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oceanbase/src/sql/optimizer/ob_log_limit.cpp
oceanbase-admin cea7de1475 init push
2021-05-31 22:56:52 +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"
using namespace oceanbase::sql;
using namespace oceanbase::common;
using namespace oceanbase::sql::log_op_def;
int ObLogLimit::copy_without_child(ObLogicalOperator*& out)
{
int ret = OB_SUCCESS;
out = NULL;
ObLogicalOperator* op = NULL;
ObLogLimit* limit = NULL;
if (OB_FAIL(clone(op))) {
LOG_WARN("failed to clone ObLogLimit", K(ret));
} else if (OB_ISNULL(limit = static_cast<ObLogLimit*>(op))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("failed to cast ObLogicalOperator * to ObLogLimit *", K(ret));
} else {
limit->set_calc_found_rows(is_calc_found_rows_);
limit->set_has_union_child(has_union_child_);
limit->set_fetch_with_ties(is_fetch_with_ties());
limit->set_limit_count(limit_count_);
limit->set_limit_offset(limit_offset_);
limit->set_limit_percent(limit_percent_);
out = limit;
}
return ret;
}
int ObLogLimit::allocate_exchange_post(AllocExchContext* ctx)
{
int ret = OB_SUCCESS;
bool is_basic = false;
bool should_push_limit = (!is_calc_found_rows_ && (limit_percent_ == NULL));
ObLogicalOperator* exchange_point = NULL;
ObExchangeInfo exch_info;
if (OB_ISNULL(ctx)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ctx), K(ret));
} else if (OB_FAIL(compute_basic_sharding_info(ctx, is_basic))) {
LOG_WARN("failed to compute basic sharding info", K(ret));
} else if (is_basic) {
LOG_TRACE("is basic sharding info", K(sharding_info_));
} else if (OB_FAIL(push_down_limit(
ctx, limit_count_, limit_offset_, should_push_limit, is_fetch_with_ties(), exchange_point))) {
LOG_WARN("failed to push down limit", K(ret));
} else if (OB_ISNULL(exchange_point)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(exchange_point), K(ret));
} else if (OB_FAIL(exchange_point->allocate_exchange_nodes_below(first_child, *ctx, exch_info))) {
LOG_WARN("failed to allocate exchange nodes below", K(ret));
} else {
sharding_info_.set_location_type(OB_TBL_LOCATION_LOCAL);
}
return ret;
}
int ObLogLimit::transmit_op_ordering()
{
int ret = OB_SUCCESS;
bool need_sort = false;
if (OB_FAIL(check_need_sort_below_node(0, expected_ordering_, need_sort))) {
LOG_WARN("failed to check need sort", K(ret));
} else if (!need_sort) {
// do nothing
} else if (OB_FAIL(allocate_sort_below(0, expected_ordering_))) {
LOG_WARN("failed to allocate sort", K(ret));
}
if (OB_SUCC(ret)) {
if (OB_FAIL(ObLogicalOperator::transmit_op_ordering())) {
LOG_WARN("failed to transmit op ordering", K(ret));
}
}
return ret;
}
int ObLogLimit::allocate_expr_pre(ObAllocExprContext& ctx)
{
int ret = OB_SUCCESS;
ObSEArray<ObRawExpr*, 6> order_exprs;
ObSEArray<ObOrderDirection, 6> order_directions;
if (is_fetch_with_ties() &&
OB_FAIL(ObOptimizerUtil::split_expr_direction(get_expected_ordering(), order_exprs, order_directions))) {
LOG_WARN("failed to split expr and direction", K(ret));
} else if (OB_FAIL(add_exprs_to_ctx(ctx, order_exprs))) {
LOG_WARN("fail to add expr to ctx", K(ret));
} else if (OB_FAIL(ObLogicalOperator::allocate_expr_pre(ctx))) {
LOG_WARN("failed to add parent need expr", K(ret));
} else { /*do nothing*/
}
return ret;
}
int ObLogLimit::est_cost()
{
int ret = OB_SUCCESS;
int64_t limit_count = -1;
int64_t offset_count = 0;
double percentage = 0.0;
bool is_null_value = false;
if (OB_ISNULL(get_child(first_child)) || OB_ISNULL(get_plan())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("Limit's child not expected to be NULL", K(ret));
} else if (limit_count_ != NULL && OB_FAIL(ObTransformUtils::get_limit_value(limit_count_,
get_plan()->get_stmt(),
get_plan()->get_optimizer_context().get_params(),
get_plan()->get_optimizer_context().get_session_info(),
&get_plan()->get_optimizer_context().get_allocator(),
limit_count,
is_null_value))) {
LOG_WARN("Get limit count num error", K(ret));
} else if (!is_null_value && limit_offset_ != NULL &&
OB_FAIL(ObTransformUtils::get_limit_value(limit_offset_,
get_plan()->get_stmt(),
get_plan()->get_optimizer_context().get_params(),
get_plan()->get_optimizer_context().get_session_info(),
&get_plan()->get_optimizer_context().get_allocator(),
offset_count,
is_null_value))) {
LOG_WARN("Get limit offset num error", K(ret));
} else if (!is_null_value && limit_percent_ != NULL &&
OB_FAIL(get_percentage_value(limit_percent_, percentage, is_null_value))) {
LOG_WARN("failed to get percentage value", K(ret));
} else {
double child_card = get_child(first_child)->get_card();
double limit_count_double = 0.0;
double offset_count_double = 0.0;
double scan_count_double = 0.0;
if (limit_count_ != NULL || limit_percent_ != NULL) {
limit_count = is_null_value ? 0 : limit_count;
offset_count = is_null_value ? 0 : offset_count;
if (limit_percent_ != NULL) {
limit_count_double = child_card * percentage / 100.0;
offset_count_double = static_cast<double>(offset_count);
} else {
limit_count_double = static_cast<double>(limit_count);
offset_count_double = static_cast<double>(offset_count);
}
scan_count_double = limit_count_double + offset_count_double;
if (scan_count_double <= child_card) {
set_card(limit_count_double);
} else {
limit_count_double = child_card - offset_count_double;
set_card(limit_count_double >= 0.0 ? limit_count_double : 0.0);
}
if (!is_calc_found_rows_ && NULL == limit_percent_) {
bool re_est = false;
if (OB_FAIL(get_child(first_child)->re_est_cost(this, scan_count_double, re_est))) {
LOG_WARN("Failed to re est cost", K(ret));
}
}
} else {
offset_count_double = static_cast<double>(offset_count);
if (OB_UNLIKELY(offset_count_double < 0)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("offset count double should greater than 0", K(ret), K(offset_count_double));
} else {
limit_count_double = is_null_value ? 0 : child_card - offset_count_double;
set_card(limit_count_double >= 0.0 ? limit_count_double : 0.0);
}
}
if (OB_SUCC(ret)) {
double op_cost = ObOptEstCost::cost_limit(get_child(first_child)->get_card());
set_op_cost(op_cost);
set_cost(get_child(first_child)->get_cost() + op_cost);
set_width(get_child(first_child)->get_width());
}
}
return ret;
}
int ObLogLimit::re_est_cost(const ObLogicalOperator* parent, double need_row_count, bool& re_est)
{
int ret = OB_SUCCESS;
UNUSED(parent);
re_est = false;
if (OB_UNLIKELY(need_row_count < 0.0)) {
ret = OB_INVALID_ARGUMENT;
LOG_WARN("Need row count should not less than 0", K(ret));
} else if (need_row_count < get_card()) {
card_ = need_row_count;
int64_t offset_count = 0;
ObLogicalOperator* child = NULL;
bool is_null_value = false;
if (OB_ISNULL(child = get_child(first_child)) || OB_ISNULL(get_plan())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(child));
} else if (OB_FAIL(ObTransformUtils::get_limit_value(limit_offset_,
get_plan()->get_stmt(),
get_plan()->get_optimizer_context().get_params(),
get_plan()->get_optimizer_context().get_session_info(),
&get_plan()->get_optimizer_context().get_allocator(),
offset_count,
is_null_value))) {
LOG_WARN("Get limit offset num error", K(ret));
} else if (OB_FAIL(child->re_est_cost(this, static_cast<double>(offset_count) + need_row_count, re_est))) {
LOG_WARN("Failed to re_est child cost", K(ret));
} else {
re_est = true;
double op_cost = ObOptEstCost::cost_limit(child->get_card());
set_op_cost(op_cost);
set_cost(child->get_cost() + op_cost);
}
}
return ret;
}
uint64_t ObLogLimit::hash(uint64_t seed) const
{
uint64_t hash_value = seed;
hash_value = do_hash(is_calc_found_rows_, hash_value);
hash_value = do_hash(has_union_child_, hash_value);
hash_value = do_hash(is_top_limit_, hash_value);
hash_value = ObOptimizerUtil::hash_expr(limit_count_, hash_value);
hash_value = ObOptimizerUtil::hash_expr(limit_offset_, hash_value);
hash_value = ObLogicalOperator::hash(hash_value);
return hash_value;
}
int ObLogLimit::check_output_dep_specific(ObRawExprCheckDep& checker)
{
int ret = OB_SUCCESS;
if (NULL != limit_count_) {
if (OB_FAIL(checker.check(*limit_count_))) {
LOG_WARN("failed to check limit_count_", K(*limit_count_), K(ret));
}
} else { /* Do nothing */
}
if (OB_SUCC(ret)) {
if (NULL != limit_offset_) {
if (OB_FAIL(checker.check(*limit_offset_))) {
LOG_WARN("failed to check limit_offset_", K(limit_offset_), K(ret));
}
} else { /* Do nothing */
}
}
if (OB_SUCC(ret)) {
if (NULL != limit_percent_) {
if (OB_FAIL(checker.check(*limit_percent_))) {
LOG_WARN("failed to check limit_percent_", K(limit_percent_), K(ret));
}
}
}
if (OB_SUCC(ret) && is_fetch_with_ties()) {
ObIArray<OrderItem>& order_items = get_expected_ordering();
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::print_my_plan_annotation(char* buf, int64_t& buf_len, int64_t& pos, ExplainType type)
{
int ret = OB_SUCCESS;
if (NULL != limit_count_ || NULL != limit_offset_ || NULL != limit_percent_) {
if (OB_FAIL(BUF_PRINTF(", "))) {
LOG_WARN("BUF_PRINTF fails", K(ret));
} else {
ObRawExpr* limit = limit_count_;
ObRawExpr* offset = limit_offset_;
ObRawExpr* percent = limit_percent_;
EXPLAIN_PRINT_EXPR(limit, type);
BUF_PRINTF(", ");
EXPLAIN_PRINT_EXPR(offset, type);
if (limit_percent_ != NULL) {
BUF_PRINTF(", ");
EXPLAIN_PRINT_EXPR(percent, type);
}
if (is_fetch_with_ties_) {
BUF_PRINTF(", ");
BUF_PRINTF("with_ties(%s)", "true");
}
}
}
return ret;
}
int ObLogLimit::inner_append_not_produced_exprs(ObRawExprUniqueSet& raw_exprs) const
{
int ret = OB_SUCCESS;
OZ(raw_exprs.append(limit_count_));
OZ(raw_exprs.append(limit_offset_));
if (NULL != limit_percent_) {
OZ(raw_exprs.append(limit_percent_));
}
return ret;
}