9 files changed, 237 insertions, 206 deletions

diff --git a/sql/field.cc b/sql/field.cc
index 07f405ef47c..8f1efbefa38 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -2141,11 +2141,9 @@ Field_str::Field_str(uchar *ptr_arg,uint32 len_arg, uchar *null_ptr_arg,
   :Field(ptr_arg, len_arg, null_ptr_arg, null_bit_arg,
          unireg_check_arg, field_name_arg)
 {
-  field_charset= collation.collation;
+  m_collation= collation;
   if (collation.collation->state & MY_CS_BINSORT)
     flags|=BINARY_FLAG;
-  field_derivation= collation.derivation;
-  field_repertoire= collation.repertoire;
 }
 
 
@@ -2159,7 +2157,7 @@ bool Field_str::test_if_equality_guarantees_uniqueness(const Item *item) const
       SELECT * FROM t1 WHERE varchar_column=DATE'2001-01-01'
     return non-unuque values, e.g. '2001-01-01' and '2001-01-01x'.
   */
-  if (!field_charset->coll->propagate(field_charset, 0, 0) ||
+  if (!field_charset()->coll->propagate(field_charset(), 0, 0) ||
       item->cmp_type() != STRING_RESULT)
     return false;
   /*
@@ -2170,8 +2168,8 @@ bool Field_str::test_if_equality_guarantees_uniqueness(const Item *item) const
       WHERE latin1_bin_column = _latin1'A' COLLATE latin1_swedish_ci
     return non-unique values 'a' and 'A'.
   */
-  DTCollation tmp(field_charset, field_derivation, repertoire());
-  return !tmp.aggregate(item->collation) && tmp.collation == field_charset;
+  DTCollation tmp(dtcollation());
+  return !tmp.aggregate(item->collation) && tmp.collation == field_charset();
 }
 
 
@@ -2453,7 +2451,7 @@ bool Field_null::is_equal(const Column_definition &new_field) const
 {
   DBUG_ASSERT(!compression_method());
   return new_field.type_handler() == type_handler() &&
-         new_field.charset == field_charset &&
+         new_field.charset == field_charset() &&
          new_field.length == max_display_length();
 }
 
@@ -6984,7 +6982,7 @@ Field_longstr::report_if_important_data(const char *pstr, const char *end,
   THD *thd= get_thd();
   if ((pstr < end) && thd->count_cuted_fields > CHECK_FIELD_EXPRESSION)
   {
-    if (test_if_important_data(field_charset, pstr, end))
+    if (test_if_important_data(field_charset(), pstr, end))
     {
       if (thd->abort_on_warning)
         set_warning(ER_DATA_TOO_LONG, 1);
@@ -7015,14 +7013,15 @@ int Field_string::store(const char *from, size_t length,CHARSET_INFO *cs)
 
   rc= well_formed_copy_with_check((char*) ptr, field_length,
                                   cs, from, length,
-                                  field_length / field_charset->mbmaxlen,
+                                  Field_string::char_length(),
                                   false, &copy_length);
 
   /* Append spaces if the string was shorter than the field. */
   if (copy_length < field_length)
-    field_charset->cset->fill(field_charset,(char*) ptr+copy_length,
-                              field_length-copy_length,
-                              field_charset->pad_char);
+    field_charset()->cset->fill(field_charset(),
+                                (char*) ptr + copy_length,
+                                field_length - copy_length,
+                                field_charset()->pad_char);
 
   return rc;
 }
@@ -7032,13 +7031,13 @@ int Field_str::store(longlong nr, bool unsigned_val)
 {
   char buff[64];
   uint  length;
-  length= (uint) (field_charset->cset->longlong10_to_str)(field_charset,
-                                                          buff,
-                                                          sizeof(buff),
-                                                          (unsigned_val ? 10:
-                                                           -10),
-                                                           nr);
-  return store(buff, length, field_charset);
+  length= (uint) (field_charset()->cset->longlong10_to_str)(field_charset(),
+                                                            buff,
+                                                            sizeof(buff),
+                                                            (unsigned_val ? 10:
+                                                             -10),
+                                                             nr);
+  return store(buff, length, field_charset());
 }
 
 
@@ -7054,8 +7053,7 @@ int Field_str::store(double nr)
 {
   DBUG_ASSERT(marked_for_write_or_computed());
   char buff[DOUBLE_TO_STRING_CONVERSION_BUFFER_SIZE];
-  uint local_char_length= MY_MIN(sizeof(buff),
-                                 field_length / field_charset->mbmaxlen);
+  uint local_char_length= MY_MIN(sizeof(buff), Field_str::char_length());
   size_t length= 0;
   my_bool error= (local_char_length == 0);
 
@@ -7078,7 +7076,7 @@ bool Field_string::is_equal(const Column_definition &new_field) const
   DBUG_ASSERT(!compression_method());
   return new_field.type_handler() == type_handler() &&
          new_field.char_length == char_length() &&
-         new_field.charset == field_charset &&
+         new_field.charset == field_charset() &&
          new_field.length == max_display_length();
 }
 
@@ -7164,7 +7162,7 @@ Field_string::Warn_filter_string::Warn_filter_string(const THD *thd,
                                                      const Field_string *field)
   :Warn_filter(!thd->no_errors,
                !thd->no_errors &&
-               field->Field_string::charset() == &my_charset_bin)
+               field->field_charset() == &my_charset_bin)
 { }
 
 
@@ -7200,12 +7198,13 @@ String *Field_string::val_str(String *val_buffer __attribute__((unused)),
   size_t length;
   if (get_thd()->variables.sql_mode &
       MODE_PAD_CHAR_TO_FULL_LENGTH)
-    length= my_charpos(field_charset, ptr, ptr + field_length,
-                       field_length / field_charset->mbmaxlen);
+    length= my_charpos(field_charset(), ptr, ptr + field_length,
+                       Field_string::char_length());
   else
-    length= field_charset->cset->lengthsp(field_charset, (const char*) ptr,
-                                          field_length);
-  val_ptr->set((const char*) ptr, length, field_charset);
+    length= field_charset()->cset->lengthsp(field_charset(),
+                                            (const char*) ptr,
+                                            field_length);
+  val_ptr->set((const char*) ptr, length, field_charset());
   return val_ptr;
 }
 
@@ -7262,11 +7261,11 @@ int Field_string::cmp(const uchar *a_ptr, const uchar *b_ptr) const
 {
   size_t a_len, b_len;
 
-  if (field_charset->mbmaxlen != 1)
+  if (mbmaxlen() != 1)
   {
-    size_t char_len= field_length/field_charset->mbmaxlen;
-    a_len= my_charpos(field_charset, a_ptr, a_ptr + field_length, char_len);
-    b_len= my_charpos(field_charset, b_ptr, b_ptr + field_length, char_len);
+    size_t char_len= Field_string::char_length();
+    a_len= my_charpos(field_charset(), a_ptr, a_ptr + field_length, char_len);
+    b_len= my_charpos(field_charset(), b_ptr, b_ptr + field_length, char_len);
   }
   else
     a_len= b_len= field_length;
@@ -7274,9 +7273,9 @@ int Field_string::cmp(const uchar *a_ptr, const uchar *b_ptr) const
     We have to remove end space to be able to compare multi-byte-characters
     like in latin_de 'ae' and 0xe4
   */
-  return field_charset->coll->strnncollsp(field_charset,
-                                          a_ptr, a_len,
-                                          b_ptr, b_len);
+  return field_charset()->coll->strnncollsp(field_charset(),
+                                            a_ptr, a_len,
+                                            b_ptr, b_len);
 }
 
 
@@ -7285,13 +7284,13 @@ void Field_string::sort_string(uchar *to,uint length)
 #ifdef DBUG_ASSERT_EXISTS
   size_t tmp=
 #endif
-    field_charset->coll->strnxfrm(field_charset,
-                                  to, length,
-                                  char_length() *
-                                  field_charset->strxfrm_multiply,
-                                  ptr, field_length,
-                                  MY_STRXFRM_PAD_WITH_SPACE |
-                                  MY_STRXFRM_PAD_TO_MAXLEN);
+    field_charset()->coll->strnxfrm(field_charset(),
+                                    to, length,
+                                    char_length() *
+                                    field_charset()->strxfrm_multiply,
+                                    ptr, field_length,
+                                    MY_STRXFRM_PAD_WITH_SPACE |
+                                    MY_STRXFRM_PAD_TO_MAXLEN);
   DBUG_ASSERT(tmp == length);
 }
 
@@ -7319,12 +7318,12 @@ void Field_string::sql_type(String &res) const
 uchar *Field_string::pack(uchar *to, const uchar *from, uint max_length)
 {
   size_t length=      MY_MIN(field_length,max_length);
-  size_t local_char_length= max_length/field_charset->mbmaxlen;
+  size_t local_char_length= Field_string::char_length();
   DBUG_PRINT("debug", ("Packing field '%s' - length: %zu ", field_name.str,
                        length));
 
   if (length > local_char_length)
-    local_char_length= my_charpos(field_charset, from, from+length,
+    local_char_length= my_charpos(field_charset(), from, from + length,
                                   local_char_length);
   set_if_smaller(length, local_char_length);
  
@@ -7334,13 +7333,14 @@ uchar *Field_string::pack(uchar *to, const uchar *from, uint max_length)
            (this is for not packing padding adding bytes in BINARY 
            fields).
   */
-  if (field_charset->mbmaxlen == 1)
+  if (mbmaxlen() == 1)
   {
-    while (length && from[length-1] == field_charset->pad_char)
+    while (length && from[length-1] == field_charset()->pad_char)
       length --;
   }
   else
-    length= field_charset->cset->lengthsp(field_charset, (const char*) from, length);
+    length= field_charset()->cset->lengthsp(field_charset(),
+                                            (const char*) from, length);
 
   // Length always stored little-endian
   *to++= (uchar) length;
@@ -7412,7 +7412,10 @@ Field_string::unpack(uchar *to, const uchar *from, const uchar *from_end,
 
   memcpy(to, from, length);
   // Pad the string with the pad character of the fields charset
-  field_charset->cset->fill(field_charset, (char*) to + length, field_length - length, field_charset->pad_char);
+  field_charset()->cset->fill(field_charset(),
+                              (char*) to + length,
+                              field_length - length,
+                              field_charset()->pad_char);
   return from+length;
 }
 
@@ -7475,13 +7478,15 @@ uint Field_string::max_packed_col_length(uint max_length)
 
 uint Field_string::get_key_image(uchar *buff, uint length, imagetype type_arg)
 {
-  size_t bytes = my_charpos(field_charset, (char*) ptr,
-                          (char*) ptr + field_length,
-                          length / field_charset->mbmaxlen);
+  size_t bytes= my_charpos(field_charset(), (char*) ptr,
+                           (char*) ptr + field_length,
+                           length / mbmaxlen());
   memcpy(buff, ptr, bytes);
   if (bytes < length)
-    field_charset->cset->fill(field_charset, (char*) buff + bytes,
-                              length - bytes, field_charset->pad_char);
+    field_charset()->cset->fill(field_charset(),
+                                (char*) buff + bytes,
+                                length - bytes,
+                                field_charset()->pad_char);
   return (uint)bytes;
 }
 
@@ -7557,7 +7562,7 @@ int Field_varstring::store(const char *from,size_t length,CHARSET_INFO *cs)
 
   rc= well_formed_copy_with_check((char*) get_data(), field_length,
                                   cs, from, length,
-                                  field_length / field_charset->mbmaxlen,
+                                  Field_varstring::char_length(),
                                   true, &copy_length);
 
   store_length(copy_length);
@@ -7592,7 +7597,7 @@ String *Field_varstring::val_str(String *val_buffer __attribute__((unused)),
 				 String *val_ptr)
 {
   DBUG_ASSERT(marked_for_read());
-  val_ptr->set((const char*) get_data(), get_length(), field_charset);
+  val_ptr->set((const char*) get_data(), get_length(), field_charset());
   return val_ptr;
 }
 
@@ -7629,13 +7634,9 @@ int Field_varstring::cmp_max(const uchar *a_ptr, const uchar *b_ptr,
   }
   set_if_smaller(a_length, max_len);
   set_if_smaller(b_length, max_len);
-  diff= field_charset->coll->strnncollsp(field_charset,
-                                         a_ptr+
-                                         length_bytes,
-                                         a_length,
-                                         b_ptr+
-                                         length_bytes,
-                                         b_length);
+  diff= field_charset()->coll->strnncollsp(field_charset(),
+                                           a_ptr + length_bytes, a_length,
+                                           b_ptr + length_bytes, b_length);
   return diff;
 }
 
@@ -7648,17 +7649,16 @@ int Field_varstring::cmp_max(const uchar *a_ptr, const uchar *b_ptr,
 int Field_varstring::key_cmp(const uchar *key_ptr, uint max_key_length) const
 {
   size_t length=  length_bytes == 1 ? (uint) *ptr : uint2korr(ptr);
-  size_t local_char_length= max_key_length / field_charset->mbmaxlen;
+  size_t local_char_length= max_key_length / mbmaxlen();
 
-  local_char_length= my_charpos(field_charset, ptr + length_bytes,
-                          ptr + length_bytes + length, local_char_length);
+  local_char_length= my_charpos(field_charset(), ptr + length_bytes,
+                                ptr + length_bytes + length, local_char_length);
   set_if_smaller(length, local_char_length);
-  return field_charset->coll->strnncollsp(field_charset, 
-                                          ptr + length_bytes,
-                                          length,
-                                          key_ptr+
-                                          HA_KEY_BLOB_LENGTH,
-                                          uint2korr(key_ptr));
+  return field_charset()->coll->strnncollsp(field_charset(),
+                                            ptr + length_bytes,
+                                            length,
+                                            key_ptr + HA_KEY_BLOB_LENGTH,
+                                            uint2korr(key_ptr));
 }
 
 
@@ -7672,11 +7672,11 @@ int Field_varstring::key_cmp(const uchar *key_ptr, uint max_key_length) const
 
 int Field_varstring::key_cmp(const uchar *a,const uchar *b) const
 {
-  return field_charset->coll->strnncollsp(field_charset,
-                                          a + HA_KEY_BLOB_LENGTH,
-                                          uint2korr(a),
-                                          b + HA_KEY_BLOB_LENGTH,
-                                          uint2korr(b));
+  return field_charset()->coll->strnncollsp(field_charset(),
+                                            a + HA_KEY_BLOB_LENGTH,
+                                            uint2korr(a),
+                                            b + HA_KEY_BLOB_LENGTH,
+                                            uint2korr(b));
 }
 
 
@@ -7686,7 +7686,7 @@ void Field_varstring::sort_string(uchar *to,uint length)
 
   val_str(&buf, &buf);
 
-  if (field_charset == &my_charset_bin)
+  if (field_charset() == &my_charset_bin)
   {
     /* Store length last in high-byte order to sort longer strings first */
     if (length_bytes == 1)
@@ -7699,11 +7699,13 @@ void Field_varstring::sort_string(uchar *to,uint length)
 #ifdef DBUG_ASSERT_EXISTS
     size_t rc=
 #endif
-  field_charset->coll->strnxfrm(field_charset, to, length,
-                                char_length() * field_charset->strxfrm_multiply,
-                                (const uchar*) buf.ptr(), buf.length(),
-                                MY_STRXFRM_PAD_WITH_SPACE |
-                                MY_STRXFRM_PAD_TO_MAXLEN);
+  field_charset()->coll->strnxfrm(field_charset(),
+                                  to, length,
+                                  char_length() *
+                                  field_charset()->strxfrm_multiply,
+                                  (const uchar*) buf.ptr(), buf.length(),
+                                  MY_STRXFRM_PAD_WITH_SPACE |
+                                  MY_STRXFRM_PAD_TO_MAXLEN);
   DBUG_ASSERT(rc == length);
 }
 
@@ -7844,7 +7846,7 @@ uint Field_varstring::get_key_image(uchar *buff, uint length,
   val_str(&val, &val);
   dbug_tmp_restore_column_map(table->read_set, old_map);
 
-  local_char_length= val.charpos(length / field_charset->mbmaxlen);
+  local_char_length= val.charpos(length / mbmaxlen());
   if (local_char_length < val.length())
     val.length(local_char_length);
   /* Key is always stored with 2 bytes */
@@ -7865,7 +7867,7 @@ uint Field_varstring::get_key_image(uchar *buff, uint length,
 void Field_varstring::set_key_image(const uchar *buff,uint length)
 {
   length= uint2korr(buff);			// Real length is here
-  (void) store((const char*) buff + HA_KEY_BLOB_LENGTH, length, field_charset);
+  (void) store((const char*) buff + HA_KEY_BLOB_LENGTH, length, field_charset());
 }
 
 
@@ -7925,7 +7927,7 @@ bool Field_varstring::is_equal(const Column_definition &new_field) const
          new_field.length == field_length &&
          new_field.char_length == char_length() &&
          !new_field.compression_method() == !compression_method() &&
-         new_field.charset == field_charset;
+         new_field.charset == field_charset();
 }
 
 
@@ -7989,10 +7991,10 @@ int Field_longstr::compress(char *to, uint to_length,
   uint buf_length;
   int rc= 0;
 
-  if (String::needs_conversion_on_storage(length, cs, field_charset) ||
+  if (String::needs_conversion_on_storage(length, cs, field_charset()) ||
       max_length < length)
   {
-    set_if_smaller(max_length, static_cast<ulonglong>(field_charset->mbmaxlen) * length + 1);
+    set_if_smaller(max_length, static_cast<ulonglong>(mbmaxlen()) * length + 1);
     if (!(buf= (char*) my_malloc(max_length, MYF(MY_WME))))
     {
       *out_length= 0;
@@ -8052,7 +8054,7 @@ String *Field_longstr::uncompress(String *val_buffer, String *val_ptr,
     /* Uncompressed data */
     if (!method)
     {
-      val_ptr->set((const char*) from + 1, from_length - 1, field_charset);
+      val_ptr->set((const char*) from + 1, from_length - 1, field_charset());
       return val_ptr;
     }
 
@@ -8061,7 +8063,7 @@ String *Field_longstr::uncompress(String *val_buffer, String *val_ptr,
       if (!compression_methods[method].uncompress(val_buffer, from, from_length,
                                                   field_length))
       {
-        val_buffer->set_charset(field_charset);
+        val_buffer->set_charset(field_charset());
         status_var_increment(get_thd()->status_var.column_decompressions);
         return val_buffer;
       }
@@ -8073,7 +8075,7 @@ String *Field_longstr::uncompress(String *val_buffer, String *val_ptr,
     safer route, let's return a zero string and let the general
     handler catch the error.
   */
-  val_ptr->set("", 0, field_charset);
+  val_ptr->set("", 0, field_charset());
   return val_ptr;
 }
 
@@ -8105,7 +8107,7 @@ double Field_varstring_compressed::val_real(void)
   THD *thd= get_thd();
   String buf;
   val_str(&buf, &buf);
-  return Converter_strntod_with_warn(thd, Warn_filter(thd), field_charset,
+  return Converter_strntod_with_warn(thd, Warn_filter(thd), field_charset(),
                                      buf.ptr(), buf.length()).result();
 }
 
@@ -8116,7 +8118,7 @@ longlong Field_varstring_compressed::val_int(void)
   THD *thd= get_thd();
   String buf;
   val_str(&buf, &buf);
-  return Converter_strntoll_with_warn(thd, Warn_filter(thd), field_charset,
+  return Converter_strntoll_with_warn(thd, Warn_filter(thd), field_charset(),
                                       buf.ptr(), buf.length()).result();
 }
 
@@ -8146,7 +8148,7 @@ int Field_varstring_compressed::cmp_max(const uchar *a_ptr, const uchar *b_ptr,
   if (b.length() > max_len)
     b.length(max_len);
 
-  return sortcmp(&a, &b, field_charset);
+  return sortcmp(&a, &b, field_charset());
 }
 
 
@@ -8191,7 +8193,7 @@ uint32 Field_blob::get_length(const uchar *pos, uint packlength_arg) const
 */
 int Field_blob::copy_value(Field_blob *from)
 {
-  DBUG_ASSERT(field_charset == from->charset());
+  DBUG_ASSERT(field_charset() == from->charset());
   DBUG_ASSERT(!compression_method() == !from->compression_method());
   int rc= 0;
   uint32 length= from->get_length();
@@ -8199,7 +8201,7 @@ int Field_blob::copy_value(Field_blob *from)
   if (packlength < from->packlength)
   {
     set_if_smaller(length, Field_blob::max_data_length());
-    length= (uint32) Well_formed_prefix(field_charset,
+    length= (uint32) Well_formed_prefix(field_charset(),
                                         (const char *) data, length).length();
     rc= report_if_important_data((const char *) data + length,
                                  (const char *) data + from->get_length(),
@@ -8236,7 +8238,7 @@ int Field_blob::store(const char *from,size_t length,CHARSET_INFO *cs)
   if (table && table->blob_storage)    // GROUP_CONCAT with ORDER BY | DISTINCT
   {
     DBUG_ASSERT(!f_is_hex_escape(flags));
-    DBUG_ASSERT(field_charset == cs);
+    DBUG_ASSERT(field_charset() == cs);
     DBUG_ASSERT(length <= max_data_length());
     
     new_length= length;
@@ -8267,7 +8269,7 @@ int Field_blob::store(const char *from,size_t length,CHARSET_INFO *cs)
       If content of the 'from'-address is cached in the 'value'-object
       it is possible that the content needs a character conversion.
     */
-    if (!String::needs_conversion_on_storage(length, cs, field_charset))
+    if (!String::needs_conversion_on_storage(length, cs, field_charset()))
     {
       Field_blob::store_length(length);
       bmove(ptr + packlength, &from, sizeof(char*));
@@ -8278,14 +8280,14 @@ int Field_blob::store(const char *from,size_t length,CHARSET_INFO *cs)
     from= tmpstr.ptr();
   }
 
-  new_length= MY_MIN(max_data_length(), field_charset->mbmaxlen * length);
+  new_length= MY_MIN(max_data_length(), mbmaxlen() * length);
   if (value.alloc(new_length))
     goto oom_error;
   tmp= const_cast<char*>(value.ptr());
 
   if (f_is_hex_escape(flags))
   {
-    copy_length= my_copy_with_hex_escaping(field_charset,
+    copy_length= my_copy_with_hex_escaping(field_charset(),
                                            tmp, new_length,
                                            from, length);
     Field_blob::store_length(copy_length);
@@ -8375,8 +8377,8 @@ my_decimal *Field_blob::val_decimal(my_decimal *decimal_value)
 int Field_blob::cmp(const uchar *a,uint32 a_length, const uchar *b,
 		    uint32 b_length) const
 {
-  return field_charset->coll->strnncollsp(field_charset, 
-                                          a, a_length, b, b_length);
+  return field_charset()->coll->strnncollsp(field_charset(),
+                                            a, a_length, b, b_length);
 }
 
 
@@ -8418,8 +8420,8 @@ uint Field_blob::get_key_image_itRAW(uchar *buff, uint length)
 {
   size_t blob_length= get_length(ptr);
   uchar *blob= get_ptr();
-  size_t local_char_length= length / field_charset->mbmaxlen;
-  local_char_length= my_charpos(field_charset, blob, blob + blob_length,
+  size_t local_char_length= length / mbmaxlen();
+  local_char_length= my_charpos(field_charset(), blob, blob + blob_length,
                           local_char_length);
   set_if_smaller(blob_length, local_char_length);
 
@@ -8442,7 +8444,7 @@ void Field_blob::set_key_image(const uchar *buff,uint length)
 {
   length= uint2korr(buff);
   (void) Field_blob::store((const char*) buff+HA_KEY_BLOB_LENGTH, length,
-                           field_charset);
+                           field_charset());
 }
 
 
@@ -8504,7 +8506,7 @@ int Field_blob::save_field_metadata(uchar *metadata_ptr)
 uint32 Field_blob::sort_length() const
 {
   return (uint32) (get_thd()->variables.max_sort_length + 
-                   (field_charset == &my_charset_bin ? 0 : packlength));
+                   (field_charset() == &my_charset_bin ? 0 : packlength));
 }
 
 
@@ -8513,11 +8515,11 @@ void Field_blob::sort_string(uchar *to,uint length)
   String buf;
 
   val_str(&buf, &buf);
-  if (!buf.length() && field_charset->pad_char == 0)
+  if (!buf.length() && field_charset()->pad_char == 0)
     bzero(to,length);
   else
   {
-    if (field_charset == &my_charset_bin)
+    if (field_charset() == &my_charset_bin)
     {
       /*
         Store length of blob last in blob to shorter blobs before longer blobs
@@ -8529,10 +8531,10 @@ void Field_blob::sort_string(uchar *to,uint length)
 #ifdef DBUG_ASSERT_EXISTS
     size_t rc=
 #endif
-    field_charset->coll->strnxfrm(field_charset, to, length, length,
-                                  (const uchar*) buf.ptr(), buf.length(),
-                                  MY_STRXFRM_PAD_WITH_SPACE |
-                                  MY_STRXFRM_PAD_TO_MAXLEN);
+    field_charset()->coll->strnxfrm(field_charset(), to, length, length,
+                                    (const uchar*) buf.ptr(), buf.length(),
+                                    MY_STRXFRM_PAD_WITH_SPACE |
+                                    MY_STRXFRM_PAD_TO_MAXLEN);
     DBUG_ASSERT(rc == length);
   }
 }
@@ -8663,7 +8665,7 @@ bool Field_blob::is_equal(const Column_definition &new_field) const
   return new_field.type_handler() == type_handler() &&
          !new_field.compression_method() == !compression_method() &&
          new_field.pack_length == pack_length() &&
-         new_field.charset == field_charset;
+         new_field.charset == field_charset();
 }
 
 
@@ -8699,8 +8701,7 @@ int Field_blob_compressed::store(const char *from, size_t length,
   DBUG_ASSERT(marked_for_write_or_computed());
   uint compressed_length;
   uint max_length= max_data_length();
-  uint to_length= (uint) MY_MIN(max_length,
-                                field_charset->mbmaxlen * length + 1);
+  uint to_length= (uint) MY_MIN(max_length, mbmaxlen() * length + 1);
   String tmp(from, length, cs);
   int rc;
 
@@ -8734,7 +8735,7 @@ double Field_blob_compressed::val_real(void)
   THD *thd= get_thd();
   String buf;
   val_str(&buf, &buf);
-  return Converter_strntod_with_warn(thd, Warn_filter(thd), field_charset,
+  return Converter_strntod_with_warn(thd, Warn_filter(thd), field_charset(),
                                      buf.ptr(), buf.length()).result();
 }
 
@@ -8745,7 +8746,7 @@ longlong Field_blob_compressed::val_int(void)
   THD *thd= get_thd();
   String buf;
   val_str(&buf, &buf);
-  return Converter_strntoll_with_warn(thd, Warn_filter(thd), field_charset,
+  return Converter_strntoll_with_warn(thd, Warn_filter(thd), field_charset(),
                                       buf.ptr(), buf.length()).result();
 }
 
@@ -8787,17 +8788,17 @@ int Field_enum::store(const char *from,size_t length,CHARSET_INFO *cs)
   String tmpstr(buff,sizeof(buff), &my_charset_bin);
 
   /* Convert character set if necessary */
-  if (String::needs_conversion_on_storage(length, cs, field_charset))
+  if (String::needs_conversion_on_storage(length, cs, field_charset()))
   { 
     uint dummy_errors;
-    tmpstr.copy(from, length, cs, field_charset, &dummy_errors);
+    tmpstr.copy(from, length, cs, field_charset(), &dummy_errors);
     from= tmpstr.ptr();
     length=  tmpstr.length();
   }
 
   /* Remove end space */
-  length= (uint)field_charset->cset->lengthsp(field_charset, from, length);
-  uint tmp=find_type2(typelib, from, length, field_charset);
+  length= (uint)field_charset()->cset->lengthsp(field_charset(), from, length);
+  uint tmp=find_type2(typelib, from, length, field_charset());
   if (!tmp)
   {
     if (length < 6) // Can't be more than 99999 enums
@@ -8890,11 +8891,11 @@ String *Field_enum::val_str(String *val_buffer __attribute__((unused)),
 {
   uint tmp=(uint) Field_enum::val_int();
   if (!tmp || tmp > typelib->count)
-    val_ptr->set("", 0, field_charset);
+    val_ptr->set("", 0, field_charset());
   else
     val_ptr->set((const char*) typelib->type_names[tmp-1],
 		 typelib->type_lengths[tmp-1],
-		 field_charset);
+		 field_charset());
   return val_ptr;
 }
 
@@ -8973,14 +8974,14 @@ int Field_set::store(const char *from,size_t length,CHARSET_INFO *cs)
   String tmpstr(buff,sizeof(buff), &my_charset_bin);
 
   /* Convert character set if necessary */
-  if (String::needs_conversion_on_storage(length, cs, field_charset))
+  if (String::needs_conversion_on_storage(length, cs, field_charset()))
   { 
     uint dummy_errors;
-    tmpstr.copy(from, length, cs, field_charset, &dummy_errors);
+    tmpstr.copy(from, length, cs, field_charset(), &dummy_errors);
     from= tmpstr.ptr();
     length=  tmpstr.length();
   }
-  ulonglong tmp= find_set(typelib, from, length, field_charset,
+  ulonglong tmp= find_set(typelib, from, length, field_charset(),
                           &not_used, &not_used2, &got_warning);
   if (!tmp && length && length < 22)
   {
@@ -9040,7 +9041,7 @@ String *Field_set::val_str(String *val_buffer,
     return val_buffer;
   }
 
-  val_buffer->set_charset(field_charset);
+  val_buffer->set_charset(field_charset());
   val_buffer->length(0);
 
   while (tmp && bitnr < (uint) typelib->count)
@@ -9051,7 +9052,7 @@ String *Field_set::val_str(String *val_buffer,
 	val_buffer->append(&field_separator, 1, &my_charset_latin1);
       String str(typelib->type_names[bitnr],
 		 typelib->type_lengths[bitnr],
-		 field_charset);
+		 field_charset());
       val_buffer->append(str);
     }
     tmp>>=1;
@@ -9137,7 +9138,7 @@ bool Field_enum::eq_def(const Field *field) const
   if (typelib->count != values->count)
     return FALSE;
 
-  return compare_type_names(field_charset, typelib, values);
+  return compare_type_names(field_charset(), typelib, values);
 }
 
 
@@ -9159,7 +9160,7 @@ bool Field_enum::is_equal(const Column_definition &new_field) const
     type, charset and have the same underlying length.
   */
   if (new_field.type_handler() != type_handler() ||
-      new_field.charset != field_charset ||
+      new_field.charset != field_charset() ||
       new_field.pack_length != pack_length())
     return false;
 
@@ -9172,7 +9173,7 @@ bool Field_enum::is_equal(const Column_definition &new_field) const
     return false;
 
   /* Check whether there are modification before the end. */
-  if (! compare_type_names(field_charset, typelib, new_field.interval))
+  if (! compare_type_names(field_charset(), typelib, new_field.interval))
     return false;
 
   return true;
@@ -9334,6 +9335,14 @@ Field_bit::Field_bit(uchar *ptr_arg, uint32 len_arg, uchar *null_ptr_arg,
 }
 
 
+const DTCollation & Field_bit::dtcollation() const
+{
+  static DTCollation tmp(&my_charset_bin,
+                         DERIVATION_IMPLICIT, MY_REPERTOIRE_UNICODE30);
+  return tmp;
+}
+
+
 void Field_bit::hash(ulong *nr, ulong *nr2)
 {
   if (is_null())
@@ -10660,11 +10669,11 @@ uint32 Field_blob::max_display_length() const
   switch (packlength)
   {
   case 1:
-    return 255 * field_charset->mbmaxlen;
+    return 255 * mbmaxlen();
   case 2:
-    return 65535 * field_charset->mbmaxlen;
+    return 65535 * mbmaxlen();
   case 3:
-    return 16777215 * field_charset->mbmaxlen;
+    return 16777215 * mbmaxlen();
   case 4:
     return (uint32) UINT_MAX32;
   default:
@@ -10947,7 +10956,7 @@ void Field_string::print_key_value(String *out, uint32 length)
 {
   if (charset() == &my_charset_bin)
   {
-    size_t len= field_charset->cset->lengthsp(field_charset, (const char*) ptr, length);
+    size_t len= field_charset()->cset->lengthsp(field_charset(), (const char*) ptr, length);
     print_key_value_binary(out, ptr, static_cast<uint32>(len));
   }
   else
diff --git a/sql/field.h b/sql/field.h
index 18404e5a7bd..634063fe774 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -781,10 +781,6 @@ public:
         const LEX_CSTRING *field_name_arg);
   virtual ~Field() {}
 
-  DTCollation dtcollation() const
-  {
-    return DTCollation(charset(), derivation(), repertoire());
-  }
   virtual Type_std_attributes type_std_attributes() const
   {
     return Type_std_attributes(field_length, decimals(),
@@ -1424,14 +1420,12 @@ public:
   uint fill_cache_field(struct st_cache_field *copy);
   virtual bool get_date(MYSQL_TIME *ltime, date_mode_t fuzzydate);
   virtual const TYPELIB *get_typelib() const { return NULL; }
-  virtual CHARSET_INFO *charset(void) const { return &my_charset_bin; }
+  virtual CHARSET_INFO *charset(void) const= 0;
+  virtual const DTCollation &dtcollation() const= 0;
   virtual CHARSET_INFO *charset_for_protocol(void) const
   { return binary() ? &my_charset_bin : charset(); }
   virtual CHARSET_INFO *sort_charset(void) const { return charset(); }
   virtual bool has_charset(void) const { return FALSE; }
-  virtual enum Derivation derivation(void) const
-  { return DERIVATION_IMPLICIT; }
-  virtual uint repertoire(void) const { return MY_REPERTOIRE_UNICODE30; }
   virtual int set_time() { return 1; }
   bool set_warning(Sql_condition::enum_warning_level, unsigned int code,
                    int cuted_increment, ulong current_row=0) const;
@@ -1826,9 +1820,14 @@ public:
 	    uchar null_bit_arg, utype unireg_check_arg,
 	    const LEX_CSTRING *field_name_arg,
             uint8 dec_arg, bool zero_arg, bool unsigned_arg);
-  enum Derivation derivation(void) const { return DERIVATION_NUMERIC; }
-  uint repertoire(void) const { return MY_REPERTOIRE_NUMERIC; }
-  CHARSET_INFO *charset(void) const { return &my_charset_numeric; }
+  CHARSET_INFO *charset(void) const
+  {
+    return DTCollation_numeric::singleton().collation;
+  }
+  const DTCollation &dtcollation() const
+  {
+    return DTCollation_numeric::singleton();
+  }
   Item *get_equal_const_item(THD *thd, const Context &ctx, Item *const_item)
   {
     return (flags & ZEROFILL_FLAG) ?
@@ -1879,10 +1878,10 @@ public:
 
 class Field_str :public Field {
 protected:
-  // TODO-10.2: Reuse DTCollation instead of these three members
-  CHARSET_INFO *field_charset;
-  enum Derivation field_derivation;
-  uint field_repertoire;
+  DTCollation m_collation;
+  // A short alias for m_collation.collation with non-virtual linkage
+  const CHARSET_INFO *field_charset() const { return m_collation.collation; }
+  uint mbmaxlen() const { return m_collation.collation->mbmaxlen; }
 public:
   bool can_be_substituted_to_equal_item(const Context &ctx,
                                         const Item_equal *item_equal);
@@ -1906,13 +1905,18 @@ public:
   {
     return store(str, length, &my_charset_bin);
   }
-  uint repertoire(void) const { return field_repertoire; }
-  CHARSET_INFO *charset(void) const { return field_charset; }
-  enum Derivation derivation(void) const { return field_derivation; }
-  bool binary() const { return field_charset == &my_charset_bin; }
+  CHARSET_INFO *charset(void) const { return m_collation.collation; }
+  const DTCollation &dtcollation() const
+  {
+    return m_collation;
+  }
+  bool binary() const { return field_charset() == &my_charset_bin; }
   uint32 max_display_length() const { return field_length; }
   uint32 character_octet_length() const { return field_length; }
-  uint32 char_length() const { return field_length / field_charset->mbmaxlen; }
+  uint32 char_length() const
+  {
+    return field_length / mbmaxlen();
+  }
   Information_schema_character_attributes
     information_schema_character_attributes() const
   {
@@ -1961,7 +1965,7 @@ protected:
   {
     String_copier copier;
 
-    *copy_length= copier.well_formed_copy(field_charset, to, to_length,
+    *copy_length= copier.well_formed_copy(field_charset(), to, to_length,
                                           from_cs, from, from_length,
                                           nchars);
 
@@ -2785,9 +2789,14 @@ public:
   bool memcpy_field_possible(const Field *from) const;
   uint32 max_display_length() const { return field_length; }
   bool str_needs_quotes() { return TRUE; }
-  enum Derivation derivation(void) const { return DERIVATION_NUMERIC; }
-  uint repertoire(void) const { return MY_REPERTOIRE_NUMERIC; }
-  CHARSET_INFO *charset(void) const { return &my_charset_numeric; }
+  CHARSET_INFO *charset(void) const
+  {
+    return DTCollation_numeric::singleton().collation;
+  }
+  const DTCollation &dtcollation() const
+  {
+    return DTCollation_numeric::singleton();
+  }
   CHARSET_INFO *sort_charset(void) const { return &my_charset_bin; }
   bool binary() const { return true; }
   bool val_bool() { return val_real() != 0e0; }
@@ -3762,7 +3771,7 @@ public:
   uint32 key_length() const { return (uint32) field_length; }
   uint32 sort_length() const
   {
-    return (uint32) field_length + (field_charset == &my_charset_bin ?
+    return (uint32) field_length + (field_charset() == &my_charset_bin ?
                                     length_bytes : 0);
   }
   Copy_func *get_copy_func(const Field *from) const;
@@ -3854,7 +3863,7 @@ private:
   uint32 character_octet_length() const { return field_length - 1; }
   uint32 char_length() const
   {
-    return (field_length - 1) / field_charset->mbmaxlen;
+    return (field_length - 1) / mbmaxlen();
   }
   int cmp_max(const uchar *a_ptr, const uchar *b_ptr, uint max_len) const;
 
@@ -3992,7 +4001,7 @@ public:
     information_schema_character_attributes() const
   {
     uint32 octets= Field_blob::character_octet_length();
-    uint32 chars= octets / field_charset->mbminlen;
+    uint32 chars= octets / field_charset()->mbminlen;
     return Information_schema_character_attributes(octets, chars);
   }
   void update_data_type_statistics(Data_type_statistics *st) const
@@ -4411,6 +4420,8 @@ public:
   enum_conv_type rpl_conv_type_from(const Conv_source &source,
                                     const Relay_log_info *rli,
                                     const Conv_param &param) const;
+  CHARSET_INFO *charset() const { return &my_charset_bin; }
+  const DTCollation & dtcollation() const;
   Information_schema_numeric_attributes
     information_schema_numeric_attributes() const
   {
diff --git a/sql/item.cc b/sql/item.cc
index b460b01bb8d..0c598fbab9e 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -2060,7 +2060,7 @@ bool Item_name_const::fix_fields(THD *thd, Item **ref)
     return TRUE;
   }
   if (value_item->collation.derivation == DERIVATION_NUMERIC)
-    collation.set_numeric();
+    collation= DTCollation_numeric();
   else
     collation.set(value_item->collation.collation, DERIVATION_IMPLICIT);
   max_length= value_item->max_length;
@@ -3923,7 +3923,7 @@ void Item_param::set_int(longlong i, uint32 max_length_arg)
   DBUG_ASSERT(value.type_handler()->cmp_type() == INT_RESULT);
   value.integer= (longlong) i;
   state= SHORT_DATA_VALUE;
-  collation.set_numeric();
+  collation= DTCollation_numeric();
   max_length= max_length_arg;
   decimals= 0;
   maybe_null= 0;
@@ -3937,7 +3937,7 @@ void Item_param::set_double(double d)
   DBUG_ASSERT(value.type_handler()->cmp_type() == REAL_RESULT);
   value.real= d;
   state= SHORT_DATA_VALUE;
-  collation.set_numeric();
+  collation= DTCollation_numeric();
   max_length= DBL_DIG + 8;
   decimals= NOT_FIXED_DEC;
   maybe_null= 0;
@@ -3968,7 +3968,7 @@ void Item_param::set_decimal(const char *str, ulong length)
   str2my_decimal(E_DEC_FATAL_ERROR, str, &value.m_decimal, &end);
   state= SHORT_DATA_VALUE;
   decimals= value.m_decimal.frac;
-  collation.set_numeric();
+  collation= DTCollation_numeric();
   max_length=
     my_decimal_precision_to_length_no_truncation(value.m_decimal.precision(),
                                                  decimals, unsigned_flag);
@@ -3985,7 +3985,7 @@ void Item_param::set_decimal(const my_decimal *dv, bool unsigned_arg)
   my_decimal2decimal(dv, &value.m_decimal);
 
   decimals= (uint8) value.m_decimal.frac;
-  collation.set_numeric();
+  collation= DTCollation_numeric();
   unsigned_flag= unsigned_arg;
   max_length= my_decimal_precision_to_length(value.m_decimal.intg + decimals,
                                              decimals, unsigned_flag);
@@ -3997,7 +3997,7 @@ void Item_param::set_decimal(const my_decimal *dv, bool unsigned_arg)
 void Item_param::fix_temporal(uint32 max_length_arg, uint decimals_arg)
 {
   state= SHORT_DATA_VALUE;
-  collation.set_numeric();
+  collation= DTCollation_numeric();
   max_length= max_length_arg;
   decimals= decimals_arg;
   maybe_null= 0;
diff --git a/sql/item.h b/sql/item.h
index 14c29fe4e6a..db879e51077 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -3087,7 +3087,7 @@ public:
 class Item_num: public Item_literal
 {
 public:
-  Item_num(THD *thd): Item_literal(thd) { collation.set_numeric(); }
+  Item_num(THD *thd): Item_literal(thd) { collation= DTCollation_numeric(); }
   Item *safe_charset_converter(THD *thd, CHARSET_INFO *tocs);
   bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate)
   {
@@ -4653,14 +4653,14 @@ public:
   Item_temporal_literal(THD *thd, const MYSQL_TIME *ltime)
    :Item_literal(thd)
   {
-    collation.set(&my_charset_numeric, DERIVATION_NUMERIC, MY_REPERTOIRE_ASCII);
+    collation= DTCollation_numeric();
     decimals= 0;
     cached_time= *ltime;
   }
   Item_temporal_literal(THD *thd, const MYSQL_TIME *ltime, uint dec_arg):
     Item_literal(thd)
   {
-    collation.set(&my_charset_numeric, DERIVATION_NUMERIC, MY_REPERTOIRE_ASCII);
+    collation= DTCollation_numeric();
     decimals= dec_arg;
     cached_time= *ltime;
   }
diff --git a/sql/item_func.cc b/sql/item_func.cc
index 24ab48adf4b..eb569aced9b 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -5502,7 +5502,7 @@ bool Item_func_get_system_var::fix_length_and_dec()
     case SHOW_SINT:
     case SHOW_SLONG:
     case SHOW_SLONGLONG:
-      collation.set_numeric();
+      collation= DTCollation_numeric();
       fix_char_length(MY_INT64_NUM_DECIMAL_DIGITS);
       decimals=0;
       break;
@@ -5536,13 +5536,13 @@ bool Item_func_get_system_var::fix_length_and_dec()
       break;
     case SHOW_BOOL:
     case SHOW_MY_BOOL:
-      collation.set_numeric();
+      collation= DTCollation_numeric();
       fix_char_length(1);
       decimals=0;
       break;
     case SHOW_DOUBLE:
       decimals= 6;
-      collation.set_numeric();
+      collation= DTCollation_numeric();
       fix_char_length(DBL_DIG + 6);
       break;
     default:
diff --git a/sql/item_func.h b/sql/item_func.h
index 17f5378910c..2e97611699c 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -404,13 +404,13 @@ public:
 class Item_real_func :public Item_func
 {
 public:
-  Item_real_func(THD *thd): Item_func(thd) { collation.set_numeric(); }
+  Item_real_func(THD *thd): Item_func(thd) { collation= DTCollation_numeric(); }
   Item_real_func(THD *thd, Item *a): Item_func(thd, a)
-  { collation.set_numeric(); }
+  { collation= DTCollation_numeric(); }
   Item_real_func(THD *thd, Item *a, Item *b): Item_func(thd, a, b)
-  { collation.set_numeric(); }
+  { collation= DTCollation_numeric(); }
   Item_real_func(THD *thd, List<Item> &list): Item_func(thd, list)
-  { collation.set_numeric(); }
+  { collation= DTCollation_numeric(); }
   String *val_str(String*str);
   my_decimal *val_decimal(my_decimal *decimal_value);
   longlong val_int()
@@ -721,19 +721,19 @@ public:
 public:
   Item_func_hybrid_field_type(THD *thd):
     Item_hybrid_func(thd)
-  { collation.set_numeric(); }
+  { collation= DTCollation_numeric(); }
   Item_func_hybrid_field_type(THD *thd, Item *a):
     Item_hybrid_func(thd, a)
-  { collation.set_numeric(); }
+  { collation= DTCollation_numeric(); }
   Item_func_hybrid_field_type(THD *thd, Item *a, Item *b):
     Item_hybrid_func(thd, a, b)
-  { collation.set_numeric(); }
+  { collation= DTCollation_numeric(); }
   Item_func_hybrid_field_type(THD *thd, Item *a, Item *b, Item *c):
     Item_hybrid_func(thd, a, b, c)
-  { collation.set_numeric(); }
+  { collation= DTCollation_numeric(); }
   Item_func_hybrid_field_type(THD *thd, List<Item> &list):
     Item_hybrid_func(thd, list)
-  { collation.set_numeric(); }
+  { collation= DTCollation_numeric(); }
 
   double val_real()
   {
@@ -987,20 +987,20 @@ public:
     Min signed   =  -9,223,372,036,854,775,808 = 19 digits, 20 characters
   */
   Item_int_func(THD *thd): Item_func(thd)
-  { collation.set_numeric(); fix_char_length(21); }
+  { collation= DTCollation_numeric(); fix_char_length(21); }
   Item_int_func(THD *thd, Item *a): Item_func(thd, a)
-  { collation.set_numeric(); fix_char_length(21); }
+  { collation= DTCollation_numeric(); fix_char_length(21); }
   Item_int_func(THD *thd, Item *a, Item *b): Item_func(thd, a, b)
-  { collation.set_numeric(); fix_char_length(21); }
+  { collation= DTCollation_numeric(); fix_char_length(21); }
   Item_int_func(THD *thd, Item *a, Item *b, Item *c): Item_func(thd, a, b, c)
-  { collation.set_numeric(); fix_char_length(21); }
+  { collation= DTCollation_numeric(); fix_char_length(21); }
   Item_int_func(THD *thd, Item *a, Item *b, Item *c, Item *d):
     Item_func(thd, a, b, c, d)
-  { collation.set_numeric(); fix_char_length(21); }
+  { collation= DTCollation_numeric(); fix_char_length(21); }
   Item_int_func(THD *thd, List<Item> &list): Item_func(thd, list)
-  { collation.set_numeric(); fix_char_length(21); }
+  { collation= DTCollation_numeric(); fix_char_length(21); }
   Item_int_func(THD *thd, Item_int_func *item) :Item_func(thd, item)
-  { collation.set_numeric(); }
+  { collation= DTCollation_numeric(); }
   double val_real();
   String *val_str(String*str);
   my_decimal *val_decimal(my_decimal *decimal_value)
@@ -1207,7 +1207,7 @@ public:
    :Item_func(thd, a)
   {
     decimals= (uint8) dec;
-    collation.set_numeric();
+    collation= DTCollation_numeric();
     fix_char_length(my_decimal_precision_to_length_no_truncation(len, dec,
                                                                  unsigned_flag));
   }
diff --git a/sql/item_timefunc.h b/sql/item_timefunc.h
index ae65e1fec18..65fd223d6d4 100644
--- a/sql/item_timefunc.h
+++ b/sql/item_timefunc.h
@@ -170,7 +170,7 @@ class Item_func_month :public Item_func
 {
 public:
   Item_func_month(THD *thd, Item *a): Item_func(thd, a)
-  { collation.set_numeric(); }
+  { collation= DTCollation_numeric(); }
   longlong val_int();
   double val_real()
   { DBUG_ASSERT(fixed == 1); return (double) Item_func_month::val_int(); }
@@ -446,7 +446,7 @@ class Item_func_weekday :public Item_func
   bool odbc_type;
 public:
   Item_func_weekday(THD *thd, Item *a, bool type_arg):
-    Item_func(thd, a), odbc_type(type_arg) { collation.set_numeric(); }
+    Item_func(thd, a), odbc_type(type_arg) { collation= DTCollation_numeric(); }
   longlong val_int();
   double val_real() { DBUG_ASSERT(fixed == 1); return (double) val_int(); }
   String *val_str(String *str)
diff --git a/sql/sql_type.cc b/sql/sql_type.cc
index 103cd255b94..b618622b531 100644
--- a/sql/sql_type.cc
+++ b/sql/sql_type.cc
@@ -24,6 +24,14 @@
 #include "log.h"
 #include "tztime.h"
 
+
+const DTCollation &DTCollation_numeric::singleton()
+{
+  static const DTCollation_numeric tmp;
+  return tmp;
+}
+
+
 Type_handler_row         type_handler_row;
 
 Type_handler_null        type_handler_null;
diff --git a/sql/sql_type.h b/sql/sql_type.h
index 6eeca58df01..8f1d51b1aab 100644
--- a/sql/sql_type.h
+++ b/sql/sql_type.h
@@ -2706,9 +2706,7 @@ public:
   { }
   void set(const DTCollation &dt)
   {
-    collation= dt.collation;
-    derivation= dt.derivation;
-    repertoire= dt.repertoire;
+    *this= dt;
   }
   void set(CHARSET_INFO *collation_arg, Derivation derivation_arg)
   {
@@ -2724,12 +2722,6 @@ public:
     derivation= derivation_arg;
     repertoire= repertoire_arg;
   }
-  void set_numeric()
-  {
-    collation= &my_charset_numeric;
-    derivation= DERIVATION_NUMERIC;
-    repertoire= MY_REPERTOIRE_NUMERIC;
-  }
   void set(CHARSET_INFO *collation_arg)
   {
     collation= collation_arg;
@@ -2763,6 +2755,17 @@ public:
 };
 
 
+class DTCollation_numeric: public DTCollation
+{
+public:
+  DTCollation_numeric()
+   :DTCollation(charset_info(), DERIVATION_NUMERIC, MY_REPERTOIRE_NUMERIC)
+  { }
+  static const CHARSET_INFO *charset_info() { return &my_charset_numeric; }
+  static const DTCollation & singleton();
+};
+
+
 static inline uint32
 char_to_byte_length_safe(size_t char_length_arg, uint32 mbmaxlen_arg)
 {
@@ -2840,7 +2843,7 @@ public:
   }
   void fix_attributes_temporal_not_fixed_dec(uint int_part_length, uint dec)
   {
-    collation.set_numeric();
+    collation= DTCollation_numeric();
     unsigned_flag= 0;
     fix_char_length_temporal_not_fixed_dec(int_part_length, dec);
   }
@@ -2854,7 +2857,7 @@ public:
   }
   void fix_attributes_temporal(uint int_part_length, uint dec)
   {
-    collation.set_numeric();
+    collation= DTCollation_numeric();
     unsigned_flag= 0;
     decimals= MY_MIN(dec, TIME_SECOND_PART_DIGITS);
     max_length= decimals + int_part_length + (dec ? 1 : 0);
@@ -2881,18 +2884,18 @@ public:
 
   void aggregate_attributes_int(Item **items, uint nitems)
   {
-    collation.set_numeric();
+    collation= DTCollation_numeric();
     count_only_length(items, nitems);
     decimals= 0;
   }
   void aggregate_attributes_real(Item **items, uint nitems)
   {
-    collation.set_numeric();
+    collation= DTCollation_numeric();
     count_real_length(items, nitems);
   }
   void aggregate_attributes_decimal(Item **items, uint nitems)
   {
-    collation.set_numeric();
+    collation= DTCollation_numeric();
     count_decimal_length(items, nitems);
   }
   bool aggregate_attributes_string(const char *func_name,