SQL: optimized fields fix for NOT NULL [fixes #226]

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

-create table t(
+create table t (
 a int,
 b int without system versioning
 ) with system versioning;
@@ -36,12 +36,14 @@ a	b
 3	NULL
 Warnings:
 Warning	4075	Attempt to read unversioned field `b` in historical query
+Warning	4075	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	4075	Attempt to read unversioned field `b` in historical query
+Warning	4075	Attempt to read unversioned field `b` in historical query
 select * from t group by a having a=2 system_time as of timestamp now(6);
 a	b
 Warnings:
@@ -50,6 +52,7 @@ select * from t group by b having b=2 system_time as of timestamp now(6);
 a	b
 Warnings:
 Warning	4075	Attempt to read unversioned field `b` in historical query
+Warning	4075	Attempt to read unversioned field `b` in historical query
 select a from t where b=2 system_time as of timestamp now(6);
 a
 Warnings:
@@ -68,8 +71,56 @@ select count(*), b from t group by b having b=NULL system_time as of timestamp n
 count(*)	b
 Warnings:
 Warning	4075	Attempt to read unversioned field `b` in historical query
+Warning	4075	Attempt to read unversioned field `b` in historical query
 select a, b from t;
 a	b
 1	2
 3	4
+select count(*) from t for system_time as of timestamp now(6) group by b;
+count(*)
+2
+Warnings:
+Warning	4075	Attempt to read unversioned field `b` in historical query
+select * from t for system_time as of timestamp now(6) group by b having b=2;
+a	b
+Warnings:
+Warning	4075	Attempt to read unversioned field `b` in historical query
+Warning	4075	Attempt to read unversioned field `b` in historical query
+select a from t for system_time as of timestamp now(6) where b=2;
+a
+Warnings:
+Warning	4075	Attempt to read unversioned field `b` in historical query
+select a from t for system_time as of timestamp now(6) where b=NULL;
+a
+Warnings:
+Warning	4075	Attempt to read unversioned field `b` in historical query
+select a from t for system_time as of timestamp now(6) where b is NULL;
+a
+1
+3
+Warnings:
+Warning	4075	Attempt to read unversioned field `b` in historical query
+select count(*), b from t for system_time as of timestamp now(6) group by b having b=NULL;
+count(*)	b
+Warnings:
+Warning	4075	Attempt to read unversioned field `b` in historical query
+Warning	4075	Attempt to read unversioned field `b` in historical query
+create or replace table t (
+a int,
+b int not null without system versioning
+) with system versioning;
+insert into t values (1, 2), (3, 4);
+select * from t for system_time as of timestamp now(6);
+a	b
+1	NULL
+3	NULL
+Warnings:
+Warning	4075	Attempt to read unversioned field `b` in historical query
+select * from t for system_time as of timestamp now(6) where b is NULL;
+a	b
+1	NULL
+3	NULL
+Warnings:
+Warning	4075	Attempt to read unversioned field `b` in historical query
+Warning	4075	Attempt to read unversioned field `b` in historical query
 drop table t;

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

-create table t(
+create table t (
   a int,
   b int without system versioning
 ) with system versioning;
@@ -20,4 +20,21 @@ select a from t where b is NULL system_time as of timestamp now(6);
 select count(*), b from t group by b having b=NULL system_time as of timestamp now(6);
 select a, b from t;
 
+select count(*) from t for system_time as of timestamp now(6) group by b;
+select * from t for system_time as of timestamp now(6) group by b having b=2;
+select a from t for system_time as of timestamp now(6) where b=2;
+select a from t for system_time as of timestamp now(6) where b=NULL;
+select a from t for system_time as of timestamp now(6) where b is NULL;
+select count(*), b from t for system_time as of timestamp now(6) group by b having b=NULL;
+
+create or replace table t (
+  a int,
+  b int not null without system versioning
+) with system versioning;
+
+insert into t values (1, 2), (3, 4);
+
+select * from t for system_time as of timestamp now(6);
+select * from t for system_time as of timestamp now(6) where b is NULL;
+
 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), force_null(false), part_of_sortkey(0),
+  part_of_key_not_clustered(0), 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

@@ -703,8 +703,6 @@ 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, ...
 
@@ -1090,8 +1088,6 @@ 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

@@ -2759,20 +2759,6 @@ void Item_field::set_field(Field *field_par)
   fixed= 1;
   if (field->table->s->tmp_table == SYSTEM_TMP_TABLE)
     any_privileges= 0;
-
-  field->force_null= false;
-  if (field->flags & VERS_OPTIMIZED_UPDATE_FLAG && context &&
-      ((field->table->pos_in_table_list &&
-        field->table->pos_in_table_list->vers_conditions) ||
-       (context->select_lex && context->select_lex->vers_conditions)))
-  {
-    field->force_null= true;
-    push_warning_printf(
-        current_thd, Sql_condition::WARN_LEVEL_WARN,
-        ER_NON_VERSIONED_FIELD_IN_VERSIONED_QUERY,
-        ER_THD(current_thd, ER_NON_VERSIONED_FIELD_IN_VERSIONED_QUERY),
-        field_name);
-  }
 }
 
 
@@ -10757,6 +10743,30 @@ bool Item_field::exclusive_dependence_on_grouping_fields_processor(void *arg)
   return true;
 }
 
+Item *Item_field::vers_optimized_fields_transformer(THD *thd, uchar *)
+{
+  if (!field)
+    return this;
+
+  if (field->flags & VERS_OPTIMIZED_UPDATE_FLAG && context &&
+      ((field->table->pos_in_table_list &&
+        field->table->pos_in_table_list->vers_conditions) ||
+       (context->select_lex && context->select_lex->vers_conditions)))
+  {
+    push_warning_printf(
+        current_thd, Sql_condition::WARN_LEVEL_WARN,
+        ER_NON_VERSIONED_FIELD_IN_VERSIONED_QUERY,
+        ER_THD(current_thd, ER_NON_VERSIONED_FIELD_IN_VERSIONED_QUERY),
+        field_name);
+
+    Item *null_item= new (thd->mem_root) Item_null(thd);
+    if (null_item)
+      return null_item;
+  }
+
+  return this;
+}
+
 void Item::register_in(THD *thd)
 {
   next= thd->free_list;

sql/item.h

@@ -1655,6 +1655,8 @@ class Item: public Value_source,
 
   virtual Item_field *field_for_view_update() { return 0; }
 
+  virtual Item *vers_optimized_fields_transformer(THD *thd, uchar *)
+  { return this; }
   virtual Item *neg_transformer(THD *thd) { return NULL; }
   virtual Item *update_value_transformer(THD *thd, uchar *select_arg)
   { return this; }
@@ -2750,6 +2752,7 @@ class Item_field :public Item_ident
   uint32 max_display_length() const { return field->max_display_length(); }
   Item_field *field_for_view_update() { return this; }
   int fix_outer_field(THD *thd, Field **field, Item **reference);
+  virtual Item *vers_optimized_fields_transformer(THD *thd, uchar *);
   virtual Item *update_value_transformer(THD *thd, uchar *select_arg);
   Item *derived_field_transformer_for_having(THD *thd, uchar *arg);
   Item *derived_field_transformer_for_where(THD *thd, uchar *arg);

sql/sql_select.cc

@@ -1380,6 +1380,46 @@ JOIN::prepare(TABLE_LIST *tables_init,
   if (!procedure && result && result->prepare(fields_list, unit_arg))
     goto err;					/* purecov: inspected */
 
+  if (!thd->stmt_arena->is_stmt_prepare())
+  {
+    bool have_versioned_tables= false;
+    for (TABLE_LIST *table= tables_list; table; table= table->next_local)
+    {
+      if (table->table && table->table->versioned())
+      {
+        have_versioned_tables= true;
+        break;
+      }
+    }
+
+    if (have_versioned_tables)
+    {
+      Item_transformer transformer= &Item::vers_optimized_fields_transformer;
+
+      if (conds)
+      {
+        conds= conds->transform(thd, transformer, NULL);
+      }
+
+      for (ORDER *ord= order; ord; ord= ord->next)
+      {
+        ord->item_ptr= (*ord->item)->transform(thd, transformer, NULL);
+        ord->item= &ord->item_ptr;
+      }
+
+      for (ORDER *ord= group_list; ord; ord= ord->next)
+      {
+        ord->item_ptr= (*ord->item)->transform(thd, transformer, NULL);
+        ord->item= &ord->item_ptr;
+      }
+
+      if (having)
+      {
+        having= having->transform(thd, transformer, NULL);
+      }
+    }
+  }
+
   unit= unit_arg;
   if (prepare_stage2())
     goto err;
@@ -3827,6 +3867,16 @@ void JOIN::exec_inner()
   result->send_result_set_metadata(
                  procedure ? procedure_fields_list : *fields,
                  Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF);
+
+  {
+    List_iterator<Item> it(*columns_list);
+    while (Item *item= it++)
+    {
+      Item_transformer transformer= &Item::vers_optimized_fields_transformer;
+      it.replace(item->transform(thd, transformer, NULL));
+    }
+  }
+
   error= do_select(this, procedure);
   /* Accumulate the counts from all join iterations of all join parts. */
   thd->inc_examined_row_count(join_examined_rows);