Backport of:

3723 oystein.grovlen@sun.com   2009-11-23
Bug#46548 (addendum)
Remove KEY::extra_length.  It is not in use.

sql/structs.h

@@ -75,7 +75,6 @@ typedef struct st_key {
   uint	key_length;			/* Tot length of key */
   ulong flags;                          /* dupp key and pack flags */
   uint	key_parts;			/* How many key_parts */
-  uint  extra_length;
   uint	usable_key_parts;		/* Should normally be = key_parts */
   uint  block_size;
   uint  name_length;

sql/table.cc

@@ -1493,7 +1493,6 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
           key_part->null_bit= field->null_bit;
           key_part->store_length+=HA_KEY_NULL_LENGTH;
           keyinfo->flags|=HA_NULL_PART_KEY;
-          keyinfo->extra_length+= HA_KEY_NULL_LENGTH;
           keyinfo->key_length+= HA_KEY_NULL_LENGTH;
         }
         if (field->type() == MYSQL_TYPE_BLOB ||
@@ -1505,7 +1504,6 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
             key_part->key_part_flag|= HA_BLOB_PART;
           else
             key_part->key_part_flag|= HA_VAR_LENGTH_PART;
-          keyinfo->extra_length+=HA_KEY_BLOB_LENGTH;
           key_part->store_length+=HA_KEY_BLOB_LENGTH;
           keyinfo->key_length+= HA_KEY_BLOB_LENGTH;
         }