misc replication bugfixes including some needed modifications in IO_CACHE

likely() and unlikely() branch prediction compiler hint macros
clean-up of comments


include/my_global.h:
  added likely() and unlikely() macros to help some compilers optimize
  the code for architecture-specific branch prediction policies
include/my_sys.h:
  coverted my_b_append_tell() from macro to a function as it needed to be more
  complex to avoid a potential race condition
mysql-test/mysql-test-run.sh:
  hostname-independent relay log name to have consistent SHOW SLAVE STATUS
  output
mysql-test/r/rpl000014.result:
  result update
mysql-test/r/rpl000015.result:
  result update
mysql-test/r/rpl000016.result:
  result update
mysql-test/r/rpl_log.result:
  result update
mysql-test/t/rpl000017-slave.sh:
  proper cleanup of old logs
mysys/mf_iocache.c:
  cosmetic changes + more debugging asserts
mysys/mf_iocache2.c:
  my_b_append_tell()
  cleanup of comments
sql/log.cc:
  fix potential bug - do not rotate log in the middle of event
sql/slave.cc:
  do not write stop events when the server does not actually stop but just 
  rotates the log
  fixed race between queue_event() and show_slave_status()
  clean-up of comments
sql/slave.h:
  added ignore_stop_event flag to SLAVE_LOG_INFO

2 files changed, 42 insertions, 11 deletions

diff --git a/mysys/mf_iocache.c b/mysys/mf_iocache.c
index 34de5dfd7f3..6095cc23716 100644
--- a/mysys/mf_iocache.c
+++ b/mysys/mf_iocache.c
@@ -542,7 +542,7 @@ read_append_buffer:
 
     DBUG_ASSERT(info->append_read_pos <= info->write_pos);
     /*
-      TODO: figure out if the below assert is needed or correct.
+      TODO: figure out if the assert below is needed or correct.
     */
     DBUG_ASSERT(pos_in_file == info->end_of_file); 
     copy_len=min(Count, len_in_buff);
@@ -889,6 +889,17 @@ int my_block_write(register IO_CACHE *info, const byte *Buffer, uint Count,
 
 	/* Flush write cache */
 
+#ifdef THREAD
+#define LOCK_APPEND_BUFFER if (need_append_buffer_lock) \
+  lock_append_buffer(info);
+#define UNLOCK_APPEND_BUFFER if (need_append_buffer_lock) \
+  unlock_append_buffer(info);
+#else
+#define LOCK_APPEND_BUFFER
+#define UNLOCK_APPEND_BUFFER
+#endif
+
+
 int _flush_io_cache(IO_CACHE *info, int need_append_buffer_lock)
 {
   uint length;
@@ -906,8 +917,8 @@ int _flush_io_cache(IO_CACHE *info, int need_append_buffer_lock)
       if (real_open_cached_file(info))
 	DBUG_RETURN((info->error= -1));
     }
-    if (need_append_buffer_lock)
-      lock_append_buffer(info);
+    LOCK_APPEND_BUFFER;
+    
     if ((length=(uint) (info->write_pos - info->write_buffer)))
     {
       pos_in_file=info->pos_in_file;
@@ -919,8 +930,7 @@ int _flush_io_cache(IO_CACHE *info, int need_append_buffer_lock)
 	if (my_seek(info->file,pos_in_file,MY_SEEK_SET,MYF(0)) ==
 	    MY_FILEPOS_ERROR)
 	{
-	  if (need_append_buffer_lock)
-	    unlock_append_buffer(info);
+	  UNLOCK_APPEND_BUFFER;
 	  DBUG_RETURN((info->error= -1));
 	}
 	if (!append_cache)
@@ -941,11 +951,13 @@ int _flush_io_cache(IO_CACHE *info, int need_append_buffer_lock)
         set_if_bigger(info->end_of_file,(pos_in_file+length));
       }
       else
+      {
 	info->end_of_file+=(info->write_pos-info->append_read_pos);
+	DBUG_ASSERT(info->end_of_file == my_tell(info->file,MYF(0)));
+      }
       
       info->append_read_pos=info->write_pos=info->write_buffer;
-      if (need_append_buffer_lock)
-        unlock_append_buffer(info);
+      UNLOCK_APPEND_BUFFER;
       DBUG_RETURN(info->error);
     }
   }
@@ -956,8 +968,7 @@ int _flush_io_cache(IO_CACHE *info, int need_append_buffer_lock)
     info->inited=0;
   }
 #endif
-  if (need_append_buffer_lock)
-    unlock_append_buffer(info);
+  UNLOCK_APPEND_BUFFER;
   DBUG_RETURN(0);
 }
 
diff --git a/mysys/mf_iocache2.c b/mysys/mf_iocache2.c
index ca9c9938cd2..a343829d32e 100644
--- a/mysys/mf_iocache2.c
+++ b/mysys/mf_iocache2.c
@@ -23,10 +23,30 @@
 #include <m_string.h>
 #include <stdarg.h>
 #include <m_ctype.h>
+#include <assert.h>
+
+my_off_t my_b_append_tell(IO_CACHE* info)
+{
+  my_off_t res; 
+/* we need to lock the append buffer mutex to keep flush_io_cache()
+   from messing with the variables that we need in order to provide the
+   answer to the question.
+*/
+#ifdef THREAD
+  pthread_mutex_lock(&info->append_buffer_lock);
+#endif
+  DBUG_ASSERT(info->end_of_file - (info->append_read_pos-info->write_buffer)
+	      == my_tell(info->file,MYF(0)));
+  res = info->end_of_file + (info->write_pos-info->append_read_pos);
+#ifdef THREAD
+  pthread_mutex_unlock(&info->append_buffer_lock);
+#endif
+  return res;
+}
 
 /*
-  Fix that next read will be made at certain position
-  For write cache, make next write happen at a certain position
+  Make next read happen at the given position
+  For write cache, make next write happen at the given position
 */
 
 void my_b_seek(IO_CACHE *info,my_off_t pos)