MDEV-31130 INSERT-SELECT with many when/case/if conditions running forever

recursive column definitions in stacked materialized tables causes issues.
detect depth of walk in the item tree and terminate if too deep.

sql/item.h

@@ -1868,7 +1868,8 @@ class Item: public Value_source,
     return type_handler()->charset_for_protocol(this);
   };
 
-  virtual bool walk(Item_processor processor, bool walk_subquery, void *arg)
+  virtual bool walk(Item_processor processor, bool walk_subquery,
+      void *arg, uint depth= 0)
   {
     return (this->*processor)(arg);
   }
@@ -2595,15 +2596,17 @@ class Item_args
   Item **args, *tmp_arg[2];
   uint arg_count;
   void set_arguments(THD *thd, List<Item> &list);
-  bool walk_args(Item_processor processor, bool walk_subquery, void *arg)
+  bool walk_args(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth )
   {
     for (uint i= 0; i < arg_count; i++)
     {
-      if (args[i]->walk(processor, walk_subquery, arg))
+      if (args[i]->walk(processor, walk_subquery, arg, depth+1))
         return true;
     }
     return false;
   }
+
   bool transform_args(THD *thd, Item_transformer transformer, uchar *arg);
   void propagate_equal_fields(THD *, const Item::Context &, COND_EQUAL *);
   bool excl_dep_on_table(table_map tab_map)
@@ -5294,12 +5297,20 @@ class Item_func_or_sum: public Item_result_field,
   Item_func_or_sum(THD *thd, List<Item> &list):
     Item_result_field(thd), Item_args(thd, list) { }
   bool with_subquery() const { DBUG_ASSERT(fixed); return m_with_subquery; }
-  bool walk(Item_processor processor, bool walk_subquery, void *arg)
+
+#define MAX_WALK_DEPTH 70
+  bool walk(Item_processor processor, bool walk_subquery, void *arg, uint depth)
   {
-    if (walk_args(processor, walk_subquery, arg))
+    if (depth > MAX_WALK_DEPTH)
+    {
+      my_error( ER_DERIVED_RECURSION_LIMIT, MYF(0), MAX_WALK_DEPTH, "derived limit" );
+      return true;
+    }
+    if (walk_args(processor, walk_subquery, arg, depth+1))
       return true;
     return (this->*processor)(arg);
   }
+
   /*
     This method is used for debug purposes to print the name of an
     item to the debug log. The second use of this method is as
@@ -5488,10 +5499,11 @@ class Item_ref :public Item_ident,
   }
 
   bool is_json_type() { return (*ref)->is_json_type(); }
-  bool walk(Item_processor processor, bool walk_subquery, void *arg)
+  bool walk(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth= 0)
   { 
     if (ref && *ref)
-      return (*ref)->walk(processor, walk_subquery, arg) ||
+      return (*ref)->walk(processor, walk_subquery, arg, depth+1) ||
              (this->*processor)(arg); 
     else
       return FALSE;
@@ -5788,9 +5800,10 @@ class Item_cache_wrapper :public Item_result_field,
   }
   bool const_item() const { return orig_item->const_item(); }
   table_map not_null_tables() const { return orig_item->not_null_tables(); }
-  bool walk(Item_processor processor, bool walk_subquery, void *arg)
+  bool walk(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth= 0)
   {
-    return orig_item->walk(processor, walk_subquery, arg) ||
+    return orig_item->walk(processor, walk_subquery, arg, depth+1) ||
       (this->*processor)(arg);
   }
   bool enumerate_field_refs_processor(void *arg)
@@ -5899,9 +5912,10 @@ class Item_direct_view_ref :public Item_direct_ref
     return (*ref)->const_item() && (null_ref_table == NO_NULL_TABLE);
   }
   TABLE *get_null_ref_table() const { return null_ref_table; }
-  bool walk(Item_processor processor, bool walk_subquery, void *arg)
+  bool walk(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth= 0)
   { 
-    return (*ref)->walk(processor, walk_subquery, arg) ||
+    return (*ref)->walk(processor, walk_subquery, arg, depth+1) ||
            (this->*processor)(arg);
   }
   bool view_used_tables_processor(void *arg) 
@@ -6277,9 +6291,10 @@ class Item_copy :public Item,
   virtual double val_real() = 0;
   virtual longlong val_int() = 0;
   virtual int save_in_field(Field *field, bool no_conversions) = 0;
-  bool walk(Item_processor processor, bool walk_subquery, void *args)
+  bool walk(Item_processor processor, bool walk_subquery, void *args,
+      uint depth= 0)
   {
-    return (item->walk(processor, walk_subquery, args)) ||
+    return (item->walk(processor, walk_subquery, args, depth+1)) ||
       (this->*processor)(args);
   }
 };
@@ -6546,9 +6561,10 @@ class Item_default_value : public Item_field
   bool check_func_default_processor(void *arg) { return true; }
   bool register_field_in_read_map(void *arg);
 
-  bool walk(Item_processor processor, bool walk_subquery, void *args)
+  bool walk(Item_processor processor, bool walk_subquery, void *args,
+      uint depth= 0)
   {
-    return (arg && arg->walk(processor, walk_subquery, args)) ||
+    return (arg && arg->walk(processor, walk_subquery, args, depth+1)) ||
       (this->*processor)(args);
   }
 
@@ -6714,9 +6730,10 @@ class Item_insert_value : public Item_field
 
   Item_field *field_for_view_update() { return 0; }
 
-  bool walk(Item_processor processor, bool walk_subquery, void *args)
+  bool walk(Item_processor processor, bool walk_subquery, void *args,
+      uint depth= 0)
   {
-    return arg->walk(processor, walk_subquery, args) ||
+    return arg->walk(processor, walk_subquery, args, depth+1) ||
 	    (this->*processor)(args);
   }
   bool check_partition_func_processor(void *int_arg) {return TRUE;}
@@ -6972,11 +6989,12 @@ class Item_cache: public Item_fixed_hybrid,
     return example->is_expensive_processor(arg);
   }
   virtual void set_null();
-  bool walk(Item_processor processor, bool walk_subquery, void *arg)
+  bool walk(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth= 0)
   {
     if (arg == STOP_PTR)
       return FALSE;
-    if (example && example->walk(processor, walk_subquery, arg))
+    if (example && example->walk(processor, walk_subquery, arg, depth+1))
       return TRUE;
     return (this->*processor)(arg);
   }
@@ -7682,9 +7700,10 @@ class Item_direct_ref_to_item : public Item_direct_ref
   { m_item->update_used_tables(); }
   bool const_item() const { return m_item->const_item(); }
   table_map not_null_tables() const { return m_item->not_null_tables(); }
-  bool walk(Item_processor processor, bool walk_subquery, void *arg)
+  bool walk(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth= 0)
   {
-    return m_item->walk(processor, walk_subquery, arg) ||
+    return m_item->walk(processor, walk_subquery, arg, depth+1) ||
       (this->*processor)(arg);
   }
   bool enumerate_field_refs_processor(void *arg)

sql/item_cmpfunc.cc

@@ -2529,7 +2529,8 @@ void Item_func_nullif::split_sum_func(THD *thd, Ref_ptr_array ref_pointer_array,
 
 
 bool Item_func_nullif::walk(Item_processor processor,
-                            bool walk_subquery, void *arg)
+                            bool walk_subquery, void *arg,
+      uint depth)
 {
   /*
     No needs to iterate through args[2] when it's just a copy of args[0].
@@ -2538,7 +2539,7 @@ bool Item_func_nullif::walk(Item_processor processor,
   uint tmp_count= arg_count == 2 || args[0] == args[2] ? 2 : 3;
   for (uint i= 0; i < tmp_count; i++)
   {
-    if (args[i]->walk(processor, walk_subquery, arg))
+    if (args[i]->walk(processor, walk_subquery, arg, depth+1))
       return true;
   }
   return (this->*processor)(arg);
@@ -5030,14 +5031,15 @@ void Item_cond::fix_after_pullout(st_select_lex *new_parent, Item **ref,
 }
 
 
-bool Item_cond::walk(Item_processor processor, bool walk_subquery, void *arg)
+bool Item_cond::walk(Item_processor processor, bool walk_subquery, void *arg,
+    uint depth)
 {
   List_iterator_fast<Item> li(list);
   Item *item;
   while ((item= li++))
-    if (item->walk(processor, walk_subquery, arg))
+    if (item->walk(processor, walk_subquery, arg, depth+1))
       return 1;
-  return Item_func::walk(processor, walk_subquery, arg);
+  return Item_func::walk(processor, walk_subquery, arg, depth+1);
 }
 
 /**
@@ -7126,16 +7128,17 @@ bool Item_equal::fix_length_and_dec()
 }
 
 
-bool Item_equal::walk(Item_processor processor, bool walk_subquery, void *arg)
+bool Item_equal::walk(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth)
 {
   Item *item;
   Item_equal_fields_iterator it(*this);
   while ((item= it++))
   {
-    if (item->walk(processor, walk_subquery, arg))
+    if (item->walk(processor, walk_subquery, arg, depth+1))
       return 1;
   }
-  return Item_func::walk(processor, walk_subquery, arg);
+  return Item_func::walk(processor, walk_subquery, arg, depth+1);
 }
 
 

sql/item_cmpfunc.h

@@ -1264,7 +1264,8 @@ class Item_func_nullif :public Item_func_case_expression
   my_decimal *decimal_op(my_decimal *);
   bool native_op(THD *thd, Native *to);
   bool fix_length_and_dec();
-  bool walk(Item_processor processor, bool walk_subquery, void *arg);
+  bool walk(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth= 0);
   const char *func_name() const { return "nullif"; }
   void print(String *str, enum_query_type query_type);
   void split_sum_func(THD *thd, Ref_ptr_array ref_pointer_array, 
@@ -2784,10 +2785,10 @@ class Item_func_like :public Item_bool_func2
     return this;
   }
 
-  bool walk(Item_processor processor, bool walk_subquery, void *arg)
+  bool walk(Item_processor processor, bool walk_subquery, void *arg, uint depth)
   {
-    return walk_args(processor, walk_subquery, arg)
-      ||   escape_item->walk(processor, walk_subquery, arg)
+    return walk_args(processor, walk_subquery, arg, depth+1)
+      ||   escape_item->walk(processor, walk_subquery, arg, depth+1)
       ||  (this->*processor)(arg);
   }
 
@@ -3014,7 +3015,8 @@ class Item_cond :public Item_bool_func
   void top_level_item() { abort_on_null=1; }
   bool top_level() { return abort_on_null; }
   void copy_andor_arguments(THD *thd, Item_cond *item);
-  bool walk(Item_processor processor, bool walk_subquery, void *arg);
+  bool walk(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth= 0);
   Item *do_transform(THD *thd, Item_transformer transformer, uchar *arg, bool toplevel);
   Item *transform(THD *thd, Item_transformer transformer, uchar *arg)
   {
@@ -3215,7 +3217,8 @@ class Item_equal: public Item_bool_func
                       uint *and_level, table_map usable_tables,
                       SARGABLE_PARAM **sargables);
   SEL_TREE *get_mm_tree(RANGE_OPT_PARAM *param, Item **cond_ptr);
-  bool walk(Item_processor processor, bool walk_subquery, void *arg);
+  bool walk(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth= 0);
   Item *transform(THD *thd, Item_transformer transformer, uchar *arg);
   virtual void print(String *str, enum_query_type query_type);
   const Type_handler *compare_type_handler() const { return m_compare_handler; }

sql/item_row.h

@@ -113,9 +113,10 @@ class Item_row: public Item_fixed_hybrid,
   table_map not_null_tables() const { return not_null_tables_cache; }
   virtual void print(String *str, enum_query_type query_type);
 
-  bool walk(Item_processor processor, bool walk_subquery, void *arg)
+  bool walk(Item_processor processor, bool walk_subquery, void *arg, 
+      uint depth= 0)
   {
-    if (walk_args(processor, walk_subquery, arg))
+    if (walk_args(processor, walk_subquery, arg, depth+1))
       return true;
     return (this->*processor)(arg);
   }

sql/item_subselect.cc

@@ -668,7 +668,7 @@ int walk_items_for_table_list(Item_processor processor,
 
 
 bool Item_subselect::walk(Item_processor processor, bool walk_subquery,
-                          void *argument)
+                          void *argument, uint depth)
 {
   if (!(unit->uncacheable & ~UNCACHEABLE_DEPENDENT) && engine->is_executed() &&
       !unit->describe)

sql/item_subselect.h

@@ -241,7 +241,8 @@ class Item_subselect :public Item_result_field,
   */
   virtual void reset_value_registration() {}
   enum_parsing_place place() { return parsing_place; }
-  bool walk(Item_processor processor, bool walk_subquery, void *arg);
+  bool walk(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth= 0);
   bool mark_as_eliminated_processor(void *arg);
   bool eliminate_subselect_processor(void *arg);
   bool enumerate_field_refs_processor(void *arg);
@@ -753,10 +754,11 @@ class Item_in_subselect :public Item_exists_subselect
     DBUG_VOID_RETURN;
   }
 
-  bool walk(Item_processor processor, bool walk_subquery, void *arg)
+  bool walk(Item_processor processor, bool walk_subquery, void *arg,
+      uint depth= 0)
   {
-    return left_expr->walk(processor, walk_subquery, arg) ||
-           Item_subselect::walk(processor, walk_subquery, arg);
+    return left_expr->walk(processor, walk_subquery, arg, depth+1) ||
+           Item_subselect::walk(processor, walk_subquery, arg, depth+1);
   }
 
   bool exists2in_processor(void *opt_arg __attribute__((unused)))

sql/share/errmsg-utf8.txt

@@ -9090,3 +9090,6 @@ ER_PERIOD_CONSTRAINT_DROP
 ER_TOO_LONG_KEYPART 42000 S1009
         chi "指定的索引部分太长；最大索引部分长度为 %u 个字节"
         eng "Specified key part was too long; max key part length is %u bytes"
+ER_DERIVED_RECURSION_LIMIT
+        chi "例程超出派生合并递归限制 %d（设置 derived_merge=off)"
+        eng "Derived Merged Recursive limit %d was exceeded for routine (set derived_merge=off)"

sql/sql_base.cc

@@ -6262,7 +6262,13 @@ find_field_in_table_ref(THD *thd, TABLE_LIST *table_list,
           else
           {
             if (thd->column_usage == MARK_COLUMNS_READ)
-              it->walk(&Item::register_field_in_read_map, 0, 0);
+            {
+              if (it->walk(&Item::register_field_in_read_map, 0, 0))
+              {
+                // something went wrong, 
+                fld= nullptr;
+              }
+            }
             else
               it->walk(&Item::register_field_in_write_map, 0, 0);
           }