SQL: NULL instead of optimized fields in versioned queries

mysql-test/suite/versioning/r/optimized_fields.result

+create table t(
+a int,
+b int without system versioning
+) with system versioning;
+insert into t values(1, 2);
+insert into t values(3, 4);
+select * from t;
+a	b
+1	2
+3	4
+select a from t for system_time as of timestamp now(6);
+a
+1
+3
+select a, b, b+0 from t for system_time as of timestamp now(6);
+a	b	b+0
+1	NULL	NULL
+3	NULL	NULL
+Warnings:
+Warning	4050	Attempt to read unversioned field 'b' in historical query
+select * from t for system_time as of timestamp now(6);
+a	b
+1	NULL
+3	NULL
+Warnings:
+Warning	4050	Attempt to read unversioned field 'b' in historical query
+select count(*) from t group by b for system_time as of timestamp now(6);
+count(*)
+2
+Warnings:
+Warning	4050	Attempt to read unversioned field 'b' in historical query
+select * from t for system_time as of timestamp now(6) order by b asc;
+a	b
+1	NULL
+3	NULL
+Warnings:
+Warning	4050	Attempt to read unversioned field 'b' in historical query
+select * from t for system_time as of timestamp now(6) order by b desc;
+a	b
+1	NULL
+3	NULL
+Warnings:
+Warning	4050	Attempt to read unversioned field 'b' in historical query
+select * from t group by a having a=2 for system_time as of timestamp now(6);
+a	b
+Warnings:
+Warning	4050	Attempt to read unversioned field 'b' in historical query
+select * from t group by b having b=2 for system_time as of timestamp now(6);
+a	b
+Warnings:
+Warning	4050	Attempt to read unversioned field 'b' in historical query
+select a from t where b=2 for system_time as of timestamp now(6);
+a
+Warnings:
+Warning	4050	Attempt to read unversioned field 'b' in historical query
+select a from t where b=NULL for system_time as of timestamp now(6);
+a
+Warnings:
+Warning	4050	Attempt to read unversioned field 'b' in historical query
+select count(*), b from t group by b having b=NULL for system_time as of timestamp now(6);
+count(*)	b
+Warnings:
+Warning	4050	Attempt to read unversioned field 'b' in historical query
+select a, b from t;
+a	b
+1	2
+3	4
+drop table t;

mysql-test/suite/versioning/t/optimized_fields.test

+create table t(
+  a int,
+  b int without system versioning
+) with system versioning;
+
+insert into t values(1, 2);
+insert into t values(3, 4);
+select * from t;
+select a from t for system_time as of timestamp now(6);
+select a, b, b+0 from t for system_time as of timestamp now(6);
+select * from t for system_time as of timestamp now(6);
+select count(*) from t group by b for system_time as of timestamp now(6);
+select * from t for system_time as of timestamp now(6) order by b asc;
+select * from t for system_time as of timestamp now(6) order by b desc;
+select * from t group by a having a=2 for system_time as of timestamp now(6);
+select * from t group by b having b=2 for system_time as of timestamp now(6);
+select a from t where b=2 for system_time as of timestamp now(6);
+select a from t where b=NULL for system_time as of timestamp now(6);
+select count(*), b from t group by b having b=NULL for system_time as of timestamp now(6);
+select a, b from t;
+
+drop table t;

sql/field.cc

@@ -1631,7 +1631,7 @@ Field::Field(uchar *ptr_arg,uint32 length_arg,uchar *null_ptr_arg,
   :ptr(ptr_arg), null_ptr(null_ptr_arg), table(0), orig_table(0),
   table_name(0), field_name(field_name_arg), option_list(0),
   option_struct(0), key_start(0), part_of_key(0),
-  part_of_key_not_clustered(0), part_of_sortkey(0),
+  part_of_key_not_clustered(0), force_null(false), part_of_sortkey(0),
   unireg_check(unireg_check_arg), field_length(length_arg),
   null_bit(null_bit_arg), is_created_from_null_item(FALSE),
   read_stats(NULL), collected_stats(0), vcol_info(0), check_constraint(0),

sql/field.h

@@ -707,6 +707,8 @@ class Field: public Value_source
   /* Field is part of the following keys */
   key_map	key_start, part_of_key, part_of_key_not_clustered;
 
+  bool force_null;
+
   /*
     Bitmap of indexes that have records ordered by col1, ... this_field, ...
 
@@ -1089,6 +1091,8 @@ class Field: public Value_source
   virtual uint size_of() const =0;		// For new field
   inline bool is_null(my_ptrdiff_t row_offset= 0) const
   {
+    if (force_null)
+      return true;
     /*
       The table may have been marked as containing only NULL values
       for all fields if it is a NULL-complemented row of an OUTER JOIN

sql/item.cc

@@ -2759,6 +2759,21 @@ void Item_field::set_field(Field *field_par)
   fixed= 1;
   if (field->table->s->tmp_table == SYSTEM_TMP_TABLE)
     any_privileges= 0;
+
+  if (field->is_versioning_disabled() && context && context->select_lex &&
+      context->select_lex->vers_conditions.type !=
+          FOR_SYSTEM_TIME_UNSPECIFIED &&
+      !field->force_null)
+  {
+    DBUG_ASSERT(context->select_lex->parent_lex &&
+                context->select_lex->parent_lex->thd);
+    field->force_null= true;
+    THD *thd= context->select_lex->parent_lex->thd;
+    push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
+                        ER_NON_VERSIONED_FIELD_IN_VERSIONED_QUERY,
+                        ER_THD(thd, ER_NON_VERSIONED_FIELD_IN_VERSIONED_QUERY),
+                        field_name);
+  }
 }
 
 
@@ -5907,6 +5922,8 @@ void Item_field::cleanup()
     it will be linked correctly next time by name of field and table alias.
     I.e. we can drop 'field'.
    */
+  if (field)
+    field->force_null= false;
   field= 0;
   item_equal= NULL;
   null_value= FALSE;

sql/share/errmsg-utf8.txt

@@ -7543,3 +7543,6 @@ ER_VERS_TRX_ID_UNSUPPORTED
 
 ER_VERS_RANGE_UNITS_MISMATCH
         eng "Range units mismatch"
+
+ER_NON_VERSIONED_FIELD_IN_VERSIONED_QUERY
+        eng "Attempt to read unversioned field '%s' in historical query"