BUG#55387: binlog.binlog_tmp_table crashes the server

           sporadically

There are two problems:

1. When closing temporary tables, during the THD clean up - and
   after the session connection was already closed, there is a
   chance we can push an error into the THD diagnostics area, if
   the writing of the implicit DROP event to the binary log fails
   for some reason. As a consequence an assertion can be
   triggered, because at that point the diagnostics area is
   already set.

2. Using push_warning with MYSQL_ERROR::WARN_LEVEL_ERROR is a 
   bug.

Given that close_temporary_tables is mostly called from
THD::cleanup - ie, with the session already closed, we fix
problem #1 by allowing the diagnostics area to be
overwritten. There is one other place in the code that calls
close_temporary_tables - while applying Start_log_event_v3. To
cover that case, we make close_temporary_tables to return the
error, thus, propagating upwards in the stack.

To fix problem #2, we replace push_warning with sql_print_error.

sql/log_event.cc:
  Added handling of error returned by close_temporary_tables to
  Start_log_event_v3::do_apply_event.
sql/sql_base.cc:
  Three changes to close_temporary_tables:
  1. it returns a boolean now (instead of void)
  2. it uses sql_print_error instead of push_warning when writing to
     binary log fails
  3. we set can_overwrite_status before writing to the binary log,
     thence not risking triggering an assertion by any other push
     into diagnostics area happening inside mysql_bin_log.write.
sql/sql_base.h:
  Changed the interface of close_temporary_tables so that it returns
  bool instead of void.

1 files changed, 1 insertions, 1 deletions

diff --git a/sql/sql_base.h b/sql/sql_base.h
index 20a068e27d7..eed535f5cdc 100644
--- a/sql/sql_base.h
+++ b/sql/sql_base.h
@@ -222,7 +222,7 @@ int decide_logging_format(THD *thd, TABLE_LIST *tables);
 void free_io_cache(TABLE *entry);
 void intern_close_table(TABLE *entry);
 bool close_thread_table(THD *thd, TABLE **table_ptr);
-void close_temporary_tables(THD *thd);
+bool close_temporary_tables(THD *thd);
 TABLE_LIST *unique_table(THD *thd, TABLE_LIST *table, TABLE_LIST *table_list,
                          bool check_alias);
 int drop_temporary_table(THD *thd, TABLE_LIST *table_list);