Backporting MDEV-15597 Add class Load_data_outvar and avoid using Item::STRING_ITEM for Item_user_var_as_out_param detection

This is a part of "MDEV-18045 Backporting the MDEV-15497 changes to 10.2 branch"

7 files changed, 256 insertions, 228 deletions

diff --git a/sql/field.cc b/sql/field.cc
index 18f99945645..080cf34c76d 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -1375,7 +1375,25 @@ bool Field::load_data_set_no_data(THD *thd, bool fixed_format)
 {
   reset();                  // Do not use the DEFAULT value
   if (fixed_format)
+  {
     set_notnull();
+    /*
+      We're loading a fixed format file, e.g.:
+        LOAD DATA INFILE 't1.txt' INTO TABLE t1 FIELDS TERMINATED BY '';
+      Suppose the file ended unexpectedly and no data was provided for an
+      auto-increment column in the current row.
+      Historically, if sql_mode=NO_AUTO_VALUE_ON_ZERO, then the column value
+      is set to 0 in such case (the next auto_increment value is not used).
+      This behaviour was introduced by the fix for "bug#12053" in mysql-4.1.
+      Note, loading a delimited file works differently:
+      "no data" is not converted to 0 on NO_AUTO_VALUE_ON_ZERO:
+      it's considered as equal to setting the column to NULL,
+      which is then replaced to the next auto_increment value.
+      This difference seems to be intentional.
+    */
+    if (this == table->next_number_field)
+      table->auto_increment_field_not_null= true;
+  }
   set_has_explicit_value(); // Do not auto-update this field
   return false;
 }
diff --git a/sql/item.cc b/sql/item.cc
index b4958c68be6..46420fd2c78 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -2645,6 +2645,31 @@ void Item_field::reset_field(Field *f)
 }
 
 
+void Item_field::load_data_print_for_log_event(THD *thd, String *to) const
+{
+  append_identifier(thd, to, name, (uint) strlen(name));
+}
+
+
+bool Item_field::load_data_set_no_data(THD *thd, const Load_data_param *param)
+{
+  if (field->load_data_set_no_data(thd, param->is_fixed_length()))
+    return true;
+  /*
+    TODO: We probably should not throw warning for each field.
+    But how about intention to always have the same number
+    of warnings in THD::cuted_fields (and get rid of cuted_fields
+    in the end ?)
+  */
+  thd->cuted_fields++;
+  push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
+                      ER_WARN_TOO_FEW_RECORDS,
+                      ER_THD(thd, ER_WARN_TOO_FEW_RECORDS),
+                      thd->get_stmt_da()->current_row_for_warning());
+  return false;
+}
+
+
 bool Item_field::enumerate_field_refs_processor(void *arg)
 {
   Field_enumerator *fe= (Field_enumerator*)arg;
diff --git a/sql/item.h b/sql/item.h
index b941c57896c..ac79e3437fb 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -1866,6 +1866,20 @@ public:
   {
     return 0;
   }
+
+  virtual Load_data_outvar *get_load_data_outvar()
+  {
+    return 0;
+  }
+  Load_data_outvar *get_load_data_outvar_or_error()
+  {
+    Load_data_outvar *dst= get_load_data_outvar();
+    if (dst)
+      return dst;
+    my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), name);
+    return NULL;
+  }
+
   /**
     Test whether an expression is expensive to compute. Used during
     optimization to avoid computing expensive expressions during this
@@ -2538,7 +2552,8 @@ public:
 };
 
 
-class Item_field :public Item_ident
+class Item_field :public Item_ident,
+                  public Load_data_outvar
 {
 protected:
   void set_field(Field *field);
@@ -2585,6 +2600,30 @@ public:
   bool val_bool_result();
   bool is_null_result();
   bool send(Protocol *protocol, String *str_arg);
+  Load_data_outvar *get_load_data_outvar()
+  {
+    return this;
+  }
+  bool load_data_set_null(THD *thd, const Load_data_param *param)
+  {
+    return field->load_data_set_null(thd);
+  }
+  bool load_data_set_value(THD *thd, const char *pos, uint length,
+                           const Load_data_param *param)
+  {
+    field->load_data_set_value(pos, length, param->charset());
+    return false;
+  }
+  bool load_data_set_no_data(THD *thd, const Load_data_param *param);
+  void load_data_print_for_log_event(THD *thd, String *to) const;
+  bool load_data_add_outvar(THD *thd, Load_data_param *param) const
+  {
+    return param->add_outvar_field(thd, field);
+  }
+  uint load_data_fixed_length() const
+  {
+    return field->field_length;
+  }
   void reset_field(Field *f);
   bool fix_fields(THD *, Item **);
   void fix_after_pullout(st_select_lex *new_parent, Item **ref, bool merge);
@@ -4379,6 +4418,10 @@ public:
   void cleanup();
   Item_field *field_for_view_update()
     { return (*ref)->field_for_view_update(); }
+  Load_data_outvar *get_load_data_outvar()
+  {
+    return (*ref)->get_load_data_outvar();
+  }
   virtual Ref_Type ref_type() { return REF; }
 
   // Row emulation: forwarding of ROW-related calls to ref
diff --git a/sql/item_func.cc b/sql/item_func.cc
index f755deea23b..28933aba7af 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -5751,7 +5751,9 @@ my_decimal* Item_user_var_as_out_param::val_decimal(my_decimal *decimal_buffer)
 }
 
 
-void Item_user_var_as_out_param::print_for_load(THD *thd, String *str)
+void Item_user_var_as_out_param::load_data_print_for_log_event(THD *thd,
+                                                               String *str)
+                                                               const
 {
   str->append('@');
   append_identifier(thd, str, name.str, name.length);
diff --git a/sql/item_func.h b/sql/item_func.h
index fea8c28f74f..7565a8d5a08 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -2038,13 +2038,43 @@ public:
   in List<Item> and desire to place this code somewhere near other functions
   working with user variables.
 */
-class Item_user_var_as_out_param :public Item
+class Item_user_var_as_out_param :public Item,
+                                  public Load_data_outvar
 {
   LEX_STRING name;
   user_var_entry *entry;
 public:
   Item_user_var_as_out_param(THD *thd, LEX_STRING a): Item(thd), name(a)
   { set_name(thd, a.str, 0, system_charset_info); }
+  Load_data_outvar *get_load_data_outvar()
+  {
+    return this;
+  }
+  bool load_data_set_null(THD *thd, const Load_data_param *param)
+  {
+    set_null_value(param->charset());
+    return false;
+  }
+  bool load_data_set_no_data(THD *thd, const Load_data_param *param)
+  {
+    set_null_value(param->charset());
+    return false;
+  }
+  bool load_data_set_value(THD *thd, const char *pos, uint length,
+                           const Load_data_param *param)
+  {
+    set_value(pos, length, param->charset());
+    return false;
+  }
+  void load_data_print_for_log_event(THD *thd, String *to) const;
+  bool load_data_add_outvar(THD *thd, Load_data_param *param) const
+  {
+    return param->add_outvar_user_var(thd);
+  }
+  uint load_data_fixed_length() const
+  {
+    return 0;
+  }
   /* We should return something different from FIELD_ITEM here */
   enum Type type() const { return STRING_ITEM;}
   double val_real();
@@ -2053,7 +2083,6 @@ public:
   my_decimal *val_decimal(my_decimal *decimal_buffer);
   /* fix_fields() binds variable name with its entry structure */
   bool fix_fields(THD *thd, Item **ref);
-  void print_for_load(THD *thd, String *str);
   void set_null_value(CHARSET_INFO* cs);
   void set_value(const char *str, uint length, CHARSET_INFO* cs);
   enum_field_types field_type() const { return MYSQL_TYPE_DOUBLE; }
diff --git a/sql/sql_load.cc b/sql/sql_load.cc
index 53b43ebb1f5..37ac168de43 100644
--- a/sql/sql_load.cc
+++ b/sql/sql_load.cc
@@ -134,11 +134,10 @@ static bool wsrep_load_data_split(THD *thd, const TABLE *table,
 #define WSREP_LOAD_DATA_SPLIT(thd,table,info) /* empty */
 #endif /* WITH_WSREP */
 
-class READ_INFO {
+class READ_INFO: public Load_data_param
+{
   File	file;
   String data;                          /* Read buffer */
-  uint fixed_length;                    /* Length of the fixed length record */
-  uint max_length;                      /* Max length of row */
   Term_string m_field_term;             /* FIELDS TERMINATED BY 'string' */
   Term_string m_line_term;              /* LINES TERMINATED BY 'string' */
   Term_string m_line_start;             /* LINES STARTING BY 'string' */
@@ -191,7 +190,7 @@ class READ_INFO {
   bool read_mbtail(String *str)
   {
     int chlen;
-    if ((chlen= my_charlen(read_charset, str->end() - 1, str->end())) == 1)
+    if ((chlen= my_charlen(charset(), str->end() - 1, str->end())) == 1)
       return false; // Single byte character found
     for (uint32 length0= str->length() - 1 ; MY_CS_IS_TOOSMALL(chlen); )
     {
@@ -202,7 +201,7 @@ class READ_INFO {
         return true; // EOF
       }
       str->append(chr);
-      chlen= my_charlen(read_charset, str->ptr() + length0, str->end());
+      chlen= my_charlen(charset(), str->ptr() + length0, str->end());
       if (chlen == MY_CS_ILSEQ)
       {
         /**
@@ -224,10 +223,9 @@ public:
   bool error,line_cuted,found_null,enclosed;
   uchar	*row_start,			/* Found row starts here */
 	*row_end;			/* Found row ends here */
-  CHARSET_INFO *read_charset;
   LOAD_FILE_IO_CACHE cache;
 
-  READ_INFO(THD *thd, File file, uint tot_length, CHARSET_INFO *cs,
+  READ_INFO(THD *thd, File file, const Load_data_param &param,
 	    String &field_term,String &line_start,String &line_term,
 	    String &enclosed,int escape,bool get_it_from_net, bool is_fifo);
   ~READ_INFO();
@@ -282,6 +280,31 @@ static bool write_execute_load_query_log_event(THD *, sql_exchange*, const
            char*, const char*, bool, enum enum_duplicates, bool, bool, int);
 #endif /* EMBEDDED_LIBRARY */
 
+
+bool Load_data_param::add_outvar_field(THD *thd, const Field *field)
+{
+  if (field->flags & BLOB_FLAG)
+  {
+    m_use_blobs= true;
+    m_fixed_length+= 256;  // Will be extended if needed
+  }
+  else
+    m_fixed_length+= field->field_length;
+  return false;
+}
+
+
+bool Load_data_param::add_outvar_user_var(THD *thd)
+{
+  if (m_is_fixed_length)
+  {
+    my_error(ER_LOAD_FROM_FIXED_SIZE_ROWS_TO_VAR, MYF(0));
+    return true;
+  }
+  return false;
+}
+
+
 /*
   Execute LOAD DATA query
 
@@ -313,8 +336,6 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   File file;
   TABLE *table= NULL;
   int error= 0;
-  String *field_term=ex->field_term,*escaped=ex->escaped;
-  String *enclosed=ex->enclosed;
   bool is_fifo=0;
 #ifndef EMBEDDED_LIBRARY
   killed_state killed_status;
@@ -343,7 +364,7 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   read_file_from_client  = 0; //server is always in the same process 
 #endif
 
-  if (escaped->length() > 1 || enclosed->length() > 1)
+  if (ex->escaped->length() > 1 || ex->enclosed->length() > 1)
   {
     my_message(ER_WRONG_FIELD_TERMINATORS,
                ER_THD(thd, ER_WRONG_FIELD_TERMINATORS),
@@ -352,8 +373,8 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   }
 
   /* Report problems with non-ascii separators */
-  if (!escaped->is_ascii() || !enclosed->is_ascii() ||
-      !field_term->is_ascii() ||
+  if (!ex->escaped->is_ascii() || !ex->enclosed->is_ascii() ||
+      !ex->field_term->is_ascii() ||
       !ex->line_term->is_ascii() || !ex->line_start->is_ascii())
   {
     push_warning(thd, Sql_condition::WARN_LEVEL_WARN,
@@ -450,39 +471,21 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   table->prepare_triggers_for_insert_stmt_or_event();
   table->mark_columns_needed_for_insert();
 
-  uint tot_length=0;
-  bool use_blobs= 0, use_vars= 0;
+  Load_data_param param(ex->cs ? ex->cs : thd->variables.collation_database,
+                        !ex->field_term->length() && !ex->enclosed->length());
   List_iterator_fast<Item> it(fields_vars);
   Item *item;
 
   while ((item= it++))
   {
-    Item *real_item= item->real_item();
-
-    if (real_item->type() == Item::FIELD_ITEM)
-    {
-      Field *field= ((Item_field*)real_item)->field;
-      if (field->flags & BLOB_FLAG)
-      {
-        use_blobs= 1;
-        tot_length+= 256;			// Will be extended if needed
-      }
-      else
-        tot_length+= field->field_length;
-    }
-    else if (item->type() == Item::STRING_ITEM)
-      use_vars= 1;
+    const Load_data_outvar *var= item->get_load_data_outvar_or_error();
+    if (!var || var->load_data_add_outvar(thd, &param))
+      DBUG_RETURN(true);
   }
-  if (use_blobs && !ex->line_term->length() && !field_term->length())
+  if (param.use_blobs() && !ex->line_term->length() && !ex->field_term->length())
   {
     my_message(ER_BLOBS_AND_NO_TERMINATED,
-               ER_THD(thd, ER_BLOBS_AND_NO_TERMINATED),
-	       MYF(0));
-    DBUG_RETURN(TRUE);
-  }
-  if (use_vars && !field_term->length() && !enclosed->length())
-  {
-    my_error(ER_LOAD_FROM_FIXED_SIZE_ROWS_TO_VAR, MYF(0));
+               ER_THD(thd, ER_BLOBS_AND_NO_TERMINATED), MYF(0));
     DBUG_RETURN(TRUE);
   }
 
@@ -572,13 +575,13 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   bzero((char*) &info,sizeof(info));
   info.ignore= ignore;
   info.handle_duplicates=handle_duplicates;
-  info.escape_char= (escaped->length() && (ex->escaped_given() ||
+  info.escape_char= (ex->escaped->length() && (ex->escaped_given() ||
                     !(thd->variables.sql_mode & MODE_NO_BACKSLASH_ESCAPES)))
-                    ? (*escaped)[0] : INT_MAX;
+                    ? (*ex->escaped)[0] : INT_MAX;
 
-  READ_INFO read_info(thd, file, tot_length,
-                      ex->cs ? ex->cs : thd->variables.collation_database,
-		      *field_term,*ex->line_start, *ex->line_term, *enclosed,
+  READ_INFO read_info(thd, file, param,
+                      *ex->field_term, *ex->line_start,
+                      *ex->line_term, *ex->enclosed,
 		      info.escape_char, read_file_from_client, is_fifo);
   if (read_info.error)
   {
@@ -639,14 +642,14 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
       error= read_xml_field(thd, info, table_list, fields_vars,
                             set_fields, set_values, read_info,
                             *(ex->line_term), skip_lines, ignore);
-    else if (!field_term->length() && !enclosed->length())
+    else if (read_info.is_fixed_length())
       error= read_fixed_length(thd, info, table_list, fields_vars,
                                set_fields, set_values, read_info,
 			       skip_lines, ignore);
     else
       error= read_sep_field(thd, info, table_list, fields_vars,
                             set_fields, set_values, read_info,
-			    *enclosed, skip_lines, ignore);
+                            *ex->enclosed, skip_lines, ignore);
 
     thd_proc_info(thd, "End bulk insert");
     if (!error)
@@ -850,14 +853,9 @@ static bool write_execute_load_query_log_event(THD *thd, sql_exchange* ex,
     {
       if (n++)
         query_str.append(", ");
-      if (item->real_type() == Item::FIELD_ITEM)
-        append_identifier(thd, &query_str, item->name, strlen(item->name));
-      else
-      {
-        /* Actually Item_user_var_as_out_param despite claiming STRING_ITEM. */
-        DBUG_ASSERT(item->type() == Item::STRING_ITEM);
-        ((Item_user_var_as_out_param *)item)->print_for_load(thd, &query_str);
-      }
+      const Load_data_outvar *var= item->get_load_data_outvar();
+      DBUG_ASSERT(var);
+      var->load_data_print_for_log_event(thd, &query_str);
     }
     query_str.append(")");
   }
@@ -905,9 +903,9 @@ read_fixed_length(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
                   ulong skip_lines, bool ignore_check_option_errors)
 {
   List_iterator_fast<Item> it(fields_vars);
-  Item_field *sql_field;
+  Item *item;
   TABLE *table= table_list->table;
-  bool err, progress_reports, auto_increment_field_not_null=false;
+  bool err, progress_reports;
   ulonglong counter, time_to_report_progress;
   DBUG_ENTER("read_fixed_length");
 
@@ -917,12 +915,6 @@ read_fixed_length(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
   if ((thd->progress.max_counter= read_info.file_length()) == ~(my_off_t) 0)
     progress_reports= 0;
 
-  while ((sql_field= (Item_field*) it++))
-  {
-    if (sql_field->field == table->next_number_field)
-      auto_increment_field_not_null= true;
-  }
-
   while (!read_info.read_fixed_length())
   {
     if (thd->killed)
@@ -958,36 +950,27 @@ read_fixed_length(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
 #endif
 
     restore_record(table, s->default_values);
-    /*
-      There is no variables in fields_vars list in this format so
-      this conversion is safe.
-    */
-    while ((sql_field= (Item_field*) it++))
+
+    while ((item= it++))
     {
-      Field *field= sql_field->field;                  
-      table->auto_increment_field_not_null= auto_increment_field_not_null;
+      Load_data_outvar *dst= item->get_load_data_outvar();
+      DBUG_ASSERT(dst);
       if (pos == read_info.row_end)
       {
-        if (field->load_data_set_no_data(thd, true))
+        if (dst->load_data_set_no_data(thd, &read_info))
           DBUG_RETURN(1);
-        thd->cuted_fields++;			/* Not enough fields */
-        push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
-                            ER_WARN_TOO_FEW_RECORDS,
-                            ER_THD(thd, ER_WARN_TOO_FEW_RECORDS),
-                            thd->get_stmt_da()->current_row_for_warning());
       }
       else
       {
-	uint length;
-	uchar save_chr;
-	if ((length=(uint) (read_info.row_end-pos)) >
-	    field->field_length)
-	  length=field->field_length;
-	save_chr=pos[length]; pos[length]='\0'; // Safeguard aganst malloc
-        field->load_data_set_value((char*) pos,length,read_info.read_charset);
-	pos[length]=save_chr;
-	if ((pos+=length) > read_info.row_end)
-	  pos= read_info.row_end;	/* Fills rest with space */
+        uint length, fixed_length= dst->load_data_fixed_length();
+        uchar save_chr;
+        if ((length=(uint) (read_info.row_end - pos)) > fixed_length)
+          length= fixed_length;
+        save_chr= pos[length]; pos[length]= '\0'; // Safeguard aganst malloc
+        dst->load_data_set_value(thd, (const char *) pos, length, &read_info);
+        pos[length]= save_chr;
+        if ((pos+= length) > read_info.row_end)
+          pos= read_info.row_end;               // Fills rest with space
       }
     }
     if (pos != read_info.row_end)
@@ -1087,8 +1070,6 @@ read_sep_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
     {
       uint length;
       uchar *pos;
-      Item_field *real_item;
-
       if (read_info.read_field())
 	break;
 
@@ -1099,48 +1080,22 @@ read_sep_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
       pos=read_info.row_start;
       length=(uint) (read_info.row_end-pos);
 
-      real_item= item->field_for_view_update();
+      Load_data_outvar *dst= item->get_load_data_outvar_or_error();
+      DBUG_ASSERT(dst);
 
       if ((!read_info.enclosed &&
            (enclosed_length && length == 4 &&
             !memcmp(pos, STRING_WITH_LEN("NULL")))) ||
 	  (length == 1 && read_info.found_null))
       {
-        if (item->type() == Item::STRING_ITEM)
-        {
-          ((Item_user_var_as_out_param *)item)->set_null_value(
-                                                  read_info.read_charset);
-        }
-        else if (!real_item)
-        {
-          my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), item->name);
+        if (dst->load_data_set_null(thd, &read_info))
           DBUG_RETURN(1);
-        }
-        else
-        {
-          DBUG_ASSERT(real_item->field->table == table);
-          if (real_item->field->load_data_set_null(thd))
-            DBUG_RETURN(1);
-	}
-
-	continue;
-      }
-
-      if (item->type() == Item::STRING_ITEM)
-      {
-        ((Item_user_var_as_out_param *)item)->set_value((char*) pos, length,
-                                                        read_info.read_charset);
-      }
-      else if (!real_item)
-      {
-        my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), item->name);
-        DBUG_RETURN(1);
       }
       else
       {
-        Field *field= real_item->field;
-        read_info.row_end[0]=0;			// Safe to change end marker
-        field->load_data_set_value((char*) pos, length, read_info.read_charset);
+        read_info.row_end[0]= 0;  // Safe to change end marker
+        if (dst->load_data_set_value(thd, (const char *) pos, length, &read_info))
+          DBUG_RETURN(1);
       }
     }
 
@@ -1161,34 +1116,10 @@ read_sep_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
 	break;
       for (; item ; item= it++)
       {
-        Item_field *real_item= item->field_for_view_update();
-        if (item->type() == Item::STRING_ITEM)
-        {
-          ((Item_user_var_as_out_param *)item)->set_null_value(
-                                                  read_info.read_charset);
-        }
-        else if (!real_item)
-        {
-          my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), item->name);
+        Load_data_outvar *dst= item->get_load_data_outvar_or_error();
+        DBUG_ASSERT(dst);
+        if (dst->load_data_set_no_data(thd, &read_info))
           DBUG_RETURN(1);
-        }
-        else
-        {
-          Field *field= real_item->field;
-          if (field->load_data_set_no_data(thd, false))
-            DBUG_RETURN(1);
-          /*
-            TODO: We probably should not throw warning for each field.
-            But how about intention to always have the same number
-            of warnings in THD::cuted_fields (and get rid of cuted_fields
-            in the end ?)
-          */
-          thd->cuted_fields++;
-          push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
-                              ER_WARN_TOO_FEW_RECORDS,
-                              ER_THD(thd, ER_WARN_TOO_FEW_RECORDS),
-                              thd->get_stmt_da()->current_row_for_warning());
-        }
       }
     }
 
@@ -1250,7 +1181,6 @@ read_xml_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
   Item *item;
   TABLE *table= table_list->table;
   bool no_trans_update_stmt;
-  CHARSET_INFO *cs= read_info.read_charset;
   DBUG_ENTER("read_xml_field");
   
   no_trans_update_stmt= !table->file->has_transactions();
@@ -1296,41 +1226,14 @@ read_xml_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
       
       while(tag && strcmp(tag->field.c_ptr(), item->name) != 0)
         tag= xmlit++;
-      
-      Item_field *real_item= item->field_for_view_update();
-      if (!tag) // found null
-      {
-        if (item->type() == Item::STRING_ITEM)
-          ((Item_user_var_as_out_param *) item)->set_null_value(cs);
-        else if (!real_item)
-        {
-          my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), item->name);
-          DBUG_RETURN(1);
-        }
-        else
-        {
-          DBUG_ASSERT(real_item->field->table == table);
-          if (real_item->field->load_data_set_null(thd))
-            DBUG_RETURN(1);
-        }
-        continue;
-      }
 
-      if (item->type() == Item::STRING_ITEM)
-        ((Item_user_var_as_out_param *) item)->set_value(
-                                                 (char *) tag->value.ptr(),
-                                                 tag->value.length(), cs);
-      else if (!real_item)
-      {
-        my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), item->name);
+      Load_data_outvar *dst= item->get_load_data_outvar_or_error();
+      DBUG_ASSERT(dst);
+      if (!tag ? dst->load_data_set_null(thd, &read_info) :
+                 dst->load_data_set_value(thd, tag->value.ptr(),
+                                          tag->value.length(),
+                                          &read_info))
         DBUG_RETURN(1);
-      }
-      else
-      {
-
-        Field *field= ((Item_field *)item)->field;
-        field->load_data_set_value(tag->value.ptr(), tag->value.length(), cs);
-      }
     }
     
     if (read_info.error)
@@ -1341,39 +1244,8 @@ read_xml_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
       skip_lines--;
       continue;
     }
-    
-    if (item)
-    {
-      /* Have not read any field, thus input file is simply ended */
-      if (item == fields_vars.head())
-        break;
-      
-      for ( ; item; item= it++)
-      {
-        Item_field *real_item= item->field_for_view_update();
-        if (item->type() == Item::STRING_ITEM)
-          ((Item_user_var_as_out_param *)item)->set_null_value(cs);
-        else if (!real_item)
-        {
-          my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), item->name);
-          DBUG_RETURN(1);
-        }
-        else
-        {
-          /*
-            QQ: We probably should not throw warning for each field.
-            But how about intention to always have the same number
-            of warnings in THD::cuted_fields (and get rid of cuted_fields
-            in the end ?)
-          */
-          thd->cuted_fields++;
-          push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
-                              ER_WARN_TOO_FEW_RECORDS,
-                              ER_THD(thd, ER_WARN_TOO_FEW_RECORDS),
-                              thd->get_stmt_da()->current_row_for_warning());
-        }
-      }
-    }
+
+    DBUG_ASSERT(!item);
 
     if (thd->killed ||
         fill_record_n_invoke_before_triggers(thd, table, set_fields, set_values,
@@ -1435,14 +1307,16 @@ READ_INFO::unescape(char chr)
 */
 
 
-READ_INFO::READ_INFO(THD *thd, File file_par, uint tot_length, CHARSET_INFO *cs,
+READ_INFO::READ_INFO(THD *thd, File file_par,
+                     const Load_data_param &param,
 		     String &field_term, String &line_start, String &line_term,
 		     String &enclosed_par, int escape, bool get_it_from_net,
 		     bool is_fifo)
-  :file(file_par), fixed_length(tot_length),
+  :Load_data_param(param),
+   file(file_par),
    m_field_term(field_term), m_line_term(line_term), m_line_start(line_start),
    escape_char(escape), found_end_of_line(false), eof(false),
-   error(false), line_cuted(false), found_null(false), read_charset(cs)
+   error(false), line_cuted(false), found_null(false)
 {
   data.set_thread_specific();
   /*
@@ -1459,12 +1333,13 @@ READ_INFO::READ_INFO(THD *thd, File file_par, uint tot_length, CHARSET_INFO *cs,
   enclosed_char= enclosed_par.length() ? (uchar) enclosed_par[0] : INT_MAX;
 
   /* Set of a stack for unget if long terminators */
-  uint length= MY_MAX(cs->mbmaxlen, MY_MAX(m_field_term.length(),
-                                           m_line_term.length())) + 1;
+  uint length= MY_MAX(charset()->mbmaxlen, MY_MAX(m_field_term.length(),
+                                                  m_line_term.length())) + 1;
   set_if_bigger(length,line_start.length());
   stack= stack_pos= (int*) thd->alloc(sizeof(int) * length);
 
-  if (data.reserve(tot_length))
+  DBUG_ASSERT(m_fixed_length < UINT_MAX32);
+  if (data.reserve((size_t) m_fixed_length))
     error=1; /* purecov: inspected */
   else
   {
@@ -1606,7 +1481,7 @@ int READ_INFO::read_field()
   for (;;)
   {
     // Make sure we have enough space for the longest multi-byte character.
-    while (data.length() + read_charset->mbmaxlen <= data.alloced_length())
+    while (data.length() + charset()->mbmaxlen <= data.alloced_length())
     {
       chr = GET;
       if (chr == my_b_EOF)
@@ -1692,7 +1567,7 @@ int READ_INFO::read_field()
 	}
       }
       data.append(chr);
-      if (use_mb(read_charset) && read_mbtail(&data))
+      if (use_mb(charset()) && read_mbtail(&data))
         goto found_eof;
     }
     /*
@@ -1738,7 +1613,7 @@ int READ_INFO::read_fixed_length()
       return 1;
   }
 
-  for (data.length(0); data.length() < fixed_length ; )
+  for (data.length(0); data.length() < m_fixed_length ; )
   {
     if ((chr=GET) == my_b_EOF)
       goto found_eof;
@@ -1791,8 +1666,8 @@ int READ_INFO::next_line()
     if (getbyte(&buf[0]))
       return 1; // EOF
 
-    if (use_mb(read_charset) &&
-        (chlen= my_charlen(read_charset, buf, buf + 1)) != 1)
+    if (use_mb(charset()) &&
+        (chlen= my_charlen(charset(), buf, buf + 1)) != 1)
     {
       uint i;
       for (i= 1; MY_CS_IS_TOOSMALL(chlen); )
@@ -1801,7 +1676,7 @@ int READ_INFO::next_line()
         DBUG_ASSERT(chlen != 1);
         if (getbyte(&buf[i++]))
           return 1; // EOF
-        chlen= my_charlen(read_charset, buf, buf + i);
+        chlen= my_charlen(charset(), buf, buf + i);
       }
 
       /*
@@ -1972,7 +1847,7 @@ int READ_INFO::read_value(int delim, String *val)
     else
     {
       val->append(chr);
-      if (use_mb(read_charset) && read_mbtail(val))
+      if (use_mb(charset()) && read_mbtail(val))
         return my_b_EOF;
     }
   }            
diff --git a/sql/structs.h b/sql/structs.h
index 98eb0f2585d..378b8c387e0 100644
--- a/sql/structs.h
+++ b/sql/structs.h
@@ -629,4 +629,40 @@ public:
 };
 
 
+class Load_data_param
+{
+protected:
+  CHARSET_INFO *m_charset;   // Character set of the file
+  ulonglong m_fixed_length;  // Sum of target field lengths for fixed format
+  bool m_is_fixed_length;
+  bool m_use_blobs;
+public:
+  Load_data_param(CHARSET_INFO *cs, bool is_fixed_length):
+    m_charset(cs),
+    m_fixed_length(0),
+    m_is_fixed_length(is_fixed_length),
+    m_use_blobs(false)
+  { }
+  bool add_outvar_field(THD *thd, const Field *field);
+  bool add_outvar_user_var(THD *thd);
+  CHARSET_INFO *charset() const { return m_charset; }
+  bool is_fixed_length() const { return m_is_fixed_length; }
+  bool use_blobs() const { return m_use_blobs; }
+};
+
+
+class Load_data_outvar
+{
+public:
+  virtual ~Load_data_outvar() {}
+  virtual bool load_data_set_null(THD *thd, const Load_data_param *param)= 0;
+  virtual bool load_data_set_value(THD *thd, const char *pos, uint length,
+                                   const Load_data_param *param)= 0;
+  virtual bool load_data_set_no_data(THD *thd, const Load_data_param *param)= 0;
+  virtual void load_data_print_for_log_event(THD *thd, class String *to) const= 0;
+  virtual bool load_data_add_outvar(THD *thd, Load_data_param *param) const= 0;
+  virtual uint load_data_fixed_length() const= 0;
+};
+
+
 #endif /* STRUCTS_INCLUDED */