Hi Varun,

Here's the final review for Percentile Functions. Just 2 minor coding style comments. Rebase on top of current 10.3 and push to a bb-* branch to double check nothing breaks. Make sure that no merge commit happens.

Regards,
Vicențiu

> diff --git a/sql/item_windowfunc.h b/sql/item_windowfunc.h
> index 77cbd556e60..589f7cf5d96 100644
> --- a/sql/item_windowfunc.h
> +++ b/sql/item_windowfunc.h
> @@ -678,6 +687,277 @@ class Item_sum_ntile : public Item_sum_window_with_row_count
>    ulong current_row_count_;
>  };
>  
> +class Item_sum_percentile_disc : public Item_sum_cume_dist,
> +                                 public Type_handler_hybrid_field_type
> +{
> +public:
> +  Item_sum_percentile_disc(THD *thd, Item* arg) : Item_sum_cume_dist(thd, arg),
> +                           Type_handler_hybrid_field_type(&type_handler_longlong),
> +                           value(NULL), val_calculated(FALSE), first_call(TRUE),
> +                           prev_value(0), order_item(NULL){}
> +
> +  double val_real()
> +  {
> +    if (get_row_count() == 0 || get_arg(0)->is_null())
> +    {
> +      null_value= true;
> +      return 0;
> +    }
> +    null_value= false;
> +    return value->val_real();
> +  }
> +
> +  longlong val_int()
> +  {
> +    if (get_row_count() == 0 || get_arg(0)->is_null())
> +    {
> +      null_value= true;
> +      return 0;
> +    }
> +    null_value= false;
> +    return value->val_int();
> +  }
> +
> +  my_decimal* val_decimal(my_decimal* dec)
> +  {
> +    if (get_row_count() == 0 || get_arg(0)->is_null())
> +    {
> +      null_value= true;
> +      return 0;
> +    }
> +    null_value= false;
> +    return value->val_decimal(dec);
> +  }
> +
> +  String* val_str(String *str)
> +  {
> +    if (get_row_count() == 0 || get_arg(0)->is_null())
> +    {
> +      null_value= true;
> +      return 0;
> +    }
> +    null_value= false;
> +    return value->val_str(str);
> +  }
> +
> +  bool add()
> +  {
> +    Item *arg= get_arg(0);
> +    if (arg->is_null())
> +      return false;
> +
> +    if (first_call)
> +    {
> +      prev_value= arg->val_real();
> +      if (prev_value > 1 || prev_value < 0)
> +      {
> +        my_error(ER_ARGUMENT_OUT_OF_RANGE, MYF(0), func_name());
> +        return true;
> +      }
> +      first_call= false;
> +    }
> +
> +    double arg_val= arg->val_real();
> +
> +    if (prev_value != arg_val)
> +    {
> +      my_error(ER_ARGUMENT_NOT_CONSTANT, MYF(0), func_name());
> +      return true;
> +    }
> +
> +    if (val_calculated)
> +      return false;
> +
> +    value->store(order_item);
> +    value->cache_value();
> +    if (value->null_value)
> +       return false;
> +
> +    Item_sum_cume_dist::add();
> +    double val= Item_sum_cume_dist::val_real();
> +
> +    if (val >= prev_value && !val_calculated)
> +      val_calculated= true;
> +    return false;
> +  }
> +
> +  enum Sumfunctype sum_func() const
> +  {
> +    return PERCENTILE_DISC_FUNC;
> +  }
> +
> +  void clear()
> +  {
> +    val_calculated= false;
> +    first_call= true;
> +    value->clear();
> +    Item_sum_cume_dist::clear();
> +  }
> +
> +  const char*func_name() const
> +  {
> +    return "percentile_disc";
> +  }
> +
> +  void update_field() {}
> +  void set_type_handler(Window_spec *window_spec);
> +  const Type_handler *type_handler() const
> +  {return Type_handler_hybrid_field_type::type_handler();}
> +
> +  void fix_length_and_dec()
> +  {
> +    decimals = 10;  // TODO-cvicentiu find out how many decimals the standard
> +                    // requires.
> +  }
> +
> +  Item *get_copy(THD *thd, MEM_ROOT *mem_root)
> +  { return get_item_copy<Item_sum_percentile_disc>(thd, mem_root, this); }
> +  void setup_window_func(THD *thd, Window_spec *window_spec);
> +  void setup_hybrid(THD *thd, Item *item);
> +  bool fix_fields(THD *thd, Item **ref);
> +
> +private:
> +  Item_cache *value;
> +  bool val_calculated;
> +  bool first_call;
> +  double prev_value;
> +  Item *order_item;
> +};
> +
> +class Item_sum_percentile_cont : public Item_sum_cume_dist,
> +                                 public Type_handler_hybrid_field_type
> +{
> +public:
> +  Item_sum_percentile_cont(THD *thd, Item* arg) : Item_sum_cume_dist(thd, arg),
> +                           Type_handler_hybrid_field_type(&type_handler_double),
> +                           floor_value(NULL), ceil_value(NULL), first_call(TRUE),prev_value(0),
> +                           ceil_val_calculated(FALSE), floor_val_calculated(FALSE), order_item(NULL){}
> +
> +  double val_real()
> +  {
> +    if (get_row_count() == 0 || get_arg(0)->is_null())
> +    {
> +      null_value= true;
> +      return 0;
> +    }
> +    null_value= false;
> +    double val= 1 + prev_value * (get_row_count()-1);
> +
> +    /*
> +      Applying the formula to get the value
> +      If (CRN = FRN = RN) then the result is (value of expression from row at RN)
> +      Otherwise the result is
> +      (CRN - RN) * (value of expression for row at FRN) +
> +      (RN - FRN) * (value of expression for row at CRN)
> +    */
> +
> +    if(ceil(val) == floor(val))
> +      return floor_value->val_real();
> +
> +    double ret_val=  ((val - floor(val)) * ceil_value->val_real()) +
> +                  ((ceil(val) - val) * floor_value->val_real());
> +
> +    return ret_val;
> +  }
> +
> +  bool add()
> +  {
> +    Item *arg= get_arg(0);
> +    if (arg->is_null())
> +      return false;
> +
> +    if (first_call)
> +    {
> +      first_call= false;
> +      prev_value= arg->val_real();
> +      if (prev_value > 1 || prev_value < 0)
> +      {
> +        my_error(ER_ARGUMENT_OUT_OF_RANGE, MYF(0), func_name());
> +        return true;
> +      }
> +    }
> +
> +    double arg_val= arg->val_real();
> +    if (prev_value != arg_val)
> +    {
> +      my_error(ER_ARGUMENT_NOT_CONSTANT, MYF(0), func_name());
> +      return true;
> +    }
> +
> +    if (!floor_val_calculated)
> +    {
> +      floor_value->store(order_item);
> +      floor_value->cache_value();
> +      if (floor_value->null_value)
> +       return false;
Add one extra space before return
> +    }
> +    if (floor_val_calculated && !ceil_val_calculated)
> +    {
> +      ceil_value->store(order_item);
> +      ceil_value->cache_value();
> +      if (ceil_value->null_value)
> +       return false;
Add one extra space before return
> +    }
> +
> +    Item_sum_cume_dist::add();
> +    double val= 1 + prev_value * (get_row_count()-1);
> +
> +    if (!floor_val_calculated && get_row_number() == floor(val))
> +       floor_val_calculated= true;
too much indentation here. Delete 2 spaces
> +
> +    if (!ceil_val_calculated && get_row_number() == ceil(val))
> +       ceil_val_calculated= true;
too much indentation here. Delete 2 spaces
> +    return false;
> +  }
> +
> +  enum Sumfunctype sum_func() const
> +  {
> +    return PERCENTILE_CONT_FUNC;
> +  }
> +
> +  void clear()
> +  {
> +    first_call= true;
> +    floor_value->clear();
> +    ceil_value->clear();
> +    floor_val_calculated= false;
> +    ceil_val_calculated= false;
> +    Item_sum_cume_dist::clear();
> +  }
> +
> +  const char*func_name() const
> +  {
> +    return "percentile_cont";
> +  }
> +  void update_field() {}
> +  void set_type_handler(Window_spec *window_spec);
> +  const Type_handler *type_handler() const
> +  {return Type_handler_hybrid_field_type::type_handler();}
> +
> +  void fix_length_and_dec()
> +  {
> +    decimals = 10;  // TODO-cvicentiu find out how many decimals the standard
> +                    // requires.
> +  }
> +
> +  Item *get_copy(THD *thd, MEM_ROOT *mem_root)
> +  { return get_item_copy<Item_sum_percentile_cont>(thd, mem_root, this); }
> +  void setup_window_func(THD *thd, Window_spec *window_spec);
> +  void setup_hybrid(THD *thd, Item *item);
> +  bool fix_fields(THD *thd, Item **ref);
> +
> +private:
> +  Item_cache *floor_value;
> +  Item_cache *ceil_value;
> +  bool first_call;
> +  double prev_value;
> +  bool ceil_val_calculated;
> +  bool floor_val_calculated;
> +  Item *order_item;
> +};
> +
> +
> +
>  
>  class Item_window_func : public Item_func_or_sum
>  {
> diff --git a/sql/lex.h b/sql/lex.h
> index 17dd45f9c0b..fcb44a0f836 100644
> --- a/sql/lex.h
> +++ b/sql/lex.h
> @@ -735,6 +736,7 @@ static SYMBOL sql_functions[] = {
>    { "LAG",              SYM(LAG_SYM)},
>    { "LEAD",             SYM(LEAD_SYM)},
>    { "MAX", SYM(MAX_SYM)},
> +  { "MEDIAN", SYM(MEDIAN_SYM)},
Fix indentation here
>    { "MID", SYM(SUBSTRING)}, /* unireg function */
>    { "MIN", SYM(MIN_SYM)},
>    { "NOW", SYM(NOW_SYM)},
> \ No newline at end of file