Fix for bug 254 :

we now make a distinction between if the master is < 3.23.57, 3.23 && >=57, and 4.x
(before the 2 3.23 were one). This is because in 3.23.57 we have a way to distinguish between
a Start_log_event written at server startup and one written at FLUSH LOGS, so we
have a way to know if the slave must drop old temp tables or not.
Change: mi->old_format was bool, now it's enum (to handle 3 cases). However, functions
which had 'bool old_format' as an argument have their prototypes unchanged, because
the old old_format == 0 now corresponds to the enum value BINLOG_FORMAT_CURRENT which
is equal to 0, so boolean tests are left untouched. The only case were we use mi->old_format
as an enum instead of casting it implicitly to a bool, is in Start_log_event::exec_event,
where we want to distinguish between the 3 possible enum values.


sql/log_event.cc:
  Fix for bug 254 :
  we now make a distinction between if the master is < 3.23.57, 3.23 && >=57, and 4.x
  (before the 2 3.23 were one), to know if the slave must drop old temp tables or not.
sql/slave.cc:
  Fix for bug 254 : mi->old_format is now enum.
  An unrelated comment.
sql/slave.h:
  fix for bug 254 : mi->old_format is now enum.

1 files changed, 27 insertions, 11 deletions

diff --git a/sql/log_event.cc b/sql/log_event.cc
index 369ef940af2..ff968babcf0 100644
--- a/sql/log_event.cc
+++ b/sql/log_event.cc
@@ -2000,11 +2000,8 @@ int Load_log_event::exec_event(NET* net, struct st_relay_log_info* rli,
 
   IMPLEMENTATION
     - To handle the case where the master died without a stop event,
-      we clean up all temporary tables + locks that we got.
-      However, we don't clean temporary tables if the master was 3.23
-      (this is because a 3.23 master writes a Start_log_event at every
-      binlog rotation; if we were not careful we would remove temp tables
-      on the slave when FLUSH LOGS is issued on the master). 
+      we clean up all temporary tables that we got, if we are sure we
+      can (see below).
 
   TODO
     - Remove all active user locks
@@ -2015,18 +2012,37 @@ int Load_log_event::exec_event(NET* net, struct st_relay_log_info* rli,
 
 int Start_log_event::exec_event(struct st_relay_log_info* rli)
 {
-  if (!rli->mi->old_format)
-  {
+
+  switch (rli->mi->old_format) {
+  case BINLOG_FORMAT_CURRENT : 
     /* 
-       If 4.0 master, all temporary tables have been deleted on the master; 
-       if 3.23 master, this is far from sure.
+       This is 4.x, so a Start_log_event is only at master startup,
+       so we are sure the master has restarted and cleared his temp tables.
     */
     close_temporary_tables(thd);
+    cleanup_load_tmpdir();
+    break;
+  /* 
+     Now the older formats; in that case load_tmpdir is cleaned up by the I/O
+     thread.
+  */
+  case BINLOG_FORMAT_323_LESS_57 :
     /*
-      If we have old format, load_tmpdir is cleaned up by the I/O thread
+      Cannot distinguish a Start_log_event generated at master startup and
+      one generated by master FLUSH LOGS, so cannot be sure temp tables
+      have to be dropped. So do nothing.
     */
-    cleanup_load_tmpdir();
+    break;
+ case BINLOG_FORMAT_323_GEQ_57 : 
+    /* Can distinguish, based on the value of 'created' */
+    if (created) /* this was generated at master startup*/
+      close_temporary_tables(thd);
+    break;
+  default :
+    /* this case is impossible */
+    return 1;
   }
+
   return Log_event::exec_event(rli);
 }