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oceanbase/src/sql/optimizer/ob_log_limit.cpp
obdev 2d19a9d8f5 [FEAT MERGE]4_1_sql_feature 
Co-authored-by: leslieyuchen <leslieyuchen@gmail.com>
Co-authored-by: Charles0429 <xiezhenjiang@gmail.com>
Co-authored-by: raywill <hustos@gmail.com>
2023-01-28 16:01:28 +08:00

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/**
* Copyright (c) 2021 OceanBase
* OceanBase CE is licensed under Mulan PubL v2.
* You can use this software according to the terms and conditions of the Mulan PubL v2.
* You may obtain a copy of Mulan PubL v2 at:
* http://license.coscl.org.cn/MulanPubL-2.0
* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
* See the Mulan PubL v2 for more details.
*/
#define USING_LOG_PREFIX SQL_OPT
#include "ob_log_limit.h"
#include "ob_log_group_by.h"
#include "ob_log_operator_factory.h"
#include "ob_log_sort.h"
#include "ob_log_table_scan.h"
#include "ob_optimizer_util.h"
#include "ob_opt_est_cost.h"
#include "ob_log_exchange.h"
#include "sql/rewrite/ob_transform_utils.h"
#include "sql/optimizer/ob_join_order.h"
#include "common/ob_smart_call.h"
using namespace oceanbase::sql;
using namespace oceanbase::common;
using namespace oceanbase::sql::log_op_def;
int ObLogLimit::get_op_exprs(ObIArray<ObRawExpr*> &all_exprs)
{
int ret = OB_SUCCESS;
//支持with ties功能，如果存在order by item,需要添加对应的order by item
ObSEArray<ObOrderDirection, 6> order_directions;
if (is_fetch_with_ties() && OB_FAIL(ObOptimizerUtil::split_expr_direction(
order_items_,
all_exprs,
order_directions))) {
LOG_WARN("failed to split expr and direction", K(ret));
} else if (NULL != limit_expr_ && OB_FAIL(all_exprs.push_back(limit_expr_))) {
LOG_WARN("failed to push back expr", K(ret));
} else if (NULL != offset_expr_ && OB_FAIL(all_exprs.push_back(offset_expr_))) {
LOG_WARN("failed to push back expr", K(ret));
} else if (NULL != percent_expr_ && OB_FAIL(all_exprs.push_back(percent_expr_))) {
LOG_WARN("failed to push back expr", K(ret));
} else if (OB_FAIL(ObLogicalOperator::get_op_exprs(all_exprs))) {
LOG_WARN("failed to push back expr", K(ret));
} else {/*do nothing*/ }
return ret;
}
int ObLogLimit::est_cost()
{
int ret = OB_SUCCESS;
double child_cost = 0.0;
ObLogicalOperator *child = NULL;
if (OB_ISNULL(child = get_child(first_child))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(get_stmt()), K(child), K(ret));
} else if (OB_FALSE_IT(child_cost = child->get_cost())) {
} else if (OB_FAIL(inner_est_cost(child->get_card(), child_cost, true, card_, op_cost_))) {
LOG_WARN("failed to est cost", K(ret));
} else {
cost_ = op_cost_ + child_cost;
}
LOG_TRACE("succeed to estimate limit-k cost", K(card_),
K(op_cost_), K(cost_));
return ret;
}
int ObLogLimit::re_est_cost(EstimateCostInfo &param, double &card, double &cost)
{
int ret = OB_SUCCESS;
int64_t offset_count = 0;
double limit_percent = 0.0;
int64_t limit_count = 0;
bool is_null_value = false;
ObLogicalOperator *child = NULL;
if (OB_ISNULL(child = get_child(ObLogicalOperator::first_child)) ||
OB_ISNULL(get_stmt()) || OB_ISNULL(get_plan())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(child), K(ret));
} else if (limit_expr_ != NULL && limit_expr_->has_flag(CNT_DYNAMIC_PARAM)) {
//limit ? do nothing
} else if (NULL != percent_expr_ &&
OB_FAIL(ObTransformUtils::get_percentage_value(percent_expr_,
get_stmt(),
get_plan()->get_optimizer_context().get_params(),
get_plan()->get_optimizer_context().get_exec_ctx(),
&get_plan()->get_optimizer_context().get_allocator(),
limit_percent,
is_null_value))) {
LOG_WARN("failed to get limit value", K(ret));
} else if (!is_null_value && limit_expr_ != NULL &&
OB_FAIL(ObTransformUtils::get_limit_value(limit_expr_,
get_plan()->get_optimizer_context().get_params(),
get_plan()->get_optimizer_context().get_exec_ctx(),
&get_plan()->get_optimizer_context().get_allocator(),
limit_count,
is_null_value))) {
LOG_WARN("failed to get limit value", K(ret));
} else if (!is_null_value && offset_expr_ != NULL &&
OB_FAIL(ObTransformUtils::get_limit_value(offset_expr_,
get_plan()->get_optimizer_context().get_params(),
get_plan()->get_optimizer_context().get_exec_ctx(),
&get_plan()->get_optimizer_context().get_allocator(),
offset_count,
is_null_value))) {
LOG_WARN("failed to get limit value", K(ret));
} else {
double child_card = child->get_card();
double child_cost = child->get_cost();
double op_cost = 0.0;
if (param.need_row_count_ >= 0 && param.need_row_count_ <= card) {
if (is_null_value) {
param.need_row_count_ = 0;
} else if (NULL != percent_expr_) {
param.need_row_count_ = param.need_row_count_ * 100 / limit_percent;
} else if (NULL != offset_expr_) {
param.need_row_count_ += offset_count;
}
} else {
if (is_null_value) {
param.need_row_count_ = 0;
} else if (NULL != percent_expr_) {
param.need_row_count_ = child_card * limit_percent / 100;
} else if (NULL == limit_expr_) {
param.need_row_count_ = child_card;
} else {
param.need_row_count_ = static_cast<double>(limit_count + offset_count);
}
}
if (OB_FAIL(ret)) {
} else if (OB_FAIL(SMART_CALL(child->re_est_cost(param, child_card, child_cost)))) {
LOG_WARN("failed to est child cost", K(ret));
} else if (OB_FAIL(inner_est_cost(child_card, child_cost, false, card, op_cost))) {
LOG_WARN("failed to est count cost", K(ret));
} else {
if (param.override_) {
cost = op_cost + child_cost;
set_op_cost(op_cost);
set_cost(cost);
set_card(card);
}
}
}
return ret;
}
int ObLogLimit::inner_est_cost(double child_card,
double &child_cost,
bool need_re_est_child_cost,
double &card,
double &op_cost)
{
int ret = OB_SUCCESS;
int64_t parallel = 0;
int64_t limit_count = -1;
int64_t offset_count = 0;
double limit_percent = 0.0;
bool is_null_value = false;
ObLogicalOperator *child = NULL;
double re_estimate_card = 0.0;
card = 0.0;
if (OB_ISNULL(get_stmt()) || OB_ISNULL(get_plan()) ||
OB_ISNULL(child = get_child(first_child))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(get_stmt()), K(get_plan()),
K(child), K(ret));
} else if (OB_UNLIKELY((parallel = get_parallel()) < 1)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected parallel degree", K(ret));
} else if (limit_expr_ != NULL && limit_expr_->has_flag(CNT_DYNAMIC_PARAM)) {
//limit ? do nothing
} else if (NULL != percent_expr_ &&
OB_FAIL(ObTransformUtils::get_percentage_value(percent_expr_,
get_stmt(),
get_plan()->get_optimizer_context().get_params(),
get_plan()->get_optimizer_context().get_exec_ctx(),
&get_plan()->get_optimizer_context().get_allocator(),
limit_percent,
is_null_value))) {
LOG_WARN("failed to get limit value", K(ret));
} else if (!is_null_value && limit_expr_ != NULL &&
OB_FAIL(ObTransformUtils::get_limit_value(limit_expr_,
get_plan()->get_optimizer_context().get_params(),
get_plan()->get_optimizer_context().get_exec_ctx(),
&get_plan()->get_optimizer_context().get_allocator(),
limit_count,
is_null_value))) {
LOG_WARN("failed to get limit value", K(ret));
} else if (!is_null_value && offset_expr_ != NULL &&
OB_FAIL(ObTransformUtils::get_limit_value(offset_expr_,
get_plan()->get_optimizer_context().get_params(),
get_plan()->get_optimizer_context().get_exec_ctx(),
&get_plan()->get_optimizer_context().get_allocator(),
offset_count,
is_null_value))) {
LOG_WARN("failed to get limit value", K(ret));
} else if (is_null_value) {
re_estimate_card = 0;
card = 0;
} else if (NULL != percent_expr_) {
re_estimate_card = child_card * limit_percent / 100;
card = re_estimate_card - offset_count;
} else if (NULL == limit_expr_) {
re_estimate_card = child_card;
card = child_card - offset_count;
} else {
re_estimate_card = static_cast<double>(limit_count + offset_count) * parallel;
card = std::min(static_cast<double>(limit_count) * parallel, child_card - offset_count);
}
if (OB_SUCC(ret)) {
ObOptimizerContext &opt_ctx = get_plan()->get_optimizer_context();
re_estimate_card = std::min(re_estimate_card, child_card);
card = std::max(card, 0.0);
if (!is_calc_found_rows_ && NULL == percent_expr_ && need_re_est_child_cost) {
EstimateCostInfo param;
param.need_row_count_ = re_estimate_card;
param.override_ = false;
if (OB_FAIL(child->re_est_cost(param, child_card, child_cost))) {
LOG_WARN("failed to re-est cost", K(ret));
} else {
op_cost = ObOptEstCost::cost_get_rows(re_estimate_card, opt_ctx.get_cost_model_type());
}
} else {
op_cost = ObOptEstCost::cost_get_rows(child_card, opt_ctx.get_cost_model_type());
}
}
return ret;
}
int ObLogLimit::check_output_dep_specific(ObRawExprCheckDep &checker)
{
int ret = OB_SUCCESS;
if (NULL != limit_expr_) {
if (OB_FAIL(checker.check(*limit_expr_))) {
LOG_WARN("failed to check limit_count_", K(*limit_expr_), K(ret));
}
} else { /* Do nothing */ }
if (OB_SUCC(ret)) {
if (NULL != offset_expr_) {
if (OB_FAIL(checker.check(*offset_expr_))) {
LOG_WARN("failed to check limit_offset_", K(offset_expr_), K(ret));
}
} else { /* Do nothing */ }
}
if (OB_SUCC(ret)) {
if (NULL != percent_expr_) {
if (OB_FAIL(checker.check(*percent_expr_))) {
LOG_WARN("failed to check limit_percent_", K(percent_expr_), K(ret));
}
}
}
if (OB_SUCC(ret) && is_fetch_with_ties()) {
for (int64_t i = 0; OB_SUCC(ret) && i < order_items_.count(); ++i) {
ObRawExpr *cur_expr = order_items_.at(i).expr_;
if (OB_ISNULL(cur_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null ptr", K(cur_expr), K(ret));
} else if (OB_FAIL(checker.check(*cur_expr))) {
LOG_WARN("failed to check expr", K(cur_expr), K(ret));
} else {/*do nothing*/}
}
}
return ret;
}
int ObLogLimit::get_plan_item_info(PlanText &plan_text,
ObSqlPlanItem &plan_item)
{
int ret = OB_SUCCESS;
if (OB_FAIL(ObLogicalOperator::get_plan_item_info(plan_text, plan_item))) {
LOG_WARN("failed to get plan item info", K(ret));
} else if (NULL != limit_expr_ || NULL != offset_expr_ || NULL != percent_expr_) {
BEGIN_BUF_PRINT;
ObRawExpr *limit = limit_expr_;
ObRawExpr *offset = offset_expr_;
ObRawExpr *percent = percent_expr_;
EXPLAIN_PRINT_EXPR(limit, type);
ret = BUF_PRINTF(", ");
EXPLAIN_PRINT_EXPR(offset, type);
if (percent_expr_ != NULL) {
BUF_PRINTF(", ");
EXPLAIN_PRINT_EXPR(percent, type);
}
if (is_fetch_with_ties_) {
BUF_PRINTF(", ");
BUF_PRINTF("with_ties(%s)", "true");
}
END_BUF_PRINT(plan_item.special_predicates_,
plan_item.special_predicates_len_);
}
return ret;
}
int ObLogLimit::inner_replace_op_exprs(
const common::ObIArray<std::pair<ObRawExpr *, ObRawExpr*>> &to_replace_exprs)
{
int ret = OB_SUCCESS;
if (NULL != limit_expr_ && OB_FAIL(replace_expr_action(to_replace_exprs, limit_expr_))) {
LOG_WARN("failed to replace limit expr", K(ret));
} else if (NULL != offset_expr_ && OB_FAIL(replace_expr_action(to_replace_exprs, offset_expr_))) {
LOG_WARN("failed to replace offset expr", K(ret));
} else if (NULL != percent_expr_ && OB_FAIL(replace_expr_action(to_replace_exprs, percent_expr_))) {
LOG_WARN("failed to replace percent expr", K(ret));
}
for (int64_t i = 0; OB_SUCC(ret) && i < order_items_.count(); ++i) {
if (OB_ISNULL(order_items_.at(i).expr_)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null ", K(ret));
} else if (OB_FAIL(replace_expr_action(to_replace_exprs, order_items_.at(i).expr_))) {
LOG_WARN("failed to adjust order expr with onetime", K(ret));
}
}
return ret;
}
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