more-changes 210.5-mdev21829-unique-interface

7 files changed, 230 insertions, 305 deletions

diff --git a/sql/filesort.cc b/sql/filesort.cc
index 0ee1b85d1e7..4949d63c6d2 100644
--- a/sql/filesort.cc
+++ b/sql/filesort.cc
@@ -3243,185 +3243,3 @@ static uint make_packed_sortkey(Sort_param *param, uchar *to)
   Sort_keys::store_sortkey_length(orig_to, length);
   return length;
 }
-
-
-Variable_sized_keys::Variable_sized_keys(uint size):
-                     packed_rec_ptr(NULL),
-                     sortorder(NULL), sort_keys(NULL),
-                     key_length(size)
-{
-  packed_rec_ptr= (uchar *)my_malloc(PSI_INSTRUMENT_ME,
-                                     size,
-                                     MYF(MY_WME | MY_THREAD_SPECIFIC));
-  tmp_buffer.alloc(size);
-}
-
-
-Variable_sized_keys::~Variable_sized_keys()
-{
-  my_free(packed_rec_ptr);
-}
-
-
-/*
-  @brief
-    Setup the structures that are used when Unique stores packed values
-
-  @param thd                   thread structure
-  @param item                  item of aggregate function
-  @param non_const_args        number of non constant arguments
-  @param arg_count             total number of arguments
-
-  @note
-    This implementation is used by GROUP_CONCAT and COUNT_DISTINCT
-    as it can have more than one arguments in the argument list.
-
-  @retval
-    TRUE  error
-    FALSE setup successful
-*/
-
-bool
-Variable_sized_keys::setup(THD *thd, Item_sum *item,
-                           uint non_const_args, uint arg_count)
-{
-  SORT_FIELD *sort,*pos;
-  if (sortorder)
-    return false;
-  DBUG_ASSERT(sort_keys == NULL);
-  sortorder= (SORT_FIELD*) thd->alloc(sizeof(SORT_FIELD) * non_const_args);
-  pos= sort= sortorder;
-  if (!pos)
-    return true;
-  sort_keys= new Sort_keys(sortorder, non_const_args);
-  if (!sort_keys)
-    return true;
-  sort=pos= sortorder;
-  for (uint i= 0; i < arg_count; i++)
-  {
-    Item *arg= item->get_arg(i);
-    if (arg->const_item())
-      continue;
-
-    if (arg->type() == Item::FIELD_ITEM)
-    {
-      Field *field= ((Item_field*)arg)->field;
-      pos->setup(field, false);
-    }
-    else
-      pos->setup(arg, false);
-    pos++;
-  }
-  return false;
-}
-
-
-/*
-  @brief
-    Setup the structures that are used when Unique stores packed values
-
-  @param thd                   thread structure
-  @param field                 field structure
-
-  @retval
-    TRUE  error
-    FALSE setup successful
-*/
-
-bool Variable_sized_keys::setup(THD *thd, Field *field)
-{
-  SORT_FIELD *sort,*pos;
-  if (sortorder)
-    return false;
-
-  DBUG_ASSERT(sort_keys == NULL);
-  sortorder= (SORT_FIELD*) thd->alloc(sizeof(SORT_FIELD));
-  pos= sort= sortorder;
-  if (!pos)
-    return true;
-  sort_keys= new Sort_keys(sortorder, 1);
-  if (!sort_keys)
-    return true;
-  sort=pos= sortorder;
-  pos->setup(field, false);  // Nulls are always excluded
-
-  return false;
-}
-
-
-/*
-  @brief
-    Compare two packed keys inside the Unique tree
-
-  @param a_ptr             packed sort key
-  @param b_ptr             packed sort key
-
-  @retval
-    >0   key a_ptr greater than b_ptr
-    =0   key a_ptr equal to b_ptr
-    <0   key a_ptr less than b_ptr
-
-*/
-
-int Variable_sized_keys::compare_packed_keys(uchar *a_ptr, uchar *b_ptr)
-{
-  return sort_keys->compare_keys(a_ptr + size_of_length_field,
-                                 b_ptr + size_of_length_field);
-}
-
-
-int Variable_sized_keys::compare_keys_for_single_arg(uchar *a, uchar *b)
-{
-  return sort_keys->compare_keys_for_single_arg(a + size_of_length_field,
-                                                b + size_of_length_field);
-}
-
-
-/*
-  @brief
-    Make a record with packed values for a key
-
-  @retval
-    0         NULL value
-    >0        length of the packed record
-*/
-uint Variable_sized_keys::make_packed_record(bool exclude_nulls)
-{
-  Field *field;
-  SORT_FIELD *sort_field;
-  uint length;
-  uchar *orig_to, *to;
-  orig_to= to= packed_rec_ptr;
-  to+= size_of_length_field;
-
-  for (sort_field=sort_keys->begin() ;
-       sort_field != sort_keys->end() ;
-       sort_field++)
-  {
-    bool maybe_null=0;
-    if ((field=sort_field->field))
-    {
-      // Field
-      length= field->make_packed_sort_key_part(to, sort_field);
-    }
-    else
-    {           // Item
-      Item *item= sort_field->item;
-      length= item->type_handler()->make_packed_sort_key_part(to, item,
-                                                              sort_field,
-                                                              &tmp_buffer);
-    }
-
-    if ((maybe_null= sort_field->maybe_null))
-    {
-      if (exclude_nulls && length == 0)
-        return 0;   // NULL value
-      to++;
-    }
-    to+= length;
-  }
-
-  length= static_cast<int>(to - orig_to);
-  store_packed_length(orig_to, length);
-  return length;
-}
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 8df2b8adce5..972a428978a 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -723,8 +723,8 @@ Aggregator_distinct::composite_packed_key_cmp(void* arg,
                                               uchar* key1, uchar* key2)
 {
   Aggregator_distinct *aggr= (Aggregator_distinct *) arg;
-  DBUG_ASSERT(aggr->variable_sized_keys);
-  return aggr->variable_sized_keys->compare_packed_keys(key1, key2);
+  DBUG_ASSERT(aggr->tree);
+  return aggr->tree->get_descriptor()->compare_keys(key1, key2);
 }
 
 
@@ -746,8 +746,8 @@ int
 Aggregator_distinct::packed_key_cmp_single_arg(void *arg, uchar *key1, uchar *key2)
 {
   Aggregator_distinct *aggr= (Aggregator_distinct *) arg;
-  DBUG_ASSERT(aggr->variable_sized_keys);
-  return aggr->variable_sized_keys->compare_keys_for_single_arg(key1, key2);
+  DBUG_ASSERT(aggr->tree);
+  return aggr->tree->get_descriptor()->compare_keys_for_single_arg(key1, key2);
 }
 
 
@@ -924,10 +924,6 @@ bool Aggregator_distinct::setup(THD *thd)
       {
         compare_key= get_compare_func_for_packed_keys();
         cmp_arg= (void*)this;
-
-        variable_sized_keys= new Variable_sized_keys(tree_key_length);
-        if (variable_sized_keys == NULL)
-          return true;
       }
       DBUG_ASSERT(tree == 0);
 
@@ -1044,10 +1040,10 @@ int Aggregator_distinct::insert_record_to_unique()
   if (tree->is_packed())
   {
     uint packed_length;
-    if ((packed_length= variable_sized_keys->make_packed_record(true)) == 0)
+    if ((packed_length= tree->get_descriptor()->make_packed_record(true)) == 0)
       return -1; // NULL value
     DBUG_ASSERT(packed_length <= tree->get_size());
-    return tree->unique_add(variable_sized_keys->get_packed_rec_ptr());
+    return tree->unique_add(tree->get_descriptor()->get_packed_rec_ptr());
   }
 
   copy_fields(tmp_table_param);
@@ -1920,11 +1916,6 @@ Aggregator_distinct::~Aggregator_distinct()
     delete tmp_table_param;
     tmp_table_param= NULL;
   }
-  if (variable_sized_keys)
-  {
-    delete variable_sized_keys;
-    variable_sized_keys= NULL;
-  }
 }
 
 
@@ -3761,10 +3752,10 @@ int group_concat_packed_key_cmp_with_distinct(void *arg,
 {
   Item_func_group_concat *item_func= (Item_func_group_concat*)arg;
 
-  DBUG_ASSERT(item_func->variable_sized_keys);
+  DBUG_ASSERT(item_func->unique_filter);
   uchar *a= (uchar*)a_ptr;
   uchar *b= (uchar*)b_ptr;
-  return item_func->variable_sized_keys->compare_packed_keys(a, b);
+  return item_func->unique_filter->get_descriptor()->compare_keys(a, b);
 }
 
 
@@ -4040,7 +4031,7 @@ Item_func_group_concat::dump_leaf_variable_sized_key(void *key_arg,
   uint old_length= result->length();
   SORT_FIELD *pos;
 
-  pos= item->variable_sized_keys->get_sortorder();
+  pos= item->unique_filter->get_descriptor()->get_sortorder();
   key_end= key + item->unique_filter->get_full_size();
   key+= Variable_sized_keys_descriptor::size_of_length_field;
 
@@ -4163,8 +4154,7 @@ Item_func_group_concat(THD *thd, Name_resolution_context *context_arg,
    warning_for_row(FALSE),
    force_copy_fields(0), row_limit(NULL),
    offset_limit(NULL), limit_clause(limit_clause),
-   copy_offset_limit(0), copy_row_limit(0), original(0),
-   variable_sized_keys(NULL)
+   copy_offset_limit(0), copy_row_limit(0), original(0)
 {
   Item *item_select;
   Item **arg_ptr;
@@ -4233,8 +4223,7 @@ Item_func_group_concat::Item_func_group_concat(THD *thd,
   force_copy_fields(item->force_copy_fields),
   row_limit(item->row_limit), offset_limit(item->offset_limit),
   limit_clause(item->limit_clause),copy_offset_limit(item->copy_offset_limit),
-  copy_row_limit(item->copy_row_limit), original(item),
-  variable_sized_keys(item->variable_sized_keys)
+  copy_row_limit(item->copy_row_limit), original(item)
 {
   quick_group= item->quick_group;
   result.set_charset(collation.collation);
@@ -4296,11 +4285,6 @@ void Item_func_group_concat::cleanup()
         delete unique_filter;
         unique_filter= NULL;
       }
-      if (variable_sized_keys)
-      {
-        delete variable_sized_keys;
-        variable_sized_keys= NULL;
-      }
     }
     DBUG_ASSERT(tree == 0);
   }
@@ -4695,13 +4679,6 @@ bool Item_func_group_concat::setup(THD *thd)
     tree_len= 0;
   }
 
-  if (allow_packing)
-  {
-    variable_sized_keys= new Variable_sized_keys(tree_key_length);
-    if (variable_sized_keys == NULL)
-      DBUG_RETURN(TRUE); //OOM
-  }
-
   if (distinct)
   {
     unique_filter= get_unique(get_comparator_function_for_distinct(allow_packing),
@@ -4709,10 +4686,10 @@ bool Item_func_group_concat::setup(THD *thd)
                              tree_key_length + get_null_bytes(),
                              ram_limitation(thd), 0, allow_packing);
 
-    if (!unique_filter || (variable_sized_keys &&
-                           variable_sized_keys->setup(thd, this,
-                                                      non_const_items,
-                                                      arg_count_field)))
+    if (!unique_filter ||
+        (unique_filter->get_descriptor()->setup(thd, this,
+                                                non_const_items,
+                                                arg_count_field)))
       DBUG_RETURN(TRUE);
   }
   if ((row_limit && row_limit->cmp_type() != INT_RESULT) ||
@@ -4750,7 +4727,7 @@ String* Item_func_group_concat::val_str(String* str)
       tree_walk(tree, &dump_leaf_key, this, left_root_right);
     else if (distinct) // distinct (and no order by).
       unique_filter->walk(table,
-                          variable_sized_keys ?
+                          unique_filter->is_packed() ?
                           dump_leaf_variable_sized_key :
                           dump_leaf_key, this);
     else if (row_limit && copy_row_limit == (ulonglong)row_limit->val_int())
@@ -4810,7 +4787,7 @@ qsort_cmp2 Item_func_group_concat::get_comparator_function_for_order_by()
 uchar* Item_func_group_concat::get_record_pointer()
 {
   return is_distinct_packed() ?
-         variable_sized_keys->get_packed_rec_ptr() :
+         unique_filter->get_descriptor()->get_packed_rec_ptr() :
          (skip_nulls() ?
           table->record[0] + table->s->null_bytes :
           table->record[0]);
@@ -4845,8 +4822,6 @@ uint Item_func_group_concat::get_null_bytes()
 
 bool Item_func_group_concat::is_distinct_packed()
 {
-  DBUG_ASSERT((variable_sized_keys != NULL) ==
-              (unique_filter && unique_filter->is_packed()));
   return unique_filter && unique_filter->is_packed();
 }
 
@@ -5027,10 +5002,12 @@ int Item_func_group_concat::insert_record_to_unique()
   if (unique_filter->is_packed())
   {
     uint packed_length;
-    if ((packed_length= variable_sized_keys->make_packed_record(skip_nulls())) == 0)
+    if ((packed_length= unique_filter->get_descriptor()->
+                        make_packed_record(skip_nulls())) == 0)
       return -1; // NULL value
     DBUG_ASSERT(packed_length <= unique_filter->get_size());
-    return unique_filter->unique_add(variable_sized_keys->get_packed_rec_ptr());
+    return unique_filter->unique_add(unique_filter->get_descriptor()
+                                     ->get_packed_rec_ptr());
   }
 
   copy_fields(tmp_table_param);
diff --git a/sql/item_sum.h b/sql/item_sum.h
index e7d86137d8c..9bb07bfda52 100644
--- a/sql/item_sum.h
+++ b/sql/item_sum.h
@@ -312,7 +312,6 @@ class Window_spec;
   but still return false from Item_sum::const_item().
 */
 class Unique_impl;
-class Variable_sized_keys;
 
 class Item_sum :public Item_func_or_sum
 {
@@ -682,16 +681,10 @@ class Aggregator_distinct : public Aggregator
   */
   bool use_distinct_values;
 
-  /*
-    Used to store information about variable sized keys
-    @see sql_sort.h for the class definition
-  */
-  Variable_sized_keys *variable_sized_keys;
-
 public:
   Aggregator_distinct (Item_sum *sum) :
     Aggregator(sum), table(NULL), tmp_table_param(NULL), tree(NULL),
-    always_null(false), use_distinct_values(false), variable_sized_keys(NULL) {}
+    always_null(false), use_distinct_values(false) {}
   virtual ~Aggregator_distinct ();
   Aggregator_type Aggrtype() { return DISTINCT_AGGREGATOR; }
 
@@ -1919,8 +1912,6 @@ protected:
   */
   Item_func_group_concat *original;
 
-  Variable_sized_keys *variable_sized_keys;
-
   /*
     Used by Item_func_group_concat and Item_func_json_arrayagg. The latter
     needs null values but the former doesn't.
diff --git a/sql/sql_sort.h b/sql/sql_sort.h
index 342add1445b..b9efe53aa79 100644
--- a/sql/sql_sort.h
+++ b/sql/sql_sort.h
@@ -718,47 +718,5 @@ void reuse_freed_buff(QUEUE *queue, Merge_chunk *reuse, uint key_length);
   <keypart1_value>       : the value for the keypart.
 
 */
-class Variable_sized_keys : public Sql_alloc
-{
-  /*
-    Packed record ptr for a record of the table, the packed value in this
-    record is added to the unique tree
-  */
-  uchar* packed_rec_ptr;
-
-  String tmp_buffer;
-
-  /*
-    Array of SORT_FIELD structure storing the information about the key parts
-    in the sort key of the Unique tree
-    @see Unique::setup()
-  */
-  SORT_FIELD *sortorder;
-
-  /*
-    Structure storing information about usage of keys
-  */
-  Sort_keys *sort_keys;
-
-  uint key_length;
-
-public:
-  Variable_sized_keys(uint size);
-  ~Variable_sized_keys();
-
-  uchar *get_packed_rec_ptr() { return packed_rec_ptr; }
-  Sort_keys *get_keys() { return sort_keys; }
-  SORT_FIELD *get_sortorder() { return sortorder; }
-  bool setup(THD *thd, Item_sum *item, uint non_const_args, uint arg_count);
-  bool setup(THD *thd, Field *field);
-  uint make_packed_record(bool exclude_nulls);
-  int compare_packed_keys(uchar *a, uchar *b);
-  int compare_keys_for_single_arg(uchar *a, uchar *b);
-  static void store_packed_length(uchar *p, uint sz)
-  {
-    int4store(p, sz - size_of_length_field);
-  }
-  static const uint size_of_length_field= 4;
-};
 
 #endif /* SQL_SORT_INCLUDED */
diff --git a/sql/sql_statistics.cc b/sql/sql_statistics.cc
index d6125ce37c7..8dda3b27b8c 100644
--- a/sql/sql_statistics.cc
+++ b/sql/sql_statistics.cc
@@ -1657,7 +1657,6 @@ protected:
 
   ulonglong distincts;
   ulonglong distincts_single_occurence;
-  Variable_sized_keys *variable_size_keys;
 
 public:
   
@@ -1683,15 +1682,12 @@ public:
     table_field= field;
     tree_key_length= 0;
     tree= NULL;
-    variable_size_keys= NULL;
   }
 
   virtual ~Count_distinct_field()
   {
     delete tree;
     tree= NULL;
-    delete variable_size_keys;
-    variable_size_keys= NULL;
   }
 
   /* 
@@ -1720,9 +1716,6 @@ public:
 
       tree_key_length+= Variable_sized_keys_descriptor::size_of_length_field;
       tree_key_length+= MY_TEST(table_field->maybe_null());
-      variable_size_keys= new Variable_sized_keys(tree_key_length);
-      if (!variable_size_keys)
-        return true; // OOM
 
       Descriptor *desc= new Variable_sized_keys_descriptor(tree_key_length);
       if (!desc)
@@ -1732,7 +1725,7 @@ public:
                              max_heap_table_size, 1, desc);
       if (!tree)
         return true; // OOM
-      return variable_size_keys->setup(thd, table_field);
+      return tree->get_descriptor()->setup(thd, table_field);
     }
 
     tree_key_length= table_field->pack_length();
@@ -1758,11 +1751,10 @@ public:
     uint length= tree->get_size();
     if (tree->is_packed())
     {
-      DBUG_ASSERT(variable_size_keys);
-      length= variable_size_keys->make_packed_record(true);
+      length= tree->get_descriptor()->make_packed_record(true);
       DBUG_ASSERT(length != 0);
       DBUG_ASSERT(length <= tree->get_size());
-      return tree->unique_add(variable_size_keys->get_packed_rec_ptr());
+      return tree->unique_add(tree->get_descriptor()->get_packed_rec_ptr());
     }
     return tree->unique_add(table_field->ptr);
   }
@@ -1840,8 +1832,8 @@ int Count_distinct_field::simple_packed_str_key_cmp(void* arg,
                                                     uchar* key1, uchar* key2)
 {
   Count_distinct_field *compare_arg= (Count_distinct_field*)arg;
-  DBUG_ASSERT(compare_arg->variable_size_keys);
-  return compare_arg->variable_size_keys->compare_keys_for_single_arg(key1, key2);
+  DBUG_ASSERT(compare_arg->tree->get_descriptor());
+  return compare_arg->tree->get_descriptor()->compare_keys_for_single_arg(key1, key2);
 }
 
 
diff --git a/sql/uniques.cc b/sql/uniques.cc
index 082bacceff4..3da78f8d5ab 100644
--- a/sql/uniques.cc
+++ b/sql/uniques.cc
@@ -374,6 +374,7 @@ Unique_impl::~Unique_impl()
   close_cached_file(&file);
   delete_tree(&tree, 0);
   delete_dynamic(&file_ptrs);
+  delete m_descriptor;
 }
 
 
@@ -876,9 +877,186 @@ int Unique_impl::write_record_to_file(uchar *key)
 
 
 Variable_sized_keys_descriptor::Variable_sized_keys_descriptor(uint length)
+  :sortorder(NULL), sort_keys(NULL)
 {
   key_length= length;
   flags= (1 << VARIABLE_SIZED_KEYS_WITH_ORIGINAL_VALUES);
+  packed_rec_ptr= (uchar *)my_malloc(PSI_INSTRUMENT_ME,
+                                     length,
+                                     MYF(MY_WME | MY_THREAD_SPECIFIC));
+  tmp_buffer.alloc(length);
+}
+
+
+Variable_sized_keys_descriptor::~Variable_sized_keys_descriptor()
+{
+  my_free(packed_rec_ptr);
+}
+
+
+/*
+  @brief
+    Make a record with packed values for a key
+
+  @retval
+    0         NULL value
+    >0        length of the packed record
+*/
+uint Variable_sized_keys_descriptor::make_packed_record(bool exclude_nulls)
+{
+  Field *field;
+  SORT_FIELD *sort_field;
+  uint length;
+  uchar *orig_to, *to;
+  orig_to= to= packed_rec_ptr;
+  to+= size_of_length_field;
+
+  for (sort_field=sort_keys->begin() ;
+       sort_field != sort_keys->end() ;
+       sort_field++)
+  {
+    bool maybe_null=0;
+    if ((field=sort_field->field))
+    {
+      // Field
+      length= field->make_packed_sort_key_part(to, sort_field);
+    }
+    else
+    {           // Item
+      Item *item= sort_field->item;
+      length= item->type_handler()->make_packed_sort_key_part(to, item,
+                                                              sort_field,
+                                                              &tmp_buffer);
+    }
+
+    if ((maybe_null= sort_field->maybe_null))
+    {
+      if (exclude_nulls && length == 0)
+        return 0;   // NULL value
+      to++;
+    }
+    to+= length;
+  }
+
+  length= static_cast<int>(to - orig_to);
+  store_packed_length(orig_to, length);
+  return length;
+}
+
+
+/*
+  @brief
+    Setup the structures that are used when Unique stores packed values
+
+  @param thd                   thread structure
+  @param item                  item of aggregate function
+  @param non_const_args        number of non constant arguments
+  @param arg_count             total number of arguments
+
+  @note
+    This implementation is used by GROUP_CONCAT and COUNT_DISTINCT
+    as it can have more than one arguments in the argument list.
+
+  @retval
+    TRUE  error
+    FALSE setup successful
+*/
+
+bool
+Variable_sized_keys_descriptor::setup(THD *thd, Item_sum *item,
+                                      uint non_const_args, uint arg_count)
+{
+  SORT_FIELD *sort,*pos;
+  if (sortorder)
+    return false;
+  DBUG_ASSERT(sort_keys == NULL);
+  sortorder= (SORT_FIELD*) thd->alloc(sizeof(SORT_FIELD) * non_const_args);
+  pos= sort= sortorder;
+  if (!pos)
+    return true;
+  sort_keys= new Sort_keys(sortorder, non_const_args);
+  if (!sort_keys)
+    return true;
+  sort=pos= sortorder;
+  for (uint i= 0; i < arg_count; i++)
+  {
+    Item *arg= item->get_arg(i);
+    if (arg->const_item())
+      continue;
+
+    if (arg->type() == Item::FIELD_ITEM)
+    {
+      Field *field= ((Item_field*)arg)->field;
+      pos->setup(field, false);
+    }
+    else
+      pos->setup(arg, false);
+    pos++;
+  }
+  return false;
+}
+
+
+/*
+  @brief
+    Setup the structures that are used when Unique stores packed values
+
+  @param thd                   thread structure
+  @param field                 field structure
+
+  @retval
+    TRUE  error
+    FALSE setup successful
+*/
+
+bool Variable_sized_keys_descriptor::setup(THD *thd, Field *field)
+{
+  SORT_FIELD *sort,*pos;
+  if (sortorder)
+    return false;
+
+  DBUG_ASSERT(sort_keys == NULL);
+  sortorder= (SORT_FIELD*) thd->alloc(sizeof(SORT_FIELD));
+  pos= sort= sortorder;
+  if (!pos)
+    return true;
+  sort_keys= new Sort_keys(sortorder, 1);
+  if (!sort_keys)
+    return true;
+  sort=pos= sortorder;
+  pos->setup(field, false);  // Nulls are always excluded
+
+  return false;
+}
+
+
+/*
+  @brief
+    Compare two packed keys inside the Unique tree
+
+  @param a_ptr             packed sort key
+  @param b_ptr             packed sort key
+
+  @retval
+    >0   key a_ptr greater than b_ptr
+    =0   key a_ptr equal to b_ptr
+    <0   key a_ptr less than b_ptr
+
+*/
+
+int Variable_sized_keys_descriptor::compare_keys(uchar *a_ptr,
+                                                 uchar *b_ptr)
+{
+  return sort_keys->compare_keys(a_ptr + size_of_length_field,
+                                 b_ptr + size_of_length_field);
+}
+
+
+int Variable_sized_keys_descriptor::compare_keys_for_single_arg(uchar *a,
+                                                                uchar *b)
+{
+  return sort_keys->compare_keys_for_single_arg(a + size_of_length_field,
+                                                b + size_of_length_field);
 }
 
 
diff --git a/sql/uniques.h b/sql/uniques.h
index 551c6d5411c..acbc7ef364b 100644
--- a/sql/uniques.h
+++ b/sql/uniques.h
@@ -39,14 +39,15 @@ public:
     return flags & (1 << VARIABLE_SIZED_KEYS_WITH_ORIGINAL_VALUES);
   }
   virtual int compare_keys(uchar *a, uchar *b) = 0;
-  bool setup(THD *thd, Item_sum *item, uint non_const_args, uint arg_count)
-  {
-    return false;
-  }
-  bool setup(THD *thd, Field *field)
-  {
-    return false;
-  }
+  virtual int compare_keys_for_single_arg(uchar *a, uchar *b) = 0;
+  virtual bool setup(THD *thd, Item_sum *item,
+                     uint non_const_args, uint arg_count) { return false; }
+  virtual bool setup(THD *thd, Field *field) { return false; }
+  virtual uchar *get_packed_rec_ptr() { return NULL; }
+  virtual uint make_packed_record(bool exclude_nulls) { return 0; }
+  virtual Sort_keys *get_keys() { return NULL; }
+  SORT_FIELD *get_sortorder() { return NULL; }
+
 };
 
 
@@ -57,6 +58,7 @@ public:
   ~Fixed_sized_keys_descriptor() {}
   uint get_length_of_key(uchar *ptr) override { return key_length; }
   int compare_keys(uchar *a, uchar *b) override { return 0; }
+  int compare_keys_for_single_arg(uchar *a, uchar *b) override { return 0; }
 };
 
 
@@ -68,6 +70,8 @@ class Variable_sized_keys_descriptor : public Descriptor
   */
   uchar* packed_rec_ptr;
 
+  String tmp_buffer;
+
   /*
     Array of SORT_FIELD structure storing the information about the key parts
     in the sort key of the Unique tree
@@ -82,26 +86,33 @@ class Variable_sized_keys_descriptor : public Descriptor
 
 public:
   Variable_sized_keys_descriptor(uint length);
-  ~Variable_sized_keys_descriptor() {}
+  ~Variable_sized_keys_descriptor();
 
   uchar *get_packed_rec_ptr() { return packed_rec_ptr; }
   Sort_keys *get_keys() { return sort_keys; }
   SORT_FIELD *get_sortorder() { return sortorder; }
 
-  // Fill structures like sort_keys, sortorder
-  bool setup() {return false;}
-  uint make_packed_record(bool exclude_nulls) {return 0;}
+  uint make_packed_record(bool exclude_nulls);
   uint get_length_of_key(uchar *ptr) override
   {
     return read_packed_length(ptr);
   }
-  int compare_keys(uchar *a, uchar *b) override { return 0; }
-  int compare_keys_for_single_arg(uchar *a, uchar *b) { return 0;}
+  int compare_keys(uchar *a, uchar *b) override;
+  int compare_keys_for_single_arg(uchar *a, uchar *b);
+
+  // Fill structures like sort_keys, sortorder
+  bool setup(THD *thd, Item_sum *item,
+            uint non_const_args, uint arg_count);
+  bool setup(THD *thd, Field *field);
   // returns the length of the key along with the length bytes for the key
   static uint read_packed_length(uchar *p)
   {
     return size_of_length_field + uint4korr(p);
   }
+  void store_packed_length(uchar *p, uint sz)
+  {
+    int4store(p, sz - size_of_length_field);
+  }
 
   static const uint size_of_length_field= 4;
 };