MDEV-19593 Split create_schema_table() into virtual methods in Type_handler

sql/field.h

@@ -1142,6 +1142,8 @@ public:
   {
     return Information_schema_character_attributes();
   }
+  virtual void update_data_type_statistics(Data_type_statistics *st) const
+  { }
   /*
     Caller beware: sql_type can change str.Ptr, so check
     ptr() to see if it changed if you are using your own buffer
@@ -3566,6 +3568,11 @@ public:
   my_decimal *val_decimal(my_decimal *);
   int cmp(const uchar *,const uchar *);
   void sort_string(uchar *buff,uint length);
+  void update_data_type_statistics(Data_type_statistics *st) const
+  {
+    st->m_fixed_string_count++;
+    st->m_fixed_string_total_length+= pack_length();
+  }
   void sql_type(String &str) const;
   uint is_equal(Create_field *new_field);
   virtual uchar *pack(uchar *to, const uchar *from,
@@ -3663,6 +3670,11 @@ public:
            !compression_method() == !from->compression_method() &&
            length_bytes == ((Field_varstring*) from)->length_bytes;
   }
+  void update_data_type_statistics(Data_type_statistics *st) const
+  {
+    st->m_variable_string_count++;
+    st->m_variable_string_total_length+= pack_length();
+  }
   int  store(const char *to,size_t length,CHARSET_INFO *charset);
   using Field_str::store;
   double val_real(void);
@@ -3869,6 +3881,10 @@ public:
     uint32 chars= octets / field_charset->mbminlen;
     return Information_schema_character_attributes(octets, chars);
   }
+  void update_data_type_statistics(Data_type_statistics *st) const
+  {
+    st->m_blob_count++;
+  }
   void make_send_field(Send_field *);
   Copy_func *get_copy_func(const Field *from) const
   {
@@ -4346,6 +4362,10 @@ public:
   {
     return Information_schema_numeric_attributes(field_length);
   }
+  void update_data_type_statistics(Data_type_statistics *st) const
+  {
+    st->m_uneven_bit_length+= field_length & 7;
+  }
   uint size_of() const { return sizeof(*this); }
   int reset(void) { 
     bzero(ptr, bytes_in_rec); 

sql/item.h

@@ -1506,7 +1506,6 @@ public:
 
   virtual Field *get_tmp_table_field() { return 0; }
   virtual Field *create_field_for_create_select(TABLE *table);
-  virtual Field *create_field_for_schema(THD *thd, TABLE *table);
   virtual const char *full_name() const { return name.str ? name.str : "???"; }
   const char *field_name_or_null()
   { return real_item()->type() == Item::FIELD_ITEM ? name.str : NULL; }
@@ -4492,46 +4491,6 @@ public:
 };
 
 
-class Item_return_date_time :public Item_partition_func_safe_string
-{
-  enum_field_types date_time_field_type;
-public:
-  Item_return_date_time(THD *thd, const LEX_CSTRING &name_arg,
-                        enum_field_types field_type_arg, uint dec_arg= 0):
-    Item_partition_func_safe_string(thd, name_arg,
-                                    0/*length is not important*/,
-                                    &my_charset_bin),
-    date_time_field_type(field_type_arg)
-  { decimals= dec_arg; }
-  const Type_handler *type_handler() const
-  {
-    return Type_handler::get_handler_by_field_type(date_time_field_type);
-  }
-};
-
-
-class Item_blob :public Item_partition_func_safe_string
-{
-public:
-  Item_blob(THD *thd, const LEX_CSTRING &name_arg, uint length):
-    Item_partition_func_safe_string(thd, name_arg, length, &my_charset_bin)
-  { }
-  enum Type type() const { return TYPE_HOLDER; }
-  const Type_handler *type_handler() const
-  {
-    return Type_handler::blob_type_handler(max_length);
-  }
-  const Type_handler *real_type_handler() const
-  {
-    // Should not be called, Item_blob is used for SHOW purposes only.
-    DBUG_ASSERT(0);
-    return &type_handler_varchar;
-  }
-  Field *create_field_for_schema(THD *thd, TABLE *table)
-  { return tmp_table_field_from_field_type(table); }
-};
-
-
 /**
   Item_empty_string -- is a utility class to put an item into List<Item>
   which is then used in protocol.send_result_set_metadata() when sending SHOW output to

sql/sql_profile.h

@@ -19,7 +19,7 @@
 class Item;
 struct TABLE_LIST;
 class THD;
-typedef struct st_field_info ST_FIELD_INFO;
+struct ST_FIELD_INFO;
 typedef struct st_schema_table ST_SCHEMA_TABLE;
 
 extern ST_FIELD_INFO query_profile_statistics_info[];

sql/sql_select.h

@@ -2419,6 +2419,13 @@ TABLE *create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
 			ulonglong select_options, ha_rows rows_limit,
                         const LEX_CSTRING *alias, bool do_not_open=FALSE,
                         bool keep_row_order= FALSE);
+TABLE *create_tmp_table_for_schema(THD *thd, TMP_TABLE_PARAM *param,
+                                   const ST_SCHEMA_TABLE &schema_table,
+                                   const MY_BITMAP &bitmap,
+                                   longlong select_options,
+                                   const LEX_CSTRING &alias,
+                                   bool keep_row_order);
+
 void free_tmp_table(THD *thd, TABLE *entry);
 bool create_internal_tmp_table_from_heap(THD *thd, TABLE *table,
                                          TMP_ENGINE_COLUMNDEF *start_recinfo,

sql/sql_show.cc

@@ -8164,13 +8164,11 @@ mark_all_fields_used_in_query(THD *thd,
 TABLE *create_schema_table(THD *thd, TABLE_LIST *table_list)
 {
   uint field_count;
-  Item *item, *all_items;
+  Item *all_items;
   TABLE *table;
-  List<Item> field_list;
   ST_SCHEMA_TABLE *schema_table= table_list->schema_table;
   ST_FIELD_INFO *fields_info= schema_table->fields_info;
   ST_FIELD_INFO *fields;
-  MEM_ROOT *mem_root= thd->mem_root;
   MY_BITMAP bitmap;
   my_bitmap_map *buf;
   DBUG_ENTER("create_schema_table");
@@ -8189,120 +8187,6 @@ TABLE *create_schema_table(THD *thd, TABLE_LIST *table_list)
 
   mark_all_fields_used_in_query(thd, fields_info, &bitmap, all_items);
 
-  for (field_count=0; fields_info->field_name; fields_info++)
-  {
-    switch (fields_info->field_type) {
-    case MYSQL_TYPE_TINY:
-    case MYSQL_TYPE_LONG:
-    case MYSQL_TYPE_SHORT:
-    case MYSQL_TYPE_LONGLONG:
-    case MYSQL_TYPE_INT24:
-      if (!(item= new (mem_root)
-            Item_return_int(thd, fields_info->field_name,
-                            fields_info->field_length,
-                            fields_info->field_type,
-                            fields_info->value)))
-      {
-        DBUG_RETURN(0);
-      }
-      item->unsigned_flag= (fields_info->field_flags & MY_I_S_UNSIGNED);
-      break;
-    case MYSQL_TYPE_DATE:
-      if (!(item=new (mem_root)
-            Item_return_date_time(thd, fields_info->get_name(),
-                                  fields_info->field_type)))
-        DBUG_RETURN(0);
-      break;
-    case MYSQL_TYPE_TIME:
-      if (!(item=new (mem_root)
-            Item_return_date_time(thd, fields_info->get_name(),
-                                  fields_info->field_type)))
-        DBUG_RETURN(0);
-      break;
-    case MYSQL_TYPE_TIMESTAMP:
-    case MYSQL_TYPE_DATETIME:
-      if (!(item=new (mem_root)
-            Item_return_date_time(thd, fields_info->get_name(),
-                                  fields_info->field_type,
-                                  fields_info->field_length)))
-        DBUG_RETURN(0);
-      item->decimals= fields_info->field_length;
-      break;
-    case MYSQL_TYPE_FLOAT:
-    case MYSQL_TYPE_DOUBLE:
-      if ((item= new (mem_root)
-           Item_float(thd, fields_info->field_name, 0.0,
-                      NOT_FIXED_DEC,
-                      fields_info->field_length)) == NULL)
-        DBUG_RETURN(NULL);
-      break;
-    case MYSQL_TYPE_DECIMAL:
-    case MYSQL_TYPE_NEWDECIMAL:
-      if (!(item= new (mem_root)
-            Item_decimal(thd, (longlong) fields_info->value, false)))
-      {
-        DBUG_RETURN(0);
-      }
-      /*
-        Create a type holder, as we want the type of the item to defined
-        the type of the object, not the value
-      */
-      if (!(item= new (mem_root) Item_type_holder(thd, item)))
-        DBUG_RETURN(0);
-      item->unsigned_flag= (fields_info->field_flags & MY_I_S_UNSIGNED);
-      item->decimals= fields_info->field_length%10;
-      item->max_length= (fields_info->field_length/100)%100;
-      if (item->unsigned_flag == 0)
-        item->max_length+= 1;
-      if (item->decimals > 0)
-        item->max_length+= 1;
-      item->set_name(thd, fields_info->get_name());
-      break;
-    case MYSQL_TYPE_TINY_BLOB:
-    case MYSQL_TYPE_MEDIUM_BLOB:
-    case MYSQL_TYPE_LONG_BLOB:
-    case MYSQL_TYPE_BLOB:
-      if (bitmap_is_set(&bitmap, field_count))
-      {
-        if (!(item= new (mem_root)
-              Item_blob(thd, fields_info->get_name(),
-                        fields_info->field_length)))
-        {
-          DBUG_RETURN(0);
-        }
-      }
-      else
-      {
-        if (!(item= new (mem_root)
-              Item_empty_string(thd, "", 0, system_charset_info)))
-        {
-          DBUG_RETURN(0);
-        }
-        item->set_name(thd, fields_info->get_name());
-      }
-      break;
-    default:
-    {
-      bool show_field;
-      /* Don't let unimplemented types pass through. Could be a grave error. */
-      DBUG_ASSERT(fields_info->field_type == MYSQL_TYPE_STRING);
-
-      show_field= bitmap_is_set(&bitmap, field_count);
-      if (!(item= new (mem_root)
-            Item_empty_string(thd, "",
-                              show_field ? fields_info->field_length : 0,
-                              system_charset_info)))
-      {
-        DBUG_RETURN(0);
-      }
-      item->set_name(thd, fields_info->get_name());
-      break;
-    }
-    }
-    field_list.push_back(item, thd->mem_root);
-    item->maybe_null= (fields_info->field_flags & MY_I_S_MAYBE_NULL);
-    field_count++;
-  }
   TMP_TABLE_PARAM *tmp_table_param =
     (TMP_TABLE_PARAM*) (thd->alloc(sizeof(TMP_TABLE_PARAM)));
   tmp_table_param->init();
@@ -8311,11 +8195,13 @@ TABLE *create_schema_table(THD *thd, TABLE_LIST *table_list)
   tmp_table_param->schema_table= 1;
   SELECT_LEX *select_lex= table_list->select_lex;
   bool keep_row_order= is_show_command(thd);
-  if (!(table= create_tmp_table(thd, tmp_table_param,
+  if (!(table= create_tmp_table_for_schema(thd, tmp_table_param,
-                                field_list, (ORDER*) 0, 0, 0, 
+                                           *schema_table, bitmap,
-                                (select_lex->options | thd->variables.option_bits |
+                                           (select_lex->options |
-                                 TMP_TABLE_ALL_COLUMNS), HA_POS_ERROR,
+                                            thd->variables.option_bits |
-                                &table_list->alias, false, keep_row_order)))
+                                            TMP_TABLE_ALL_COLUMNS),
+                                            table_list->alias,
+                                            keep_row_order)))
     DBUG_RETURN(0);
   my_bitmap_map* bitmaps=
     (my_bitmap_map*) thd->alloc(bitmap_buffer_size(field_count));

sql/sql_type.cc

@@ -3436,6 +3436,196 @@ Field *Type_handler_set::make_table_field(const LEX_CSTRING *name,
                    attr.collation);
 }
 
+
+/*************************************************************************/
+
+Field *Type_handler_float::make_schema_field(TABLE *table,
+                                              const Record_addr &addr,
+                                              const ST_FIELD_INFO &def,
+                                              bool show_field) const
+{
+  Lex_cstring name(def.field_name);
+  return new (table->in_use->mem_root)
+     Field_float(addr.ptr(), def.field_length,
+                  addr.null_ptr(), addr.null_bit(),
+                  Field::NONE, &name,
+                  (uint8) NOT_FIXED_DEC,
+                  0/*zerofill*/, def.unsigned_flag());
+}
+
+
+Field *Type_handler_double::make_schema_field(TABLE *table,
+                                              const Record_addr &addr,
+                                              const ST_FIELD_INFO &def,
+                                              bool show_field) const
+{
+  Lex_cstring name(def.field_name);
+  return new (table->in_use->mem_root)
+     Field_double(addr.ptr(), def.field_length,
+                  addr.null_ptr(), addr.null_bit(),
+                  Field::NONE, &name,
+                  (uint8) NOT_FIXED_DEC,
+                  0/*zerofill*/, def.unsigned_flag());
+}
+
+
+Field *Type_handler_decimal_result::make_schema_field(TABLE *table,
+                                                      const Record_addr &addr,
+                                                      const ST_FIELD_INFO &def,
+                                                      bool show_field) const
+{
+  Lex_cstring name(def.field_name);
+  uint dec= def.field_length % 10;
+  uint prec= (def.field_length / 100) % 100;
+  DBUG_ASSERT(dec <= DECIMAL_MAX_SCALE);
+  uint32 len= my_decimal_precision_to_length(prec, dec, def.unsigned_flag());
+  return new (table->in_use->mem_root)
+     Field_new_decimal(addr.ptr(), len, addr.null_ptr(), addr.null_bit(),
+                       Field::NONE, &name,
+                       (uint8) dec, 0/*zerofill*/, def.unsigned_flag());
+}
+
+
+Field *Type_handler_blob_common::make_schema_field(TABLE *table,
+                                                   const Record_addr &addr,
+                                                   const ST_FIELD_INFO &def,
+                                                   bool show_field) const
+{
+  Lex_cstring name(def.field_name);
+  if (show_field)
+  {
+    return new (table->in_use->mem_root)
+       Field_blob(addr.ptr(), addr.null_ptr(), addr.null_bit(),
+                  Field::NONE, &name, table->s,
+                  length_bytes(),
+                  &my_charset_bin);
+  }
+  else
+    return new (table->in_use->mem_root)
+      Field_null(addr.ptr(), 0, Field::NONE, &name, &my_charset_bin);
+}
+
+
+Field *Type_handler_string::make_schema_field(TABLE *table,
+                                              const Record_addr &addr,
+                                              const ST_FIELD_INFO &def,
+                                              bool show_field) const
+{
+  DBUG_ASSERT(def.field_length);
+  Lex_cstring name(def.field_name);
+  uint32 octet_length= (uint32) def.field_length * 3;
+  if (def.field_length * 3 > MAX_FIELD_VARCHARLENGTH)
+  {
+    Field *field= new (table->in_use->mem_root)
+      Field_blob(addr.ptr(), addr.null_ptr(), addr.null_bit(), Field::NONE,
+                 &name, table->s, 4, system_charset_info);
+    if (field)
+      field->field_length= octet_length;
+    return field;
+  }
+  else if (show_field)
+  {
+    return new (table->in_use->mem_root)
+      Field_varstring(addr.ptr(), octet_length,
+                      HA_VARCHAR_PACKLENGTH(octet_length),
+                      addr.null_ptr(), addr.null_bit(),
+                      Field::NONE, &name,
+                      table->s, system_charset_info);
+  }
+  else
+    return new (table->in_use->mem_root)
+      Field_null(addr.ptr(), 0, Field::NONE, &name, system_charset_info);
+}
+
+
+Field *Type_handler_tiny::make_schema_field(TABLE *table,
+                                            const Record_addr &addr,
+                                            const ST_FIELD_INFO &def,
+                                            bool show_field) const
+{
+  Lex_cstring name(def.field_name);
+  return new (table->in_use->mem_root)
+           Field_tiny(addr.ptr(), def.field_length,
+                      addr.null_ptr(), addr.null_bit(), Field::NONE, &name,
+                      0/*zerofill*/, def.unsigned_flag());
+}
+
+
+Field *Type_handler_short::make_schema_field(TABLE *table,
+                                             const Record_addr &addr,
+                                             const ST_FIELD_INFO &def,
+                                             bool show_field) const
+{
+  Lex_cstring name(def.field_name);
+  return new (table->in_use->mem_root)
+           Field_short(addr.ptr(), def.field_length,
+                       addr.null_ptr(), addr.null_bit(), Field::NONE, &name,
+                       0/*zerofill*/, def.unsigned_flag());
+}
+
+
+Field *Type_handler_long::make_schema_field(TABLE *table,
+                                            const Record_addr &addr,
+                                            const ST_FIELD_INFO &def,
+                                            bool show_field) const
+{
+  Lex_cstring name(def.field_name);
+  return new (table->in_use->mem_root)
+           Field_long(addr.ptr(), def.field_length,
+                      addr.null_ptr(), addr.null_bit(), Field::NONE, &name,
+                      0/*zerofill*/, def.unsigned_flag());
+}
+
+
+Field *Type_handler_longlong::make_schema_field(TABLE *table,
+                                                const Record_addr &addr,
+                                                const ST_FIELD_INFO &def,
+                                                bool show_field) const
+{
+  Lex_cstring name(def.field_name);
+  return new (table->in_use->mem_root)
+           Field_longlong(addr.ptr(), def.field_length,
+                          addr.null_ptr(), addr.null_bit(), Field::NONE, &name,
+                          0/*zerofill*/, def.unsigned_flag());
+}
+
+
+Field *Type_handler_date_common::make_schema_field(TABLE *table,
+                                                   const Record_addr &addr,
+                                                   const ST_FIELD_INFO &def,
+                                                   bool show_field) const
+{
+  Lex_cstring name(def.field_name);
+  return new (table->in_use->mem_root)
+           Field_newdate(addr.ptr(), addr.null_ptr(), addr.null_bit(),
+                         Field::NONE, &name);
+}
+
+
+Field *Type_handler_time_common::make_schema_field(TABLE *table,
+                                                   const Record_addr &addr,
+                                                   const ST_FIELD_INFO &def,
+                                                   bool show_field) const
+{
+  Lex_cstring name(def.field_name);
+  return new_Field_time(table->in_use->mem_root,
+                        addr.ptr(), addr.null_ptr(), addr.null_bit(),
+                        Field::NONE, &name, def.fsp());
+}
+
+
+Field *Type_handler_datetime_common::make_schema_field(TABLE *table,
+                                                       const Record_addr &addr,
+                                                       const ST_FIELD_INFO &def,
+                                                       bool show_field) const
+{
+  Lex_cstring name(def.field_name);
+  return new_Field_datetime(table->in_use->mem_root,
+                             addr.ptr(), addr.null_ptr(), addr.null_bit(),
+                             Field::NONE, &name, def.fsp());
+}
+
+
 /*************************************************************************/
 
 /*

sql/sql_type.h

@@ -81,6 +81,7 @@ struct TABLE;
 struct SORT_FIELD_ATTR;
 class Vers_history_point;
 class Virtual_column_info;
+struct ST_FIELD_INFO;
 
 #define my_charset_numeric      my_charset_latin1
 
@@ -110,6 +111,34 @@ enum scalar_comparison_op
 };
 
 
+class Data_type_statistics
+{
+public:
+  uint m_uneven_bit_length;
+  uint m_fixed_string_total_length;
+  uint m_fixed_string_count;
+  uint m_variable_string_total_length;
+  uint m_variable_string_count;
+  uint m_blob_count;
+  Data_type_statistics()
+   :m_uneven_bit_length(0),
+    m_fixed_string_total_length(0),
+    m_fixed_string_count(0),
+    m_variable_string_total_length(0),
+    m_variable_string_count(0),
+    m_blob_count(0)
+  { }
+  uint string_count() const
+  {
+    return m_fixed_string_count + m_variable_string_count;
+  }
+  uint string_total_length() const
+  {
+    return m_fixed_string_total_length + m_variable_string_total_length;
+  }
+};
+
+
 class Native: public Binary_string
 {
 public:
@@ -3422,6 +3451,14 @@ public:
                                    const Record_addr &addr,
                                    const Type_all_attributes &attr,
                                    TABLE *table) const;
+  virtual Field *make_schema_field(TABLE *table,
+                                   const Record_addr &addr,
+                                   const ST_FIELD_INFO &def,
+                                   bool show_field) const
+  {
+    DBUG_ASSERT(0);
+    return NULL;
+  }
   virtual Field *
   make_table_field_from_def(TABLE_SHARE *share,
                             MEM_ROOT *mem_root,
@@ -4192,6 +4229,10 @@ public:
   }
   bool subquery_type_allows_materialization(const Item *inner,
                                             const Item *outer) const;
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Field *make_num_distinct_aggregator_field(MEM_ROOT *, const Item *) const;
   void make_sort_key(uchar *to, Item *item, const SORT_FIELD_ATTR *sort_field,
                      Sort_param *param) const;
@@ -4759,6 +4800,10 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Field *make_table_field_from_def(TABLE_SHARE *share,
                                    MEM_ROOT *mem_root,
                                    const LEX_CSTRING *name,
@@ -4804,6 +4849,10 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Field *make_table_field_from_def(TABLE_SHARE *share,
                                    MEM_ROOT *mem_root,
                                    const LEX_CSTRING *name,
@@ -4849,6 +4898,10 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Field *make_table_field_from_def(TABLE_SHARE *share,
                                    MEM_ROOT *mem_root,
                                    const LEX_CSTRING *name,
@@ -4909,6 +4962,10 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Field *make_table_field_from_def(TABLE_SHARE *share,
                                    MEM_ROOT *mem_root,
                                    const LEX_CSTRING *name,
@@ -5108,6 +5165,10 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Field *make_table_field_from_def(TABLE_SHARE *share,
                                    MEM_ROOT *mem_root,
                                    const LEX_CSTRING *name,
@@ -5156,6 +5217,10 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Field *make_table_field_from_def(TABLE_SHARE *share,
                                    MEM_ROOT *mem_root,
                                    const LEX_CSTRING *name,
@@ -5188,6 +5253,10 @@ public:
   {
     return MYSQL_TIMESTAMP_TIME;
   }
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Item_literal *create_literal_item(THD *thd, const char *str, size_t length,
                                     CHARSET_INFO *cs, bool send_error) const;
   Item *create_typecast_item(THD *thd, Item *item,
@@ -5353,6 +5422,10 @@ public:
   {
     return true;
   }
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Item_literal *create_literal_item(THD *thd, const char *str, size_t length,
                                     CHARSET_INFO *cs, bool send_error) const;
   Item *create_typecast_item(THD *thd, Item *item,
@@ -5446,6 +5519,10 @@ public:
   {
     return true;
   }
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Item *create_typecast_item(THD *thd, Item *item,
                              const Type_cast_attributes &attr) const;
   void Column_definition_implicit_upgrade(Column_definition *c) const;
@@ -5817,6 +5894,10 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Field *make_table_field_from_def(TABLE_SHARE *share,
                                    MEM_ROOT *mem_root,
                                    const LEX_CSTRING *name,
@@ -5925,6 +6006,7 @@ class Type_handler_blob_common: public Type_handler_longstr
 {
 public:
   virtual ~Type_handler_blob_common() { }
+  virtual uint length_bytes() const= 0;
   Field *make_conversion_table_field(TABLE *, uint metadata,
                                      const Field *target) const;
   const Type_handler *type_handler_for_tmp_table(const Item *item) const
@@ -5955,6 +6037,10 @@ public:
                                        Item **items, uint nitems) const;
   void Item_param_setup_conversion(THD *thd, Item_param *) const;
 
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
   Field *make_table_field_from_def(TABLE_SHARE *share,
                                    MEM_ROOT *mem_root,
                                    const LEX_CSTRING *name,
@@ -5970,6 +6056,7 @@ class Type_handler_tiny_blob: public Type_handler_blob_common
   static const Name m_name_tinyblob;
 public:
   virtual ~Type_handler_tiny_blob() {}
+  uint length_bytes() const { return 1; }
   const Name name() const { return m_name_tinyblob; }
   enum_field_types field_type() const { return MYSQL_TYPE_TINY_BLOB; }
   uint32 calc_pack_length(uint32 length) const;
@@ -5986,6 +6073,7 @@ class Type_handler_medium_blob: public Type_handler_blob_common
   static const Name m_name_mediumblob;
 public:
   virtual ~Type_handler_medium_blob() {}
+  uint length_bytes() const { return 3; }
   const Name name() const { return m_name_mediumblob; }
   enum_field_types field_type() const { return MYSQL_TYPE_MEDIUM_BLOB; }
   uint32 calc_pack_length(uint32 length) const;
@@ -6002,6 +6090,7 @@ class Type_handler_long_blob: public Type_handler_blob_common
   static const Name m_name_longblob;
 public:
   virtual ~Type_handler_long_blob() {}
+  uint length_bytes() const { return 4; }
   const Name name() const { return m_name_longblob; }
   enum_field_types field_type() const { return MYSQL_TYPE_LONG_BLOB; }
   uint32 calc_pack_length(uint32 length) const;
@@ -6020,6 +6109,7 @@ class Type_handler_blob: public Type_handler_blob_common
   static const Name m_name_blob;
 public:
   virtual ~Type_handler_blob() {}
+  uint length_bytes() const { return 2; }
   const Name name() const { return m_name_blob; }
   enum_field_types field_type() const { return MYSQL_TYPE_BLOB; }
   uint32 calc_pack_length(uint32 length) const;

sql/table.h

@@ -1670,7 +1670,7 @@ bool fk_modifies_child(enum_fk_option opt);
 #define OPEN_FRM_ONLY   1U               // open FRM file only
 #define OPEN_FULL_TABLE 2U               // open FRM,MYD, MYI files
 
-typedef struct st_field_info
+struct ST_FIELD_INFO
 {
   /** 
       This is used as column name. 
@@ -1712,7 +1712,13 @@ typedef struct st_field_info
   {
     return LEX_CSTRING({old_name, strlen(old_name)});
   }
-} ST_FIELD_INFO;
+  bool unsigned_flag() const { return field_flags & MY_I_S_UNSIGNED; }
+  uint fsp() const
+  {
+    DBUG_ASSERT(field_length <= TIME_SECOND_PART_DIGITS);
+    return field_length;
+  }
+};
 
 
 struct TABLE_LIST;