BUG#28976 Mixing trans and non-trans tables in one transaction results in incorrect

binlog

Mixing transactional (T) and non-transactional (N) tables on behalf of a
transaction may lead to inconsistencies among masters and slaves in STATEMENT
mode. The problem stems from the fact that although modifications done to
non-transactional tables on behalf of a transaction become immediately visible
to other connections they do not immediately get to the binary log and therefore
consistency is broken. Although there may be issues in mixing T and M tables in
STATEMENT mode, there are safe combinations that clients find useful.

In this bug, we fix the following issue. Mixing N and T tables in multi-level
(e.g. a statement that fires a trigger) or multi-table table statements (e.g.
update t1, t2...) were not handled correctly. In such cases, it was not possible
to distinguish when a T table was updated if the sequence of changes was N and T.
In a nutshell, just the flag "modified_non_trans_table" was not enough to reflect
that both a N and T tables were changed. To circumvent this issue, we check if an
engine is registered in the handler's list and changed something which means that
a T table was modified.

Check WL 2687 for a full-fledged patch that will make the use of either the MIXED or
ROW modes completely safe.

mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result:
  Truncate statement is wrapped in BEGIN/COMMIT.
mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result:
  Truncate statement is wrapped in BEGIN/COMMIT.

1 files changed, 21 insertions, 1 deletions

diff --git a/sql/log.cc b/sql/log.cc
index bb81d0c723e..282312d28e2 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -1264,6 +1264,25 @@ int LOGGER::set_handlers(uint error_log_printer,
   return 0;
 }
 
+/** 
+    This function checks if a transactional talbe was updated by the
+    current statement.
+
+    @param thd The client thread that executed the current statement.
+    @return
+      @c true if a transactional table was updated, @false otherwise.
+*/
+static bool stmt_has_updated_trans_table(THD *thd)
+{
+  Ha_trx_info *ha_info;
+
+  for (ha_info= thd->transaction.stmt.ha_list; ha_info; ha_info= ha_info->next())
+  {
+    if (ha_info->is_trx_read_write() && ha_info->ht() != binlog_hton)
+      return (TRUE);
+  }
+  return (FALSE);
+}
 
  /*
   Save position of binary log transaction cache.
@@ -4060,7 +4079,8 @@ bool MYSQL_BIN_LOG::write(Log_event *event_info)
         (binlog_trx_data*) thd_get_ha_data(thd, binlog_hton);
       IO_CACHE *trans_log= &trx_data->trans_log;
       my_off_t trans_log_pos= my_b_tell(trans_log);
-      if (event_info->get_cache_stmt() || trans_log_pos != 0)
+      if (event_info->get_cache_stmt() || trans_log_pos != 0 ||
+          stmt_has_updated_trans_table(thd))
       {
         DBUG_PRINT("info", ("Using trans_log: cache: %d, trans_log_pos: %lu",
                             event_info->get_cache_stmt(),