MDEV-10045: Server crashes in Time_and_counter_tracker::incr_loops

Do not set 'optimized' flag until whole optimization procedure is finished.

1 files changed, 30 insertions, 9 deletions

diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index 301856ea3b8..2999e01d166 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -560,6 +560,21 @@ void Item_subselect::recalc_used_tables(st_select_lex *new_parent,
 bool Item_subselect::is_expensive()
 {
   double examined_rows= 0;
+  bool all_are_simple= true;
+
+  /* check extremely simple select */
+  if (!unit->first_select()->next_select()) // no union
+  {
+    /*
+      such single selects works even without optimization because
+      can not makes loops
+    */
+    SELECT_LEX *sl= unit->first_select();
+    JOIN *join = sl->join;
+    if (join && !join->tables_list && !sl->first_inner_unit())
+      return false;
+  }
+
 
   for (SELECT_LEX *sl= unit->first_select(); sl; sl= sl->next_select())
   {
@@ -569,23 +584,27 @@ bool Item_subselect::is_expensive()
     if (!cur_join)
       return true;
 
-    /* very simple subquery */
-    if (!cur_join->tables_list && !sl->first_inner_unit())
-      return false;
-
     /*
       If the subquery is not optimised or in the process of optimization
       it supposed to be expensive
     */
-    if (!cur_join->optimized)
+    if (cur_join->optimization_state != JOIN::OPTIMIZATION_DONE)
       return true;
 
+    if (!cur_join->tables_list && !sl->first_inner_unit())
+      continue;
+
     /*
       Subqueries whose result is known after optimization are not expensive.
       Such subqueries have all tables optimized away, thus have no join plan.
     */
     if ((cur_join->zero_result_cause || !cur_join->tables_list))
-      return false;
+      continue;
+
+    /*
+      This is not simple SELECT in union so we can not go by simple condition
+    */
+    all_are_simple= false;
 
     /*
       If a subquery is not optimized we cannot estimate its cost. A subquery is
@@ -606,7 +625,8 @@ bool Item_subselect::is_expensive()
     examined_rows+= cur_join->get_examined_rows();
   }
 
-  return (examined_rows > thd->variables.expensive_subquery_limit);
+  return !all_are_simple &&
+    (examined_rows > thd->variables.expensive_subquery_limit);
 }
 
 
@@ -3672,7 +3692,7 @@ int subselect_single_select_engine::exec()
   SELECT_LEX *save_select= thd->lex->current_select;
   thd->lex->current_select= select_lex;
 
-  if (!join->optimized)
+  if (join->optimization_state == JOIN::NOT_OPTIMIZED)
   {
     SELECT_LEX_UNIT *unit= select_lex->master_unit();
 
@@ -5321,7 +5341,8 @@ int subselect_hash_sj_engine::exec()
   */
   thd->lex->current_select= materialize_engine->select_lex;
   /* The subquery should be optimized, and materialized only once. */
-  DBUG_ASSERT(materialize_join->optimized && !is_materialized);
+  DBUG_ASSERT(materialize_join->optimization_state == JOIN::OPTIMIZATION_DONE &&
+              !is_materialized);
   materialize_join->exec();
   if ((res= MY_TEST(materialize_join->error || thd->is_fatal_error ||
                     thd->is_error())))