Backport MySQL WL#2540 into MariaDB.

Patch backported:

bzr diff
'-rrevid:alfranio.correia@oracle.com-20101121143257-se3vpqus73l4mum0
..revid:luis.soares@oracle.com-20101124111752-9b8260bd1qak87hr'
--old=lp:mysql-server --new=lp:mysql-server

1 files changed, 35 insertions, 1 deletions

diff --git a/sql/log.h b/sql/log.h
index 503e94df981..6437046b17b 100644
--- a/sql/log.h
+++ b/sql/log.h
@@ -403,7 +403,41 @@ public:
 
   /* This is relay log */
   bool is_relay_log;
-
+  uint8 checksum_alg_reset; // to contain a new value when binlog is rotated
+  /*
+    Holds the last seen in Relay-Log FD's checksum alg value.
+    The initial value comes from the slave's local FD that heads
+    the very first Relay-Log file. In the following the value may change
+    with each received master's FD_m.
+    Besides to be used in verification events that IO thread receives
+    (except the 1st fake Rotate, see @c Master_info:: checksum_alg_before_fd), 
+    the value specifies if/how to compute checksum for slave's local events
+    and the first fake Rotate (R_f^1) coming from the master.
+    R_f^1 needs logging checksum-compatibly with the RL's heading FD_s.
+
+    Legends for the checksum related comments:
+
+    FD     - Format-Description event,
+    R      - Rotate event
+    R_f    - the fake Rotate event
+    E      - an arbirary event
+
+    The underscore indexes for any event
+    `_s'   indicates the event is generated by Slave
+    `_m'   - by Master
+
+    Two special underscore indexes of FD:
+    FD_q   - Format Description event for queuing   (relay-logging)
+    FD_e   - Format Description event for executing (relay-logging)
+
+    Upper indexes:
+    E^n    - n:th event is a sequence
+
+    RL     - Relay Log
+    (A)    - checksum algorithm descriptor value
+    FD.(A) - the value of (A) in FD
+  */
+  uint8 relay_log_checksum_alg;
   /*
     These describe the log's format. This is used only for relay logs.
     _for_exec is used by the SQL thread, _for_queue by the I/O thread. It's