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240 lines
7.2 KiB
240 lines
7.2 KiB
/* Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License, version 2.0, for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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/**
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@file
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@brief
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Buffers to save and compare item values
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*/
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#include <stddef.h>
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#include <algorithm>
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#include "my_alloc.h"
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#include "my_dbug.h"
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#include "my_inttypes.h"
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#include "mysql/udf_registration_types.h"
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#include "sql/current_thd.h" // current_thd
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#include "sql/item.h" // Cached_item, ...
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#include "sql/json_dom.h" // Json_wrapper
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#include "sql/my_decimal.h"
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#include "sql/sql_class.h" // THD
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#include "sql/system_variables.h"
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#include "sql/thr_malloc.h"
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#include "sql_string.h"
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#include "template_utils.h"
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using std::max;
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using std::min;
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/**
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Create right type of Cached_item for an item.
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*/
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Cached_item *new_Cached_item(THD *thd, Item *item) {
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switch (item->result_type()) {
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case STRING_RESULT:
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if (item->is_temporal())
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return new (thd->mem_root) Cached_item_temporal(item);
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if (item->data_type() == MYSQL_TYPE_JSON)
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return new (thd->mem_root) Cached_item_json(item);
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return new (thd->mem_root) Cached_item_str(thd, item);
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case INT_RESULT:
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return new (thd->mem_root) Cached_item_int(item);
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case REAL_RESULT:
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return new (thd->mem_root) Cached_item_real(item);
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case DECIMAL_RESULT:
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return new (thd->mem_root) Cached_item_decimal(item);
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case ROW_RESULT:
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default:
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DBUG_ASSERT(0);
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return 0;
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}
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}
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Cached_item::~Cached_item() {}
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/**
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Compare with old value and replace value with new value.
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@return
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Return true if values have changed
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*/
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Cached_item_str::Cached_item_str(THD *thd, Item *arg)
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: Cached_item(arg),
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value_max_length(
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min<uint32>(arg->max_length, thd->variables.max_sort_length)),
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value(value_max_length) {}
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bool Cached_item_str::cmp(void) {
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String *res;
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bool tmp;
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DBUG_TRACE;
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DBUG_ASSERT(!item->is_temporal());
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DBUG_ASSERT(item->data_type() != MYSQL_TYPE_JSON);
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if ((res = item->val_str(&tmp_value)))
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res->length(min(res->length(), static_cast<size_t>(value_max_length)));
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DBUG_PRINT("info", ("old: %s, new: %s", value.c_ptr_safe(),
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res ? res->c_ptr_safe() : ""));
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if (null_value != item->null_value) {
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if ((null_value = item->null_value)) return true; // New value was null
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tmp = true;
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} else if (null_value)
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return 0; // new and old value was null
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else
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tmp = sortcmp(&value, res, item->collation.collation) != 0;
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if (tmp) value.copy(*res); // Remember for next cmp
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return tmp;
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}
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Cached_item_str::~Cached_item_str() {
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item = 0; // Safety
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}
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Cached_item_json::Cached_item_json(Item *item_arg)
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: Cached_item(item_arg), m_value(new (*THR_MALLOC) Json_wrapper()) {}
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Cached_item_json::~Cached_item_json() { destroy(m_value); }
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/**
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Compare the new JSON value in member 'item' with the previous value.
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@retval true if the new value is different from the previous value,
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or if there is no previously cached value
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@retval false if the new value is the same as the already cached value
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*/
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bool Cached_item_json::cmp() {
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Json_wrapper wr;
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if (item->val_json(&wr)) {
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null_value = true; /* purecov: inspected */
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return true; /* purecov: inspected */
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}
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if (null_value != item->null_value) {
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null_value = item->null_value;
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if (null_value) return true; // New value is null.
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} else if (null_value) {
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return false; // New and old are null.
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} else if (!m_value->empty() && m_value->compare(wr) == 0) {
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return false; // New and old are equal.
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}
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/*
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Otherwise, old and new are not equal, and new is not null.
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Remember the current value till the next time we're called.
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*/
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*m_value = std::move(wr);
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/*
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The row buffer may change, which would garble the JSON binary
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representation pointed to by m_value. Convert to DOM so that we
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own the copy.
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*/
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m_value->to_dom(current_thd);
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return true;
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}
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void Cached_item_json::copy_to_Item_cache(Item_cache *i_c) {
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down_cast<Item_cache_json *>(i_c)->store_value(item, m_value);
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}
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bool Cached_item_real::cmp(void) {
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DBUG_TRACE;
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double nr = item->val_real();
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DBUG_PRINT("info", ("old: %f, new: %f", value, nr));
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if (null_value != item->null_value || nr != value) {
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null_value = item->null_value;
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value = nr;
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return true;
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}
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return false;
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}
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bool Cached_item_int::cmp(void) {
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DBUG_TRACE;
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longlong nr = item->val_int();
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DBUG_PRINT("info", ("old: 0x%.16llx, new: 0x%.16llx", (ulonglong)value,
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(ulonglong)nr));
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if (null_value != item->null_value || nr != value) {
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null_value = item->null_value;
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value = nr;
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return true;
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}
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return false;
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}
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bool Cached_item_temporal::cmp(void) {
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DBUG_TRACE;
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longlong nr = item->val_temporal_by_field_type();
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DBUG_PRINT("info", ("old: %lld, new: %lld", value, nr));
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if (null_value != item->null_value || nr != value) {
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null_value = item->null_value;
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value = nr;
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return true;
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}
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return false;
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}
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Cached_item_decimal::Cached_item_decimal(Item *it) : Cached_item(it) {
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my_decimal_set_zero(&value);
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}
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void Cached_item_real::copy_to_Item_cache(Item_cache *i_c) {
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down_cast<Item_cache_real *>(i_c)->store_value(item, value);
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}
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void Cached_item_int::copy_to_Item_cache(Item_cache *i_c) {
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down_cast<Item_cache_int *>(i_c)->store_value(item, value);
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}
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void Cached_item_temporal::copy_to_Item_cache(Item_cache *i_c) {
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down_cast<Item_cache_datetime *>(i_c)->store_value(item, value);
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}
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void Cached_item_str::copy_to_Item_cache(Item_cache *i_c) {
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down_cast<Item_cache_str *>(i_c)->store_value(item, value);
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}
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void Cached_item_decimal::copy_to_Item_cache(Item_cache *i_c) {
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down_cast<Item_cache_decimal *>(i_c)->store_value(item, &value);
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}
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bool Cached_item_decimal::cmp() {
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my_decimal tmp;
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my_decimal *ptmp = item->val_decimal(&tmp);
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DBUG_TRACE;
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/*
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NULL handling is wrong here, see Bug#25407964 GROUP BY DESC GIVES WRONG
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RESULT WHEN GROUPS ON DECIMAL AND SEES A NULL.
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*/
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if (null_value != item->null_value ||
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(!item->null_value && my_decimal_cmp(&value, ptmp))) {
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null_value = item->null_value;
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/* Save only not null values */
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if (!null_value) my_decimal2decimal(ptmp, &value);
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return true;
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}
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return false;
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}
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