MDEV-7194: galera fails to replicate DDL queries when using binlog_checksum

Restore fix for MDEV-4328 (revno: 3391) that got accidentally
overwritten while merging :
http://bazaar.launchpad.net/~codership/codership-mysql/5.5-23/revision/3900

Added a test case.

mysql-test/suite/galera/r/binlog_checksum.result

+# On node_1
+SET @binlog_checksum_saved= @@GLOBAL.BINLOG_CHECKSUM;
+SET @@GLOBAL.BINLOG_CHECKSUM=CRC32;
+# On node_2
+SET @binlog_checksum_saved= @@GLOBAL.BINLOG_CHECKSUM;
+SET @@GLOBAL.BINLOG_CHECKSUM=CRC32;
+USE test;
+CREATE TABLE t1(c1 INT PRIMARY KEY) ENGINE=INNODB;
+INSERT INTO t1 VALUES (1), (2), (3), (4), (5);
+SELECT * FROM t1;
+c1
+1
+2
+3
+4
+5
+SELECT * FROM test.t1;
+c1
+1
+2
+3
+4
+5
+
+# On node_2
+SELECT * FROM test.t1;
+c1
+1
+2
+3
+4
+5
+DROP TABLE t1;
+SET @@GLOBAL.BINLOG_CHECKSUM = @binlog_checksum_saved;
+SET @@GLOBAL.BINLOG_CHECKSUM = @binlog_checksum_saved;
+# End of test

mysql-test/suite/galera/t/binlog_checksum.test

+--source include/galera_cluster.inc
+--source include/have_innodb.inc
+
+--echo # On node_1
+--connection node_1
+SET @binlog_checksum_saved= @@GLOBAL.BINLOG_CHECKSUM;
+SET @@GLOBAL.BINLOG_CHECKSUM=CRC32;
+
+--echo # On node_2
+--connection node_2
+SET @binlog_checksum_saved= @@GLOBAL.BINLOG_CHECKSUM;
+SET @@GLOBAL.BINLOG_CHECKSUM=CRC32;
+
+USE test;
+CREATE TABLE t1(c1 INT PRIMARY KEY) ENGINE=INNODB;
+INSERT INTO t1 VALUES (1), (2), (3), (4), (5);
+SELECT * FROM t1;
+SELECT * FROM test.t1;
+
+--echo
+--echo # On node_2
+--connection node_2
+SELECT * FROM test.t1;
+
+--let $galera_diff_statement = SELECT * FROM t1
+--source include/galera_diff.inc
+
+# Cleanup
+DROP TABLE t1;
+--connection node_1
+SET @@GLOBAL.BINLOG_CHECKSUM = @binlog_checksum_saved;
+--connection node_2
+SET @@GLOBAL.BINLOG_CHECKSUM = @binlog_checksum_saved;
+
+--source include/galera_end.inc
+--echo # End of test

sql/sql_class.cc

@@ -1000,6 +1000,7 @@ THD::THD()
    wsrep_applier(is_applier),
    wsrep_applier_closing(FALSE),
    wsrep_client_thread(0),
+   wsrep_apply_format(0),
    wsrep_apply_toi(false),
 #endif
    m_parser_state(NULL),

sql/sql_class.h

@@ -2389,6 +2389,7 @@ public:
   const char*               wsrep_TOI_pre_query; /* a query to apply before 
 						    the actual TOI query */
   size_t                    wsrep_TOI_pre_query_len;
+  void*                     wsrep_apply_format;
   bool                      wsrep_apply_toi; /* applier processing in TOI */
 #endif /* WITH_WSREP */
   /**

sql/wsrep_applier.cc

@@ -17,7 +17,6 @@
 #include "wsrep_binlog.h" // wsrep_dump_rbr_buf()
 
 #include "log_event.h" // EVENT_LEN_OFFSET, etc.
-
 #include "wsrep_applier.h"
 
 /*
@@ -64,7 +63,25 @@ err:
 #include "rpl_rli.h"     // class Relay_log_info;
 #include "sql_base.h"    // close_temporary_table()
 
-extern const Format_description_log_event *wsrep_format_desc;
+static inline void
+wsrep_set_apply_format(THD* thd, Format_description_log_event* ev)
+{
+  if (thd->wsrep_apply_format)
+  {
+      delete (Format_description_log_event*)thd->wsrep_apply_format;
+  }
+  thd->wsrep_apply_format= ev;
+}
+
+static inline Format_description_log_event*
+wsrep_get_apply_format(THD* thd)
+{
+  if (thd->wsrep_apply_format)
+  {
+    return (Format_description_log_event*) thd->wsrep_apply_format;
+  }
+  return thd->wsrep_rli->relay_log.description_event_for_exec;
+}
 
 static wsrep_cb_status_t wsrep_apply_events(THD*        thd,
                                             const void* events_buf,
@@ -98,7 +115,8 @@ static wsrep_cb_status_t wsrep_apply_events(THD*        thd,
   {
     int exec_res;
     int error = 0;
-    Log_event* ev=  wsrep_read_log_event(&buf, &buf_len, wsrep_format_desc);
+    Log_event* ev= wsrep_read_log_event(&buf, &buf_len,
+                                        wsrep_get_apply_format(thd));
 
     if (!ev)
     {
@@ -111,6 +129,9 @@ static wsrep_cb_status_t wsrep_apply_events(THD*        thd,
     typ= ev->get_type_code();
 
     switch (typ) {
+    case FORMAT_DESCRIPTION_EVENT:
+      wsrep_set_apply_format(thd, (Format_description_log_event*)ev);
+      continue;
     case WRITE_ROWS_EVENT:
     case UPDATE_ROWS_EVENT:
     case DELETE_ROWS_EVENT:
@@ -339,6 +360,7 @@ wsrep_cb_status_t wsrep_commit_cb(void*         const     ctx,
   else
     rcode = wsrep_rollback(thd, meta->gtid.seqno);
 
+  wsrep_set_apply_format(thd, NULL);
   thd->mdl_context.release_transactional_locks();
   free_root(thd->mem_root,MYF(MY_KEEP_PREALLOC));
   thd->tx_isolation= (enum_tx_isolation) thd->variables.tx_isolation;

sql/wsrep_mysqld.cc

@@ -28,7 +28,6 @@
 #include "log_event.h"
 #include <slave.h>
 
-Format_description_log_event *wsrep_format_desc = NULL;
 wsrep_t *wsrep                  = NULL;
 my_bool wsrep_emulate_bin_log   = FALSE; // activating parts of binlog interface
 
@@ -498,7 +497,6 @@ int wsrep_init()
 
   wsrep_ready_set(FALSE);
   assert(wsrep_provider);
-  wsrep_format_desc= new Format_description_log_event(4);
   wsrep_init_position();
 
   if ((rcode= wsrep_load(wsrep_provider, &wsrep, wsrep_log_cb)) != WSREP_OK)
@@ -718,8 +716,6 @@ void wsrep_deinit(bool free_options)
   provider_version[0]= '\0';
   provider_vendor[0]=  '\0';
 
-  delete wsrep_format_desc;
-  wsrep_format_desc= NULL;
   wsrep_inited= 0;
 
   if (free_options)
@@ -1133,6 +1129,12 @@ int wsrep_to_buf_helper(
     return 1;
 
   int ret(0);
+
+  Format_description_log_event *tmp_fd= new Format_description_log_event(4);
+  tmp_fd->checksum_alg= binlog_checksum_options;
+  tmp_fd->write(&tmp_io_cache);
+  delete tmp_fd;
+
   /* if there is prepare query, add event for it */
   if (thd->wsrep_TOI_pre_query)
   {