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/*
Copyright (c) 2016,2017 MariaDB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#include "mariadb.h"
#include "item_windowfunc.h"
#include "sql_select.h" // test if group changed
bool
Item_window_func::resolve_window_name(THD *thd)
{
if (window_spec)
{
/* The window name has been already resolved */
return false;
}
DBUG_ASSERT(window_name != NULL && window_spec == NULL);
const char *ref_name= window_name->str;
/* !TODO: Add the code to resolve ref_name in outer queries */
/*
First look for the deinition of the window with 'window_name'
in the current select
*/
List<Window_spec> curr_window_specs=
List<Window_spec> (thd->lex->current_select->window_specs);
List_iterator_fast<Window_spec> it(curr_window_specs);
Window_spec *win_spec;
while((win_spec= it++))
{
const char *win_spec_name= win_spec->name();
if (win_spec_name &&
my_strcasecmp(system_charset_info, ref_name, win_spec_name) == 0)
{
window_spec= win_spec;
break;
}
}
if (!window_spec)
{
my_error(ER_WRONG_WINDOW_SPEC_NAME, MYF(0), ref_name);
return true;
}
return false;
}
void
Item_window_func::update_used_tables()
{
used_tables_cache= 0;
window_func()->update_used_tables();
used_tables_cache|= window_func()->used_tables();
for (ORDER *ord= window_spec->partition_list->first; ord; ord=ord->next)
{
Item *item= *ord->item;
item->update_used_tables();
used_tables_cache|= item->used_tables();
}
for (ORDER *ord= window_spec->order_list->first; ord; ord=ord->next)
{
Item *item= *ord->item;
item->update_used_tables();
used_tables_cache|= item->used_tables();
}
}
bool
Item_window_func::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
enum_parsing_place place= thd->lex->current_select->context_analysis_place;
if (!(place == SELECT_LIST || place == IN_ORDER_BY))
{
my_error(ER_WRONG_PLACEMENT_OF_WINDOW_FUNCTION, MYF(0));
return true;
}
if (window_name && resolve_window_name(thd))
return true;
if (window_spec->window_frame && is_frame_prohibited())
{
my_error(ER_NOT_ALLOWED_WINDOW_FRAME, MYF(0), window_func()->func_name());
return true;
}
if (window_spec->order_list->elements == 0 && is_order_list_mandatory())
{
my_error(ER_NO_ORDER_LIST_IN_WINDOW_SPEC, MYF(0), window_func()->func_name());
return true;
}
/*
TODO: why the last parameter is 'ref' in this call? What if window_func
decides to substitute itself for something else and does *ref=.... ?
This will substitute *this (an Item_window_func object) with Item_sum
object. Is this the intent?
*/
if (window_func()->fix_fields(thd, ref))
return true;
const_item_cache= false;
with_window_func= true;
with_sum_func= false;
fix_length_and_dec();
max_length= window_func()->max_length;
maybe_null= window_func()->maybe_null;
fixed= 1;
set_phase_to_initial();
return false;
}
/*
@detail
Window function evaluates its arguments when it is scanning the temporary
table in partition/order-by order. That is, arguments should be read from
the temporary table, not from the original base columns.
In order for this to work, we need to call "split_sum_func" for each
argument. The effect of the call is:
1. the argument is added into ref_pointer_array. This will cause the
argument to be saved in the temp.table
2. argument item is replaced with an Item_ref object. this object refers
the argument through the ref_pointer_array.
then, change_to_use_tmp_fields() will replace ref_pointer_array with an
array that points to the temp.table fields.
This way, when window_func attempts to evaluate its arguments, it will use
Item_ref objects which will read data from the temp.table.
Note: Before window functions, aggregate functions never needed to do such
transformations on their arguments. This is because grouping operation
does not need to read from the temp.table.
(Q: what happens when we first sort and then do grouping in a
group-after-group mode? dont group by items read from temp.table, then?)
*/
void Item_window_func::split_sum_func(THD *thd, Ref_ptr_array ref_pointer_array,
List<Item> &fields, uint flags)
{
for (uint i=0; i < window_func()->argument_count(); i++)
{
Item **p_item= &window_func()->arguments()[i];
(*p_item)->split_sum_func2(thd, ref_pointer_array, fields, p_item, flags);
}
window_func()->setup_caches(thd);
}
bool Item_window_func::check_result_type_of_order_item()
{
if (only_single_element_order_list())
{
Item_result rtype= window_spec->order_list->first->item[0]->cmp_type();
// TODO (varun) : support date type in percentile_cont function
if (rtype != REAL_RESULT && rtype != INT_RESULT &&
rtype != DECIMAL_RESULT && rtype != TIME_RESULT)
{
my_error(ER_WRONG_TYPE_FOR_PERCENTILE_FUNC, MYF(0), window_func()->func_name());
return TRUE;
}
setting_handler_for_percentile_functions(rtype);
}
return FALSE;
}
/*
This must be called before attempting to compute the window function values.
@detail
If we attempt to do it in fix_fields(), partition_fields will refer
to the original window function arguments.
We need it to refer to temp.table columns.
*/
void Item_sum_rank::setup_window_func(THD *thd, Window_spec *window_spec)
{
/* TODO: move this into Item_window_func? */
peer_tracker = new Group_bound_tracker(thd, window_spec->order_list);
peer_tracker->init();
clear();
}
void Item_sum_dense_rank::setup_window_func(THD *thd, Window_spec *window_spec)
{
/* TODO: consider moving this && Item_sum_rank's implementation */
peer_tracker = new Group_bound_tracker(thd, window_spec->order_list);
peer_tracker->init();
clear();
}
void Item_sum_percentile_disc::setup_window_func(THD *thd, Window_spec *window_spec)
{
order_item= window_spec->order_list->first->item[0];
if (!(value= order_item->get_cache(thd)))
return;
value->setup(thd, order_item);
value->store(order_item);
}
void Item_sum_percentile_cont::setup_window_func(THD *thd, Window_spec *window_spec)
{
order_item= window_spec->order_list->first->item[0];
/* TODO(varun): need to discuss and finalise what type should we
return for percentile cont functions
*/
if (!(ceil_value= order_item->get_cache(thd)))
return;
ceil_value->setup(thd, order_item);
ceil_value->store(order_item);
if (!(floor_value= order_item->get_cache(thd)))
return;
floor_value->setup(thd, order_item);
floor_value->store(order_item);
}
bool Item_sum_percentile_cont::fix_fields(THD *thd, Item **ref)
{
bool res;
res= Item_sum_num::fix_fields(thd, ref);
if (res)
return res;
switch(args[0]->cmp_type())
{
case DECIMAL_RESULT:
case REAL_RESULT:
case INT_RESULT:
break;
default:
my_error(ER_WRONG_TYPE_OF_ARGUMENT, MYF(0), func_name());
return TRUE;
}
return res;
}
bool Item_sum_percentile_disc::fix_fields(THD *thd, Item **ref)
{
bool res;
res= Item_sum_num::fix_fields(thd, ref);
if (res)
return res;
switch(args[0]->cmp_type())
{
case DECIMAL_RESULT:
case REAL_RESULT:
case INT_RESULT:
break;
default:
my_error(ER_WRONG_TYPE_OF_ARGUMENT, MYF(0), func_name());
return TRUE;
}
return res;
}
bool Item_sum_dense_rank::add()
{
if (peer_tracker->check_if_next_group() || first_add)
{
first_add= false;
dense_rank++;
}
return false;
}
bool Item_sum_rank::add()
{
row_number++;
if (peer_tracker->check_if_next_group())
{
/* Row value changed */
cur_rank= row_number;
}
return false;
}
bool Item_sum_percent_rank::add()
{
row_number++;
if (peer_tracker->check_if_next_group())
{
/* Row value changed. */
cur_rank= row_number;
}
return false;
}
void Item_sum_percent_rank::setup_window_func(THD *thd, Window_spec *window_spec)
{
/* TODO: move this into Item_window_func? */
peer_tracker = new Group_bound_tracker(thd, window_spec->order_list);
peer_tracker->init();
clear();
}
bool Item_sum_hybrid_simple::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
if (init_sum_func_check(thd))
return TRUE;
for (uint i= 0; i < arg_count; i++)
{
Item *item= args[i];
// 'item' can be changed during fix_fields
if ((!item->fixed && item->fix_fields(thd, args)) ||
(item= args[i])->check_cols(1))
return TRUE;
}
Type_std_attributes::set(args[0]);
for (uint i= 0; i < arg_count && !with_subselect; i++)
with_subselect= with_subselect || args[i]->with_subselect;
Item *item2= args[0]->real_item();
if (item2->type() == Item::FIELD_ITEM)
set_handler(item2->type_handler());
else if (args[0]->cmp_type() == TIME_RESULT)
set_handler(item2->type_handler());
else
set_handler_by_result_type(item2->result_type(),
max_length, collation.collation);
switch (result_type()) {
case INT_RESULT:
case DECIMAL_RESULT:
case STRING_RESULT:
break;
case REAL_RESULT:
max_length= float_length(decimals);
break;
case ROW_RESULT:
case TIME_RESULT:
DBUG_ASSERT(0); // XXX(cvicentiu) Should this never happen?
return TRUE;
};
setup_hybrid(thd, args[0]);
/* MIN/MAX can return NULL for empty set indepedent of the used column */
maybe_null= 1;
result_field=0;
null_value=1;
fix_length_and_dec();
if (check_sum_func(thd, ref))
return TRUE;
for (uint i= 0; i < arg_count; i++)
{
orig_args[i]= args[i];
}
fixed= 1;
return FALSE;
}
bool Item_sum_hybrid_simple::add()
{
value->store(args[0]);
value->cache_value();
null_value= value->null_value;
return false;
}
void Item_sum_hybrid_simple::setup_hybrid(THD *thd, Item *item)
{
if (!(value= item->get_cache(thd)))
return;
value->setup(thd, item);
value->store(item);
if (!item->const_item())
value->set_used_tables(RAND_TABLE_BIT);
collation.set(item->collation);
}
double Item_sum_hybrid_simple::val_real()
{
DBUG_ASSERT(fixed == 1);
if (null_value)
return 0.0;
double retval= value->val_real();
if ((null_value= value->null_value))
DBUG_ASSERT(retval == 0.0);
return retval;
}
longlong Item_sum_hybrid_simple::val_int()
{
DBUG_ASSERT(fixed == 1);
if (null_value)
return 0;
longlong retval= value->val_int();
if ((null_value= value->null_value))
DBUG_ASSERT(retval == 0);
return retval;
}
my_decimal *Item_sum_hybrid_simple::val_decimal(my_decimal *val)
{
DBUG_ASSERT(fixed == 1);
if (null_value)
return 0;
my_decimal *retval= value->val_decimal(val);
if ((null_value= value->null_value))
DBUG_ASSERT(retval == NULL);
return retval;
}
String *
Item_sum_hybrid_simple::val_str(String *str)
{
DBUG_ASSERT(fixed == 1);
if (null_value)
return 0;
String *retval= value->val_str(str);
if ((null_value= value->null_value))
DBUG_ASSERT(retval == NULL);
return retval;
}
Field *Item_sum_hybrid_simple::create_tmp_field(bool group, TABLE *table)
{
DBUG_ASSERT(0);
return NULL;
}
void Item_sum_hybrid_simple::reset_field()
{
switch(result_type()) {
case STRING_RESULT:
{
char buff[MAX_FIELD_WIDTH];
String tmp(buff,sizeof(buff),result_field->charset()),*res;
res=args[0]->val_str(&tmp);
if (args[0]->null_value)
{
result_field->set_null();
result_field->reset();
}
else
{
result_field->set_notnull();
result_field->store(res->ptr(),res->length(),tmp.charset());
}
break;
}
case INT_RESULT:
{
longlong nr=args[0]->val_int();
if (maybe_null)
{
if (args[0]->null_value)
{
nr=0;
result_field->set_null();
}
else
result_field->set_notnull();
}
result_field->store(nr, unsigned_flag);
break;
}
case REAL_RESULT:
{
double nr= args[0]->val_real();
if (maybe_null)
{
if (args[0]->null_value)
{
nr=0.0;
result_field->set_null();
}
else
result_field->set_notnull();
}
result_field->store(nr);
break;
}
case DECIMAL_RESULT:
{
my_decimal value_buff, *arg_dec= args[0]->val_decimal(&value_buff);
if (maybe_null)
{
if (args[0]->null_value)
result_field->set_null();
else
result_field->set_notnull();
}
/*
We must store zero in the field as we will use the field value in
add()
*/
if (!arg_dec) // Null
arg_dec= &decimal_zero;
result_field->store_decimal(arg_dec);
break;
}
case ROW_RESULT:
case TIME_RESULT:
DBUG_ASSERT(0);
}
}
void Item_sum_hybrid_simple::update_field()
{
DBUG_ASSERT(0);
}
void Item_window_func::print(String *str, enum_query_type query_type)
{
window_func()->print(str, query_type);
str->append(" over ");
window_spec->print(str, query_type);
}
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