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Diffstat (limited to '')
| -rw-r--r-- | sql/item_windowfunc.cc | 575 |
1 files changed, 575 insertions, 0 deletions
diff --git a/sql/item_windowfunc.cc b/sql/item_windowfunc.cc new file mode 100644 index 00000000..24c2ef5a --- /dev/null +++ b/sql/item_windowfunc.cc @@ -0,0 +1,575 @@ +/* + Copyright (c) 2016, 2020, 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); + + if (!thd->lex->current_select || + (thd->lex->current_select->context_analysis_place != SELECT_LIST && + thd->lex->current_select->context_analysis_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; + + if (fix_length_and_dec()) + return TRUE; + + 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() +{ + switch (window_func()->sum_func()) { + case Item_sum::PERCENTILE_CONT_FUNC: + { + 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; + } + return false; + } + case Item_sum::PERCENTILE_DISC_FUNC: + { + Item *src_item= window_spec->order_list->first->item[0]; + Item_sum_percentile_disc *func= + static_cast<Item_sum_percentile_disc*>(window_func()); + func->set_handler(src_item->type_handler()); + func->Type_std_attributes::set(src_item); + Type_std_attributes::set(src_item); + return false; + } + default: + break; + } + 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++) + { + if (args[i]->fix_fields_if_needed_for_scalar(thd, &args[i])) + return TRUE; + with_window_func|= args[i]->with_window_func; + } + + for (uint i= 0; i < arg_count && !m_with_subquery; i++) + m_with_subquery|= args[i]->with_subquery(); + + if (fix_length_and_dec()) + return true; + + setup_hybrid(thd, args[0]); + result_field=0; + + 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::fix_length_and_dec() +{ + maybe_null= null_value= true; + return args[0]->type_handler()->Item_sum_hybrid_fix_length_and_dec(this); +} + + +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; +} + +bool Item_sum_hybrid_simple::val_native(THD *thd, Native *to) +{ + DBUG_ASSERT(fixed == 1); + if (null_value) + return true; + return val_native_from_item(thd, value, to); +} + +bool Item_sum_hybrid_simple::get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) +{ + DBUG_ASSERT(fixed == 1); + if (null_value) + return true; + bool retval= value->get_date(thd, ltime, fuzzydate); + if ((null_value= value->null_value)) + DBUG_ASSERT(retval == true); + return retval; +} + +Field *Item_sum_hybrid_simple::create_tmp_field(MEM_ROOT *root, + 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: + { + VDec arg_dec(args[0]); + + if (maybe_null) + { + if (arg_dec.is_null()) + 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() + */ + result_field->store_decimal(arg_dec.ptr_or(&decimal_zero)); + 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) +{ + if (only_single_element_order_list()) + { + print_for_percentile_functions(str, query_type); + return; + } + window_func()->print(str, query_type); + str->append(" over "); + if (!window_spec) + str->append(window_name); + else + window_spec->print(str, query_type); +} +void Item_window_func::print_for_percentile_functions(String *str, enum_query_type query_type) +{ + window_func()->print(str, query_type); + str->append(" within group "); + str->append('('); + window_spec->print_order(str,query_type); + str->append(')'); + str->append(" over "); + str->append('('); + window_spec->print_partition(str,query_type); + str->append(')'); +} |