(2, cond->events, FALSE, timeout);
   
   EnterCriticalSection(&cond->lock_waiting);
   cond->waiting--;
   
-  if (cond->waiting == 0 && result == (WAIT_OBJECT_0+BROADCAST))
+  if (cond->waiting == 0)
   {
     /*
       We're the last waiter to be notified or to stop waiting, so
diff --git a/mysys/thr_lock.c b/mysys/thr_lock.c
index 31638ecee9a..0e0e93cf220 100644
--- a/mysys/thr_lock.c
+++ b/mysys/thr_lock.c
@@ -398,6 +398,28 @@ wait_for_lock(struct st_lock_list *wait, THR_LOCK_DATA *data,
   my_bool can_deadlock= test(data->owner->info->n_cursors);
   DBUG_ENTER("wait_for_lock");
 
+  /*
+    One can use this to signal when a thread is going to wait for a lock.
+    See debug_sync.cc.
+
+    Beware of waiting for a signal here. The lock has aquired its mutex.
+    While waiting on a signal here, the locking thread could not aquire
+    the mutex to release the lock. One could lock up the table
+    completely.
+
+    In detail it works so: When thr_lock() tries to acquire a table
+    lock, it locks the lock->mutex, checks if it can have the lock, and
+    if not, it calls wait_for_lock(). Here it unlocks the table lock
+    while waiting on a condition. The sync point is located before this
+    wait for condition. If we have a waiting action here, we hold the
+    the table locks mutex all the time. Any attempt to look at the table
+    lock by another thread blocks it immediately on lock->mutex. This
+    can easily become an unexpected and unobvious blockage. So be
+    warned: Do not request a WAIT_FOR action for the 'wait_for_lock'
+    sync point unless you really know what you do.
+  */
+  DEBUG_SYNC_C("wait_for_lock");
+
   if (!in_wait_list)
   {
     (*wait->last)=data;				/* Wait for lock */