Fixed a problem where the temp table of a materialized subquery

was not cleaned up between PS re-executions. The reason was two-fold:
- a merge with mysql-6.0 missed select_union::cleanup() that should
  have cleaned up the temp table, and
- the subclass of select_union used by materialization didn't call
  the base class cleanup() method.

1 files changed, 16 insertions, 0 deletions

diff --git a/sql/sql_union.cc b/sql/sql_union.cc
index ee9ff833726..1080b45d60d 100644
--- a/sql/sql_union.cc
+++ b/sql/sql_union.cc
@@ -136,6 +136,22 @@ select_union::create_result_table(THD *thd_arg, List<Item> *column_types,
 }
 
 
+/**
+  Reset and empty the temporary table that stores the materialized query result.
+
+  @note The cleanup performed here is exactly the same as for the two temp
+  tables of JOIN - exec_tmp_table_[1 | 2].
+*/
+
+void select_union::cleanup()
+{
+  table->file->extra(HA_EXTRA_RESET_STATE);
+  table->file->ha_delete_all_rows();
+  free_io_cache(table);
+  filesort_free_buffers(table,0);
+}
+
+
 /*
   initialization procedures before fake_select_lex preparation()