This is a fix for a bug in 3.23 -> 4.0 replication: Exec_master_log_pos is always

too big by 6 bytes. So I add code to substract 6 bytes if the master is 3.23.
This is not perfect (because it won't work if the slave I/O thread has not
noticed yet that the master is 3.23), but as long as the slave I/O thread
starts Exec_master_log_pos will be ok.
It must be merged to 4.1 but not to 5.0 (or it can be, because of #if MYSQL_VERSION_ID),
because 5.0 already works if the master is 3.23 (and in a more natural way:
in 5.0 we store the end_log_pos in the binlog and relay log).
I had to move functions from slave.h to slave.cc to satisfy gcc.


sql/log_event.cc:
  make the event's length 6 bytes shorter if the master is 3.23
sql/slave.cc:
  Moving several st_relay_log_info methods out of the declaration of the struct,
  because gcc complained that 'mi' was not declared.
  Substracting 6 bytes from the event's length in inc_pos() if the master is 3.23.
sql/slave.h:
  moving several methods out of the declaration of st_relay_log_info.
  Removing 'inline', let's have the compiler decide.

1 files changed, 46 insertions, 0 deletions

diff --git a/sql/slave.cc b/sql/slave.cc
index d6dda473be0..9e82a521cb3 100644
--- a/sql/slave.cc
+++ b/sql/slave.cc
@@ -329,6 +329,52 @@ void init_slave_skip_errors(const char* arg)
   }
 }
 
+void st_relay_log_info::inc_pending(ulonglong val)
+{
+  pending += val;
+}
+
+/* TODO: this probably needs to be fixed */
+void st_relay_log_info::inc_pos(ulonglong val, ulonglong log_pos, bool skip_lock)
+{
+  if (!skip_lock)
+    pthread_mutex_lock(&data_lock);
+  relay_log_pos += val+pending;
+  pending = 0;
+  if (log_pos)
+#if MYSQL_VERSION_ID < 50000
+    /*
+      If the event was converted from a 3.23 format, get_event_len() has
+      grown by 6 bytes (at least for most events, except LOAD DATA INFILE
+      which is already a big problem for 3.23->4.0 replication); 6 bytes is
+      the difference between the header's size in 4.0 (LOG_EVENT_HEADER_LEN)
+      and the header's size in 3.23 (OLD_HEADER_LEN). Note that using
+      mi->old_format will not help if the I/O thread has not started yet.
+      Yes this is a hack but it's just to make 3.23->4.x replication work;
+      3.23->5.0 replication is working much better.
+      
+      The line "mi->old_format ? : " below should NOT BE MERGED to 5.0 which
+      already works. But it SHOULD be merged to 4.1.
+    */
+    master_log_pos= log_pos + val -
+      (mi->old_format ? (LOG_EVENT_HEADER_LEN - OLD_HEADER_LEN) : 0);
+#endif
+  pthread_cond_broadcast(&data_cond);
+  if (!skip_lock)
+    pthread_mutex_unlock(&data_lock);
+}
+
+/*
+  thread safe read of position - not needed if we are in the slave thread,
+  but required otherwise as var is a longlong
+*/
+void st_relay_log_info::read_pos(ulonglong& var)
+{
+  pthread_mutex_lock(&data_lock);
+  var = relay_log_pos;
+  pthread_mutex_unlock(&data_lock);
+}
+
 void st_relay_log_info::close_temporary_tables()
 {
   TABLE *table,*next;