bzr commit into mysql-5.1-bugteam branch (davi:3051) Bug#43435

[Davi Arnaut]

# At a local mysql-5.1-bugteam repository of davi

 3051 Davi Arnaut	2009-07-30
      Bug#43435: LOCK_open does not use MY_MUTEX_INIT_FAST
      
      Initialize LOCK_open as a adapative mutex on platforms where the
      PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP macro is available. The flag
      indicates that a thread should spin (busy wait) for some time on a
      locked adaptive mutex before blocking (sleeping). It's intended to
      to alleviate performance problems due to LOCK_open being a highly
      contended mutex.
     @ sql/mysqld.cc
        Initialize LOCK_open as a adapative mutex.

    modified:
      sql/mysqld.cc
=== modified file 'sql/mysqld.cc'
--- a/sql/mysqld.cc	2009-07-30 19:11:39 +0000
+++ b/sql/mysqld.cc	2009-07-30 20:52:42 +0000
@@ -3519,7 +3519,7 @@ static int init_thread_environment()
   (void) pthread_mutex_init(&LOCK_mysql_create_db,MY_MUTEX_INIT_SLOW);
   (void) pthread_mutex_init(&LOCK_lock_db,MY_MUTEX_INIT_SLOW);
   (void) pthread_mutex_init(&LOCK_Acl,MY_MUTEX_INIT_SLOW);
-  (void) pthread_mutex_init(&LOCK_open, NULL);
+  (void) pthread_mutex_init(&LOCK_open, MY_MUTEX_INIT_FAST);
   (void) pthread_mutex_init(&LOCK_thread_count,MY_MUTEX_INIT_FAST);
   (void) pthread_mutex_init(&LOCK_mapped_file,MY_MUTEX_INIT_SLOW);
   (void) pthread_mutex_init(&LOCK_status,MY_MUTEX_INIT_FAST);


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