Merge branch '10.3' into 10.4

1 files changed, 25 insertions, 0 deletions

diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 6509f25a41f..a91b4571b21 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -1871,6 +1871,9 @@ JOIN::optimize_inner()
   DEBUG_SYNC(thd, "before_join_optimize");
 
   THD_STAGE_INFO(thd, stage_optimizing);
+#ifndef DBUG_OFF
+  dbug_join_tab_array_size= 0;
+#endif
 
   set_allowed_join_cache_types();
   need_distinct= TRUE;
@@ -3104,6 +3107,9 @@ setup_subq_exit:
     {
       if (!(join_tab= (JOIN_TAB*) thd->alloc(sizeof(JOIN_TAB))))
         DBUG_RETURN(1);
+#ifndef DBUG_OFF
+      dbug_join_tab_array_size= 1;
+#endif
       need_tmp= 1;
     }
     if (make_aggr_tables_info())
@@ -3416,6 +3422,7 @@ bool JOIN::make_aggr_tables_info()
   {
     aggr_tables++;
     curr_tab= join_tab + exec_join_tab_cnt();
+    DBUG_ASSERT(curr_tab - join_tab < dbug_join_tab_array_size);
     bzero((void*)curr_tab, sizeof(JOIN_TAB));
     curr_tab->ref.key= -1;
     if (only_const_tables())
@@ -3544,6 +3551,7 @@ bool JOIN::make_aggr_tables_info()
 
       curr_tab++;
       aggr_tables++;
+      DBUG_ASSERT(curr_tab - join_tab < dbug_join_tab_array_size);
       bzero((void*)curr_tab, sizeof(JOIN_TAB));
       curr_tab->ref.key= -1;
 
@@ -10426,6 +10434,23 @@ bool JOIN::get_best_combination()
 
   if (aggr_tables > 2)
     aggr_tables= 2;
+
+#ifndef DBUG_OFF
+  dbug_join_tab_array_size= top_join_tab_count + aggr_tables;
+#endif
+  /*
+    NOTE: The above computation of aggr_tables can produce wrong result because some
+    of the variables it uses may change their values after we leave this function.
+    Known examples:
+     - Dangerous: using_outer_summary_function=false at this point. Added
+       DBUG_ASSERT below to demonstrate. Can this cause us to allocate less
+       space than we would need?
+     - Not dangerous: select_distinct can be true here but be assigned false
+       afterwards.
+  */
+  aggr_tables= 2;
+  DBUG_ASSERT(!tmp_table_param.using_outer_summary_function);
+
   if (!(join_tab= (JOIN_TAB*) thd->alloc(sizeof(JOIN_TAB)*
                                         (top_join_tab_count + aggr_tables))))
     DBUG_RETURN(TRUE);