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oceanbase/src/sql/optimizer/ob_opt_selectivity.cpp
Monk-Liu f1d066b4bd [opt_stats]: Fix online_osg bugs
2023-03-02 17:41:48 +00:00

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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 "sql/optimizer/ob_opt_selectivity.h"
#include <math.h>
#include "common/object/ob_obj_compare.h"
#include "sql/session/ob_sql_session_info.h"
#include "sql/session/ob_basic_session_info.h"
#include "share/schema/ob_part_mgr_util.h"
#include "sql/resolver/expr/ob_raw_expr_util.h"
#include "sql/rewrite/ob_query_range.h"
#include "sql/optimizer/ob_opt_est_utils.h"
#include "sql/optimizer/ob_optimizer.h"
#include "sql/optimizer/ob_optimizer_util.h"
#include "sql/rewrite/ob_transform_utils.h"
#include "share/stat/ob_opt_stat_manager.h"
#include "share/stat/ob_opt_column_stat_cache.h"
#include "sql/optimizer/ob_logical_operator.h"
#include "sql/optimizer/ob_join_order.h"
#include "common/ob_smart_call.h"
using namespace oceanbase::common;
using namespace oceanbase::share::schema;
namespace oceanbase
{
namespace sql
{
inline double revise_ndv(double ndv) { return ndv < 1.0 ? 1.0 : ndv; }
int OptColumnMeta::assign(const OptColumnMeta &other)
{
int ret = OB_SUCCESS;
column_id_ = other.column_id_;
ndv_ = other.ndv_;
num_null_ = other.num_null_;
avg_len_ = other.avg_len_;
hist_scale_ = other.hist_scale_;
min_val_ = other.min_val_;
max_val_ = other.max_val_;
min_max_inited_ = other.min_max_inited_;
return ret;
}
void OptColumnMeta::init(const uint64_t column_id,
const double ndv,
const double num_null,
const double avg_len)
{
column_id_ = column_id;
ndv_ = ndv;
num_null_ = num_null;
avg_len_ = avg_len;
}
int OptTableMeta::assign(const OptTableMeta &other)
{
int ret = OB_SUCCESS;
table_id_ = other.table_id_;
ref_table_id_ = other.ref_table_id_;
rows_ = other.rows_;
stat_type_ = other.stat_type_;
if (OB_FAIL(all_used_parts_.assign(other.all_used_parts_))) {
LOG_WARN("failed to assign all used parts", K(ret));
} else if (OB_FAIL(column_metas_.assign(other.column_metas_))) {
LOG_WARN("failed to assign all csata", K(ret));
} else if (OB_FAIL(pk_ids_.assign(other.pk_ids_))) {
LOG_WARN("failed to assign pk ids", K(ret));
}
return ret;
}
int OptTableMeta::init(const uint64_t table_id,
const uint64_t ref_table_id,
const int64_t rows,
const int64_t stat_type,
ObSqlSchemaGuard &schema_guard,
ObIArray<int64_t> &all_used_part_id,
ObIArray<uint64_t> &column_ids,
const OptSelectivityCtx &ctx)
{
int ret = OB_SUCCESS;
const ObTableSchema *table_schema = NULL;
uint64_t column_id = OB_INVALID_ID;
//init common member variable
table_id_ = table_id;
ref_table_id_ = ref_table_id;
rows_ = rows;
stat_type_ = stat_type;
if (OB_FAIL(all_used_parts_.assign(all_used_part_id))) {
LOG_WARN("failed to assign all used partition ids", K(ret));
} else if (OB_FAIL(schema_guard.get_table_schema(table_id_, ref_table_id_, ctx.get_stmt(), table_schema))) {
LOG_WARN("failed to get table schmea", K(ret), K(ref_table_id_));
} else if (OB_ISNULL(table_schema)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null table schema", K(ret), K(ref_table_id_));
} else if (OB_FAIL(column_metas_.prepare_allocate(column_ids.count()))) {
LOG_WARN("failed to init column metas", K(ret));
} else {/*do nothing*/}
// init pkey ids
const ObRowkeyInfo &rowkey_info = table_schema->get_rowkey_info();
for (int64_t i = 0; OB_SUCC(ret) && i < rowkey_info.get_size(); ++i) {
if (OB_FAIL(rowkey_info.get_column_id(i, column_id))) {
LOG_WARN("failed to get column id", K(ret));
} else if (column_id < OB_END_RESERVED_COLUMN_ID_NUM) {
if (table_schema->is_heap_table()) {
// partition column will add to primary key for heap table
pk_ids_.reset();
} else { /* do nothing */ }
break;
} else if (OB_FAIL(pk_ids_.push_back(column_id))) {
LOG_WARN("failed to push back column id", K(ret));
}
}
//init column ndv
for (int64_t i = 0; OB_SUCC(ret) && i < column_ids.count(); ++i) {
column_id = column_ids.at(i);
int64_t global_ndv = 0;
int64_t num_null = 0;
int64_t avg_len = 0;
bool is_single_pkey = (1 == pk_ids_.count() && pk_ids_.at(0) == column_id);
// get global llc bitmap
if (is_single_pkey) {
global_ndv = rows_;
num_null = 0;
} else if (use_default_stat()) {
global_ndv = std::min(rows, 100L);
num_null = rows * EST_DEF_COL_NULL_RATIO;
} else if (OB_ISNULL(ctx.get_opt_stat_manager()) || OB_ISNULL(ctx.get_session_info())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(ctx.get_opt_stat_manager()),
K(ctx.get_session_info()));
} else if (OB_FAIL(ctx.get_opt_stat_manager()->get_column_stat(ctx.get_session_info()->get_effective_tenant_id(),
ref_table_id_,
all_used_part_id,
column_id,
&global_ndv,
&num_null,
&avg_len))) {
LOG_WARN("failed to get column stats", K(ret));
} else if (0 == global_ndv && 0 == num_null) {
global_ndv = std::min(rows, 100L);
num_null = rows * EST_DEF_COL_NULL_RATIO;
} else if (0 == global_ndv && num_null > 0) {
global_ndv = 1;
}
if (OB_SUCC(ret)) {
column_metas_.at(i).init(column_id, global_ndv, num_null, avg_len);
}
}
return ret;
}
const OptColumnMeta* OptTableMeta::get_column_meta(const uint64_t column_id) const
{
const OptColumnMeta* column_meta = NULL;
for (int64_t i = 0; NULL == column_meta && i < column_metas_.count(); ++i) {
if (column_metas_.at(i).get_column_id() == column_id) {
column_meta = &column_metas_.at(i);
}
}
return column_meta;
}
int OptTableMetas::copy_table_meta_info(const OptTableMeta &src_meta, OptTableMeta *&dst_meta)
{
int ret = OB_SUCCESS;
if (OB_FAIL(table_metas_.push_back(src_meta))) {
LOG_WARN("failed to push back table meta");
} else {
dst_meta = &table_metas_.at(table_metas_.count() - 1);
}
return ret;
}
int OptTableMetas::copy_table_meta_info(const OptTableMetas &table_metas, const uint64_t table_id)
{
int ret = OB_SUCCESS;
const OptTableMeta *table_meta = table_metas.get_table_meta_by_table_id(table_id);
OptTableMeta *dummy_meta = NULL;
if (OB_ISNULL(table_meta)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null table meta", K(ret), K(table_id));
} else if (OB_FAIL(copy_table_meta_info(*table_meta, dummy_meta))) {
LOG_WARN("failed to copy table meta info", K(ret));
}
return ret;
}
int OptTableMetas::add_base_table_meta_info(OptSelectivityCtx &ctx,
const uint64_t table_id,
const uint64_t ref_table_id,
const int64_t rows,
ObIArray<int64_t> &all_used_part_id,
ObIArray<uint64_t> &column_ids,
const int64_t stat_type,
int64_t last_analyzed)
{
int ret = OB_SUCCESS;
ObSqlSchemaGuard *schema_guard = ctx.get_sql_schema_guard();
OptTableMeta *table_meta = NULL;
if (OB_ISNULL(schema_guard)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null sql schema guard", K(schema_guard));
} else if (OB_ISNULL(table_meta = table_metas_.alloc_place_holder())) {
ret = OB_ALLOCATE_MEMORY_FAILED;
LOG_WARN("failed to allocate place holder for table meta", K(ret));
} else if (OB_FAIL(table_meta->init(table_id, ref_table_id, rows, stat_type,
*schema_guard, all_used_part_id, column_ids, ctx))) {
LOG_WARN("failed to init new tstat", K(ret));
} else {
table_meta->set_version(last_analyzed);
LOG_TRACE("add base table meta info success", K(*table_meta));
}
return ret;
}
// set stmt child is select stmt, not generate table. To mentain meta info for set stmt,
// mock a table for set stmt child. e.g. first child stmt use table id = 1, second child stmt
// use table_id = 2, ...
int OptTableMetas::add_set_child_stmt_meta_info(const ObDMLStmt *parent_stmt,
const ObSelectStmt *child_stmt,
const uint64_t table_id,
const OptTableMetas &child_table_metas,
const OptSelectivityCtx &child_ctx,
const double child_rows)
{
int ret = OB_SUCCESS;
OptTableMeta *table_meta = NULL;
OptColumnMeta *column_meta = NULL;
ObSEArray<ObRawExpr*, 1> exprs;
ObRawExpr *select_expr = NULL;
if (OB_ISNULL(parent_stmt) || OB_ISNULL(child_stmt)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null stmt", K(ret), K(parent_stmt), K(child_stmt));
} else if (OB_ISNULL(table_meta = table_metas_.alloc_place_holder())) {
ret = OB_ALLOCATE_MEMORY_FAILED;
LOG_WARN("failed to allocate place holder for table meta", K(ret));
} else {
const double table_rows = child_rows < 1.0 ? 1.0 : child_rows;
table_meta->set_table_id(table_id);
table_meta->set_ref_table_id(OB_INVALID_ID);
table_meta->set_rows(table_rows);
for (int64_t i = 0; OB_SUCC(ret) && i < child_stmt->get_select_item_size(); ++i) {
exprs.reset();
double ndv = 1;
double num_null = 0;
double avg_len = 0;
if (OB_ISNULL(select_expr = child_stmt->get_select_items().at(i).expr_)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null select expr", K(ret));
} else if (select_expr->is_set_op_expr()) {
const int64_t set_epxr_idx = static_cast<ObSetOpRawExpr *>(select_expr)->get_idx();
if (OB_FAIL(get_set_stmt_output_statistics(*child_stmt, child_table_metas,
set_epxr_idx, ndv, num_null, avg_len))) {
LOG_WARN("failed to get set stmt output statistics", K(ret));
} else {
ndv = std::min(ndv, table_rows);
}
} else if (OB_FAIL(exprs.push_back(select_expr))) {
LOG_WARN("Failed to push back column expr", K(ret));
} else if (OB_FAIL(ObOptSelectivity::calculate_distinct(child_table_metas,
child_ctx,
exprs,
table_rows,
ndv))) {
LOG_WARN("failed to calculate distinct", K(ret));
}
if (OB_SUCC(ret)) {
if (OB_ISNULL(column_meta = table_meta->get_column_metas().alloc_place_holder())) {
ret = OB_ALLOCATE_MEMORY_FAILED;
LOG_WARN("failed to allocate place holder for column meta", K(ret));
} else {
column_meta->init(OB_APP_MIN_COLUMN_ID + i, revise_ndv(ndv), num_null, avg_len);
column_meta->set_min_max_inited(true);
}
}
}
if (OB_SUCC(ret)) {
LOG_TRACE("succeed add set table meta info", K(child_table_metas), K(*this));
}
}
return ret;
}
int OptTableMetas::add_generate_table_meta_info(const ObDMLStmt *parent_stmt,
const ObSelectStmt *child_stmt,
const uint64_t table_id,
const OptTableMetas &child_table_metas,
const OptSelectivityCtx &child_ctx,
const double child_rows)
{
int ret = OB_SUCCESS;
OptTableMeta *table_meta = NULL;
OptColumnMeta *column_meta = NULL;
ObSEArray<ColumnItem, 8> column_items;
ObSEArray<ObRawExpr*, 1> exprs;
ObRawExpr *select_expr = NULL;
if (OB_ISNULL(parent_stmt) || OB_ISNULL(child_stmt)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null stmt", K(ret), K(parent_stmt), K(child_stmt));
} else if (OB_ISNULL(table_meta = table_metas_.alloc_place_holder())) {
ret = OB_ALLOCATE_MEMORY_FAILED;
LOG_WARN("failed to allocate place holder for table meta", K(ret));
} else if (OB_FAIL(parent_stmt->get_column_items(table_id, column_items))) {
LOG_WARN("failed to get column items", K(ret));
} else {
const double table_rows = child_rows < 1.0 ? 1.0 : child_rows;
table_meta->set_table_id(table_id);
table_meta->set_ref_table_id(OB_INVALID_ID);
table_meta->set_rows(table_rows);
for (int64_t i = 0; OB_SUCC(ret) && i < column_items.count(); ++i) {
const ColumnItem &column_item = column_items.at(i);
exprs.reset();
double ndv = 1;
double num_null = 0;
double avg_len = 0;
int64_t idx = column_item.column_id_ - OB_APP_MIN_COLUMN_ID;
if (OB_UNLIKELY(idx < 0 || idx >= child_stmt->get_select_item_size())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpect column", K(ret), K(column_item), K(child_stmt->get_select_items()));
} else if (OB_ISNULL(select_expr = child_stmt->get_select_item(idx).expr_)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null select expr", K(ret));
} else if (select_expr->is_set_op_expr()) {
const int64_t set_epxr_idx = static_cast<ObSetOpRawExpr *>(select_expr)->get_idx();
if (OB_FAIL(get_set_stmt_output_statistics(*child_stmt, child_table_metas,
set_epxr_idx, ndv, num_null, avg_len))) {
LOG_WARN("failed to get set stmt output statistics", K(ret));
} else {
ndv = std::min(ndv, table_rows);
}
} else if (OB_FAIL(exprs.push_back(select_expr))) {
LOG_WARN("Failed to push back column expr", K(ret));
} else if (OB_FAIL(ObOptSelectivity::calculate_distinct(child_table_metas,
child_ctx,
exprs,
table_rows,
ndv))) {
LOG_WARN("failed to calculate distinct", K(ret));
}
if (OB_SUCC(ret)) {
/*TODO:@yibo num_null*/
if (OB_ISNULL(column_meta = table_meta->get_column_metas().alloc_place_holder())) {
ret = OB_ALLOCATE_MEMORY_FAILED;
LOG_WARN("failed to allocate place holder for column meta", K(ret));
} else {
column_meta->init(column_item.column_id_, revise_ndv(ndv), num_null, avg_len);
column_meta->set_min_max_inited(true);
if (select_expr->is_column_ref_expr()) {
ObColumnRefRawExpr *col = static_cast<ObColumnRefRawExpr *>(select_expr);
const OptColumnMeta *child_column_meta = child_table_metas.get_column_meta_by_table_id(
col->get_table_id(), col->get_column_id());
if (OB_NOT_NULL(child_column_meta) && child_column_meta->get_min_max_inited()) {
column_meta->set_min_value(child_column_meta->get_min_value());
column_meta->set_max_value(child_column_meta->get_max_value());
}
}
}
}
}
if (OB_SUCC(ret)) {
LOG_TRACE("succeed add generate table meta info", K(child_table_metas), K(*this));
}
}
return ret;
}
int OptTableMetas::get_set_stmt_output_statistics(const ObSelectStmt &stmt,
const OptTableMetas &child_table_metas,
const int64_t idx,
double &ndv,
double &num_null,
double &avg_len)
{
int ret = OB_SUCCESS;
ndv = 0;
num_null = 0;
avg_len = 0;
uint64_t column_id = OB_APP_MIN_COLUMN_ID + idx;
const OptColumnMeta *column_meta = NULL;
for (int64_t i = 0; OB_SUCC(ret) && i < stmt.get_set_query().count(); ++i) {
if (OB_ISNULL(stmt.get_set_query().at(i))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null set query", K(ret));
} else if (OB_INVALID_ID != stmt.get_set_query().at(i)->get_dblink_id()) {
// skip
} else if (OB_ISNULL(column_meta = child_table_metas.get_column_meta_by_table_id(i, column_id))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null column meta info", K(ret));
} else if (ObSelectStmt::SetOperator::UNION == stmt.get_set_op()) {
// ndv1 + ndv2
ndv += column_meta->get_ndv();
num_null += column_meta->get_num_null();
avg_len = std::max(avg_len, column_meta->get_avg_len());
} else if (ObSelectStmt::SetOperator::INTERSECT == stmt.get_set_op()) {
// min(ndv1, ndv2)
if (0 == i) {
ndv = column_meta->get_ndv();
num_null = column_meta->get_num_null();
avg_len = column_meta->get_avg_len();
} else {
ndv = std::min(ndv, column_meta->get_ndv());
num_null = std::min(num_null, column_meta->get_num_null());
avg_len = std::min(avg_len, column_meta->get_avg_len());
}
} else if (ObSelectStmt::SetOperator::EXCEPT == stmt.get_set_op()) {
// max(ndv1 - ndv2, 1)
if (0 == i) {
ndv = column_meta->get_ndv();
num_null = column_meta->get_num_null();
avg_len = column_meta->get_avg_len();
} else {
ndv = std::max(ndv - column_meta->get_ndv(), 1.0);
num_null = std::max(num_null - column_meta->get_num_null(), 1.0);
avg_len = std::min(avg_len, column_meta->get_avg_len());
}
} else if (ObSelectStmt::SetOperator::RECURSIVE == stmt.get_set_op()) {
// ndv1
ndv = column_meta->get_ndv();
num_null = column_meta->get_num_null();
avg_len = column_meta->get_avg_len();
break;
}
}
return ret;
}
const OptTableMeta* OptTableMetas::get_table_meta_by_table_id(const uint64_t table_id) const
{
const OptTableMeta *table_meta = NULL;
for (int64_t i = 0; NULL == table_meta && i < table_metas_.count(); ++i) {
if (table_id == table_metas_.at(i).get_table_id()) {
table_meta = &table_metas_.at(i);
}
}
return table_meta;
}
OptTableMeta* OptTableMetas::get_table_meta_by_table_id(const uint64_t table_id)
{
OptTableMeta *table_meta = NULL;
for (int64_t i = 0; NULL == table_meta && i < table_metas_.count(); ++i) {
if (table_id == table_metas_.at(i).get_table_id()) {
table_meta = &table_metas_.at(i);
}
}
return table_meta;
}
const OptColumnMeta* OptTableMetas::get_column_meta_by_table_id(const uint64_t table_id,
const uint64_t column_id) const
{
const OptColumnMeta *column_meta = NULL;
const OptTableMeta *table_meta = get_table_meta_by_table_id(table_id);
if (OB_NOT_NULL(table_meta)) {
column_meta = table_meta->get_column_meta(column_id);
}
return column_meta;
}
int ObOptSelectivity::calculate_selectivity(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObIArray<ObRawExpr*> &predicates,
double &selectivity,
ObIArray<ObExprSelPair> &all_predicate_sel)
{
int ret = OB_SUCCESS;
selectivity = 1.0;
ObSEArray<ObRawExpr *, 4> join_conditions;
ObSEArray<RangeExprs, 3> range_conditions;
ObRawExpr *qual = NULL;
double tmp_selectivity = 1.0;
bool need_skip = false;
for (int64_t i = 0; OB_SUCC(ret) && i < predicates.count(); ++i) {
qual = predicates.at(i);
LOG_TRACE("calculate qual selectivity", "expr", PNAME(qual));
if (OB_ISNULL(qual)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret));
} else if (OB_FAIL(check_qual_later_calculation(table_metas, ctx, *qual, all_predicate_sel,
join_conditions,range_conditions, need_skip))) {
LOG_WARN("failed to check qual later calculation", K(ret));
} else if (need_skip) {
// do nothing
} else if (OB_FAIL(calculate_qual_selectivity(table_metas, ctx, *qual,
tmp_selectivity, all_predicate_sel))) {
LOG_WARN("failed to calculate one qual selectivity", K(*qual), K(ret));
} else {
tmp_selectivity = revise_between_0_1(tmp_selectivity);
selectivity *= tmp_selectivity;
}
LOG_TRACE("after calculate one qual selectivity", K(need_skip), K(tmp_selectivity), K(selectivity));
}
for (int64_t i = 0 ; OB_SUCC(ret) && i < range_conditions.count() ; ++i) {
tmp_selectivity = 1.0;
ObColumnRefRawExpr *col_expr = range_conditions.at(i).column_expr_;
if (OB_ISNULL(col_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else if (OB_FAIL(get_column_range_sel(table_metas, ctx, *col_expr,
range_conditions.at(i).range_exprs_,
tmp_selectivity))) {
LOG_WARN("failed to get column range selectivity", K(ret));
} else {
tmp_selectivity = revise_between_0_1(tmp_selectivity);
selectivity *= tmp_selectivity;
if (range_conditions.at(i).range_exprs_.count() > 1) {
if (OB_FAIL(add_var_to_array_no_dup(all_predicate_sel,
ObExprSelPair(col_expr, tmp_selectivity, true)))) {
LOG_WARN("failed to add selectivity to plan", K(ret), K(qual), K(tmp_selectivity));
}
}
}
}
if (OB_SUCC(ret) && ctx.get_left_rel_ids() != NULL && ctx.get_right_rel_ids() != NULL) {
tmp_selectivity = 1.0;
if (1 == join_conditions.count()) {
// only one join condition, calculate selectivity directly
if (OB_ISNULL(join_conditions.at(0))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else if (OB_FAIL(get_equal_sel(table_metas, ctx, *join_conditions.at(0), tmp_selectivity))) {
LOG_WARN("Failed to get equal selectivity", K(ret));
} else {
LOG_PRINT_EXPR(TRACE, "get single equal expr selectivity", *join_conditions.at(0), K(tmp_selectivity));
}
} else if (join_conditions.count() > 1) {
// 存在多个连接条件，检查是否涉及联合主键
if (OB_FAIL(get_equal_sel(table_metas, ctx, join_conditions, tmp_selectivity))) {
LOG_WARN("failed to get equal sel");
} else {
LOG_TRACE("get multi equal expr selectivity", K(join_conditions), K(tmp_selectivity));
}
}
if (OB_SUCC(ret)) {
tmp_selectivity = revise_between_0_1(tmp_selectivity);
selectivity *= tmp_selectivity;
}
}
return ret;
}
int ObOptSelectivity::check_qual_later_calculation(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
ObRawExpr &qual,
ObIArray<ObExprSelPair> &all_pred_sel,
ObIArray<ObRawExpr *> &join_conditions,
ObIArray<RangeExprs> &range_conditions,
bool &need_skip)
{
int ret = OB_SUCCESS;
need_skip = false;
if (OB_FAIL(is_simple_join_condition(qual,
ctx.get_left_rel_ids(),
ctx.get_right_rel_ids(),
need_skip,
join_conditions))) {
LOG_WARN("failed to check is simple join condition", K(ret));
} else if (!need_skip && OB_FAIL(ObOptEstUtils::extract_simple_cond_filters(qual,
need_skip,
range_conditions))) {
LOG_WARN("failed to extract simple cond filters", K(ret));
} else if (need_skip) {
// calculate qual selectivity if qual not in all_predicate_sel
double tmp_sel = 1.0;
if (ObOptimizerUtil::find_item(all_pred_sel, ObExprSelPair(&qual, 0))) {
// do nothing
} else if (OB_FAIL(calculate_qual_selectivity(table_metas, ctx, qual, tmp_sel, all_pred_sel))) {
LOG_WARN("failed to calculate one qual selectivity", K(qual), K(ret));
}
}
return ret;
}
/**
* check if qual is a simple join condition.
* This recommend each side of `=` belong to different subtree.
*/
int ObOptSelectivity::is_simple_join_condition(ObRawExpr &qual,
const ObRelIds *left_rel_ids,
const ObRelIds *right_rel_ids,
bool &is_valid,
ObIArray<ObRawExpr *> &join_conditions)
{
int ret = OB_SUCCESS;
is_valid = false;
if (NULL == left_rel_ids || NULL == right_rel_ids) {
// do nothing
} else if (T_OP_EQ == qual.get_expr_type() || T_OP_NSEQ == qual.get_expr_type()) {
ObRawExpr *expr0 = qual.get_param_expr(0);
ObRawExpr *expr1 = qual.get_param_expr(1);
if (OB_ISNULL(expr0) || OB_ISNULL(expr1)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null exprs", K(ret), K(expr0), K(expr1));
} else if (OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(expr0, expr0)) ||
OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(expr1, expr1))) {
LOG_WARN("failed to get expr without lossless cast", K(ret));
} else if (!expr0->is_column_ref_expr() || !expr1->is_column_ref_expr()) {
// do nothing
} else if ((left_rel_ids->is_superset(expr0->get_relation_ids()) &&
right_rel_ids->is_superset(expr1->get_relation_ids())) ||
(left_rel_ids->is_superset(expr1->get_relation_ids()) &&
right_rel_ids->is_superset(expr0->get_relation_ids()))) {
if (OB_FAIL(join_conditions.push_back(&qual))) {
LOG_WARN("failed to push back expr", K(ret));
} else {
is_valid = true;
}
} else { /* do nothing */ }
}
return ret;
}
int ObOptSelectivity::calculate_qual_selectivity(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity,
ObIArray<ObExprSelPair> &all_predicate_sel)
{
int ret = OB_SUCCESS;
selectivity = 1.0;
if (qual.has_flag(CNT_AGG)) {
if (OB_FAIL(get_agg_sel(table_metas, ctx, qual, selectivity))) {
LOG_WARN("failed to get agg expr selectivity", K(ret), K(qual));
}
} else if (qual.is_const_expr()) {
if (OB_FAIL(get_const_sel(ctx, qual, selectivity))) {
LOG_WARN("failed to get const expr selectivity", K(ret), K(qual));
}
} else if (qual.is_column_ref_expr()) {
if (OB_FAIL(get_column_sel(table_metas, ctx, qual, selectivity))) {
LOG_WARN("failed to get column selectivity", K(ret), K(qual));
}
} else if (T_OP_EQ == qual.get_expr_type() || T_OP_NSEQ == qual.get_expr_type()) {
if (OB_FAIL(get_equal_sel(table_metas, ctx, qual, selectivity))) {
LOG_WARN("failed to get equal selectivity", K(ret));
}
} else if (T_OP_IN == qual.get_expr_type() || T_OP_NOT_IN == qual.get_expr_type()) {
if (OB_FAIL(get_in_sel(table_metas, ctx, qual, selectivity))) {
LOG_WARN("failed to get in selectivity", K(ret));
}
} else if (T_OP_IS == qual.get_expr_type() || T_OP_IS_NOT == qual.get_expr_type()) {
if (OB_FAIL(get_is_sel(table_metas, ctx, qual, selectivity))) {
LOG_WARN("failed to get is selectivity", K(ret));
}
} else if (IS_RANGE_CMP_OP(qual.get_expr_type())) {
if (OB_FAIL(get_range_cmp_sel(table_metas, ctx, qual, selectivity))) {
LOG_WARN("failed to get range cmp selectivity", K(ret));
}
} else if (T_OP_LIKE == qual.get_expr_type()) {
if (OB_FAIL(get_like_sel(table_metas, ctx, qual, selectivity))) {
LOG_WARN("failed to get like selectivity", K(ret));
}
} else if (T_OP_BTW == qual.get_expr_type() || T_OP_NOT_BTW == qual.get_expr_type()) {
if (OB_FAIL(get_btw_sel(table_metas, ctx, qual, selectivity))) {
LOG_WARN("failed to get between selectivity", K(ret));
}
} else if (T_OP_NOT == qual.get_expr_type()) {
if (OB_FAIL(get_not_sel(table_metas, ctx, qual, selectivity, all_predicate_sel))) {
LOG_WARN("failed to get not selectivity", K(ret));
}
} else if (T_OP_NE == qual.get_expr_type()) {
if (OB_FAIL(get_ne_sel(table_metas, ctx, qual, selectivity))) {
LOG_WARN("failed to get not selectivity", K(ret));
}
} else if (T_OP_AND == qual.get_expr_type()) {
double tmp_selectivity = 1.0;
for (int64_t i = 0; OB_SUCC(ret) && i < qual.get_param_count(); ++i) {
const ObRawExpr *child_expr = qual.get_param_expr(i);
if (OB_ISNULL(child_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret));
} else if (OB_FAIL(calculate_qual_selectivity(table_metas, ctx, *child_expr,
tmp_selectivity, all_predicate_sel))) {
LOG_WARN("failed to callculate one qual selectivity", K(child_expr), K(ret));
} else {
selectivity *= tmp_selectivity;
}
}
} else if (T_OP_OR == qual.get_expr_type()) {
double tmp_selectivity = 1.0;
selectivity = 0;
bool is_mutex = false;;
if (OB_FAIL(check_mutex_or(qual, is_mutex))) {
LOG_WARN("failed to check mutex or", K(ret));
} else {
for (int64_t i = 0; OB_SUCC(ret) && i < qual.get_param_count(); ++i) {
const ObRawExpr *child_expr = qual.get_param_expr(i);
if (OB_ISNULL(child_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret));
} else if (OB_FAIL(calculate_qual_selectivity(table_metas, ctx, *child_expr,
tmp_selectivity, all_predicate_sel))) {
LOG_WARN("failed to callculate one qual selectivity", K(child_expr), K(ret));
} else if (0 == i || is_mutex) {
selectivity += tmp_selectivity;
} else {
selectivity += tmp_selectivity - tmp_selectivity * selectivity;
}
}
}
} else if (qual.is_spatial_expr()) {
selectivity = DEFAULT_SPATIAL_SEL;
} else { //任何处理不了的表达式，都认为是0.5的选择率 } else { //任何处理不了的表达式，都认为是0.5的选择率
selectivity = DEFAULT_SEL;
}
if (OB_SUCC(ret)) {
LOG_PRINT_EXPR(TRACE, "calculate one qual selectivity", qual, K(selectivity));
// We remember each predicate's selectivity in the plan so that we can reorder them
// in the vector of filters according to their selectivity.
if (OB_FAIL(add_var_to_array_no_dup(all_predicate_sel, ObExprSelPair(&qual, selectivity)))) {
LOG_WARN("failed to add selectivity to plan", K(ret), K(qual), K(selectivity));
}
}
return ret;
}
int ObOptSelectivity::update_table_meta_info(const OptTableMetas &base_table_metas,
OptTableMetas &update_table_metas,
const OptSelectivityCtx &ctx,
const uint64_t table_id,
double filtered_rows,
const common::ObIArray<ObRawExpr*> &quals,
common::ObIArray<ObExprSelPair> &all_predicate_sel)
{
int ret = OB_SUCCESS;
const OptTableMeta *base_table_meta = base_table_metas.get_table_meta_by_table_id(table_id);
OptTableMeta *table_meta = NULL;
const ObLogPlan *log_plan = NULL;
ObSEArray<OptSelInfo, 8> column_sel_infos;
filtered_rows = filtered_rows < 1.0 ? 1.0 : filtered_rows;
if (OB_ISNULL(base_table_meta) || OB_ISNULL(log_plan = ctx.get_plan())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(base_table_meta), K(log_plan));
} else if (OB_FAIL(update_table_metas.copy_table_meta_info(*base_table_meta, table_meta))) {
LOG_WARN("failed to copy table meta info", K(ret));
} else {
double origin_rows = table_meta->get_rows();
table_meta->set_rows(filtered_rows);
if (filtered_rows >= origin_rows) {
// only update table rows
} else if (OB_FAIL(classify_quals(quals, all_predicate_sel, column_sel_infos))) {
LOG_WARN("failed to classify quals", K(ret));
} else {
for (int64_t i = 0; OB_SUCC(ret) && i < table_meta->get_column_metas().count(); ++i) {
OptColumnMeta &column_meta = table_meta->get_column_metas().at(i);
OptSelInfo *sel_info = NULL;
for (int64_t j = 0; NULL == sel_info && j < column_sel_infos.count(); ++j) {
if (column_sel_infos.at(j).column_id_ == column_meta.get_column_id()) {
sel_info = &column_sel_infos.at(j);
}
}
/**
* ndv的缩放分两步
* 第一步：
* 1. 如果存在某一列上的非复杂谓词，直接使用非复杂谓词计算该列第一步的ndv和rows
* 2. 如果某一列只有复杂谓词，则直接使用缩放公式计算该列第一步的ndv和rows
* 第二步：
* 使用第一步得到的ndv和rows作为column的原始ndv和rows，再基于所有过滤谓词过滤后的行数，
* 使用缩放公式缩放列的ndv。
*/
double step1_ndv = column_meta.get_ndv();
double step2_ndv = column_meta.get_ndv();
double step1_row = origin_rows;
double null_num = column_meta.get_num_null();
double hist_scale = -1;
// step 1
if (OB_NOT_NULL(sel_info)) {
step1_row *= sel_info->selectivity_;
hist_scale = sel_info->selectivity_;
if (sel_info->equal_count_ > 0) {
step1_ndv = sel_info->equal_count_;
} else if (sel_info->has_range_exprs_) {
step1_ndv *= sel_info->range_selectivity_;
} else {
step1_ndv = scale_distinct(step1_row, origin_rows, column_meta.get_ndv());
}
}
// step 2
if (filtered_rows < step1_row) {
step2_ndv = scale_distinct(filtered_rows, step1_row, step1_ndv);
} else {
step2_ndv = step1_ndv;
}
// update null number
if (null_num > 0) {
bool null_reject = false;
const ObColumnRefRawExpr *column_expr = log_plan->get_column_expr_by_id(
table_meta->get_table_id(), column_meta.get_column_id());
if (OB_ISNULL(column_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret), K(column_meta.get_column_id()));
} else if (OB_FAIL(ObTransformUtils::has_null_reject_condition(quals,
column_expr,
null_reject))) {
LOG_WARN("failed to check has null reject condition", K(ret));
} else if (null_reject) {
null_num = 0;
} else {
null_num = null_num * filtered_rows / origin_rows;
}
}
// set new column meta
if (OB_SUCC(ret)) {
column_meta.set_ndv(revise_ndv(step2_ndv));
column_meta.set_num_null(null_num);
column_meta.set_hist_scale(hist_scale);
}
}
}
}
LOG_TRACE("show table meta after update", KPC(table_meta));
return ret;
}
int ObOptSelectivity::get_const_sel(const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity)
{
int ret = OB_SUCCESS;
const ParamStore *params = ctx.get_params();
const ObDMLStmt *stmt = ctx.get_stmt();
if (OB_ISNULL(params) || OB_ISNULL(stmt)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(params), K(stmt));
} else if (ObOptEstUtils::is_calculable_expr(qual, params->count())) {
ObObj const_value;
bool got_result = false;
bool is_true = false;
if (OB_FAIL(ObSQLUtils::calc_const_or_calculable_expr(ctx.get_opt_ctx().get_exec_ctx(),
&qual,
const_value,
got_result,
ctx.get_allocator()))) {
LOG_WARN("failed to calc const or calculable expr", K(ret));
} else if (!got_result) {
selectivity = DEFAULT_SEL;
} else if (OB_FAIL(ObObjEvaluator::is_true(const_value, is_true))) {
LOG_WARN("failed to check is const value true", K(ret));
} else {
selectivity = is_true ? 1.0 : 0.0;
}
} else {
selectivity = DEFAULT_SEL;
}
return ret;
}
int ObOptSelectivity::get_column_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity)
{
int ret = OB_SUCCESS;
selectivity = DEFAULT_SEL;
double distinct_sel = 0.0;
double null_sel = 0.0;
if (!ob_is_string_or_lob_type(qual.get_data_type())) {
if (OB_FAIL(check_column_in_current_level_stmt(ctx.get_stmt(), qual))) {
LOG_WARN("Failed to check column in cur level stmt", K(ret));
} else if (OB_FAIL(get_column_basic_sel(table_metas, ctx, qual, &distinct_sel, &null_sel))) {
LOG_WARN("Failed to calc basic equal sel", K(ret));
} else {
selectivity = 1.0 - distinct_sel - null_sel;
}
}
return ret;
}
int ObOptSelectivity::get_equal_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity)
{
int ret = OB_SUCCESS;
const ObRawExpr *left_expr = qual.get_param_expr(0);
const ObRawExpr *right_expr = qual.get_param_expr(1);
if (OB_ISNULL(left_expr) || OB_ISNULL(right_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret), K(qual), K(left_expr), K(right_expr));
} else if (OB_FAIL(get_equal_sel(table_metas, ctx, *left_expr, *right_expr,
T_OP_NSEQ == qual.get_expr_type(), selectivity))) {
LOG_WARN("failed to get equal sel", K(ret));
}
return ret;
}
int ObOptSelectivity::get_equal_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &left_expr,
const ObRawExpr &right_expr,
const bool null_safe,
double &selectivity)
{
int ret = OB_SUCCESS;
if (T_OP_ROW == left_expr.get_expr_type() && T_OP_ROW == right_expr.get_expr_type()) {
// normally row equal row will unnest as `var = var and var = var ...`
selectivity = 1.0;
double tmp_selectivity = 1.0;
const ObRawExpr *l_expr = NULL;
const ObRawExpr *r_expr = NULL;
const ObRawExpr *l_row = &left_expr;
const ObRawExpr *r_row = &right_expr;
// (c1, c2) in ((const1, const2)) may transform to (c1, c2) = ((const1, const2))
if (left_expr.get_param_count() == 1 && OB_NOT_NULL(left_expr.get_param_expr(0)) &&
T_OP_ROW == left_expr.get_param_expr(0)->get_expr_type()) {
l_row = left_expr.get_param_expr(0);
}
if (right_expr.get_param_count() == 1 && OB_NOT_NULL(right_expr.get_param_expr(0)) &&
T_OP_ROW == right_expr.get_param_expr(0)->get_expr_type()) {
r_row = right_expr.get_param_expr(0);
}
if (OB_UNLIKELY(l_row->get_param_count() != r_row->get_param_count())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected expr", KPC(l_row), KPC(l_row), K(ret));
} else {
int64_t num = l_row->get_param_count();
for (int64_t i = 0; OB_SUCC(ret) && i < num; ++i) {
if (OB_ISNULL(l_expr = l_row->get_param_expr(i)) ||
OB_ISNULL(r_expr = r_row->get_param_expr(i))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret), K(l_expr), K(r_expr), K(i));
} else if (OB_FAIL(SMART_CALL(get_equal_sel(table_metas, ctx, *l_expr,
*r_expr, null_safe, tmp_selectivity)))) {
LOG_WARN("failed to get equal selectivity", K(ret));
} else {
selectivity *= tmp_selectivity;
}
}
}
} else if ((left_expr.has_flag(CNT_COLUMN) && !right_expr.has_flag(CNT_COLUMN)) ||
(!left_expr.has_flag(CNT_COLUMN) && right_expr.has_flag(CNT_COLUMN))) {
// column = const
const ObRawExpr *cnt_col_expr = left_expr.has_flag(CNT_COLUMN) ? &left_expr : &right_expr;
const ObRawExpr &calc_expr = left_expr.has_flag(CNT_COLUMN) ? right_expr : left_expr;
ObOptColumnStatHandle handler;
ObObj expr_value;
bool can_use_hist = false;
if (OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(cnt_col_expr, cnt_col_expr))) {
LOG_WARN("failed to get expr without lossless cast", K(ret));
} else if (cnt_col_expr->is_column_ref_expr()) {
const ObColumnRefRawExpr* col = static_cast<const ObColumnRefRawExpr*>(cnt_col_expr);
if (OB_FAIL(get_histogram_by_column(table_metas, ctx, col->get_table_id(),
col->get_column_id(), handler))) {
LOG_WARN("failed to get histogram by column", K(ret));
} else if (handler.stat_ == NULL || !handler.stat_->get_histogram().is_valid()) {
// do nothing
} else if (OB_FAIL(get_compare_value(ctx, col, &calc_expr, expr_value, can_use_hist))) {
// cast may failed due to invalid type or value out of range.
// Then use ndv instead of histogram
can_use_hist = false;
ret = OB_SUCCESS;
}
}
if (OB_SUCC(ret)) {
if (can_use_hist) {
double nns = 0;
double hist_scale = 0;
if (OB_FAIL(get_column_hist_scale(table_metas, ctx, *cnt_col_expr, hist_scale))) {
LOG_WARN("failed to get columnn hist sample scale", K(ret));
} else if (OB_FAIL(get_equal_pred_sel(handler.stat_->get_histogram(), expr_value,
hist_scale, selectivity))) {
LOG_WARN("Failed to get equal density", K(ret));
} else if (OB_FAIL(get_column_ndv_and_nns(table_metas, ctx, *cnt_col_expr, NULL, &nns))) {
LOG_WARN("failed to get column ndv and nns", K(ret));
} else {
selectivity *= nns;
}
} else if (OB_FAIL(get_simple_equal_sel(table_metas, ctx, *cnt_col_expr,
&calc_expr, null_safe, selectivity))) {
LOG_WARN("failed to get simple equal selectivity", K(ret));
}
LOG_TRACE("succeed to get equal predicate sel", K(can_use_hist), K(selectivity));
}
} else if (left_expr.has_flag(CNT_COLUMN) && right_expr.has_flag(CNT_COLUMN)) {
if (OB_FAIL(get_cntcol_op_cntcol_sel(table_metas, ctx, left_expr, right_expr,
null_safe ? T_OP_NSEQ : T_OP_EQ, selectivity))) {
LOG_WARN("failed to get contain column equal contain column selectivity", K(ret));
} else {
LOG_TRACE("succeed to get contain column equal contain column sel", K(selectivity), K(ret));
}
} else {
// CONST_PARAM = CONST_PARAM
const ParamStore *params = ctx.get_params();
if (OB_ISNULL(params)) {
ret = OB_INVALID_ARGUMENT;
LOG_WARN("Params is NULL", K(ret));
} else if (ObOptEstUtils::is_calculable_expr(left_expr, params->count()) &&
ObOptEstUtils::is_calculable_expr(right_expr, params->count())) {
// 1 in (c1, 2, 3) will reach this branch
bool equal = false;
if (OB_FAIL(ObOptEstUtils::if_expr_value_equal(const_cast<ObOptimizerContext &>(ctx.get_opt_ctx()),
ctx.get_stmt(),
left_expr, right_expr, null_safe, equal))) {
LOG_WARN("Failed to check hvae equal expr", K(ret));
} else {
selectivity = equal ? 1.0 : 0.0;
}
} else {
selectivity = DEFAULT_EQ_SEL;
}
}
return ret;
}
int ObOptSelectivity::get_simple_equal_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &cnt_col_expr,
const ObRawExpr *calculable_expr,
const bool null_safe,
double &selectivity)
{
int ret = OB_SUCCESS;
ObSEArray<const ObColumnRefRawExpr*, 2> column_exprs;
bool only_monotonic_op = true;
const ObColumnRefRawExpr *column_expr = NULL;
double distinct_sel = 1.0;
double null_sel = 1.0;
bool is_null_value = false;
if (OB_FAIL(ObOptEstUtils::extract_column_exprs_with_op_check(&cnt_col_expr,
column_exprs,
only_monotonic_op))) {
LOG_WARN("failed to extract column exprs with op check", K(ret));
} else if (!only_monotonic_op || column_exprs.count() > 1) {
// cnt_col_expr contain not monotonic op OR has more than 1 column
selectivity = DEFAULT_EQ_SEL;
} else if (OB_UNLIKELY(1 != column_exprs.count()) ||
OB_ISNULL(column_expr = column_exprs.at(0))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpect column expr", K(column_exprs), K(cnt_col_expr), K(column_expr));
} else if (OB_FAIL(get_column_basic_sel(table_metas, ctx, *column_expr,
&distinct_sel, &null_sel))) {
LOG_WARN("failed to get column basic selelectivity", K(ret));
} else if (NULL == calculable_expr) {
selectivity = distinct_sel;
} else if (OB_FAIL(ObOptEstUtils::if_expr_value_null(ctx.get_params(),
*calculable_expr,
ctx.get_opt_ctx().get_exec_ctx(),
ctx.get_allocator(),
is_null_value))) {
LOG_WARN("failed to check if expr value null", K(ret));
} else if (!is_null_value) {
selectivity = distinct_sel;
} else if (null_safe) {
selectivity = null_sel;
} else {
selectivity = 0.0;
}
return ret;
}
int ObOptSelectivity::get_cntcol_op_cntcol_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &input_left_expr,
const ObRawExpr &input_right_expr,
ObItemType op_type,
double &selectivity)
{
int ret = OB_SUCCESS;
double left_ndv = 1.0;
double right_ndv = 1.0;
double left_nns = 0.0;
double right_nns = 0.0;
selectivity = DEFAULT_EQ_SEL;
const ObRawExpr* left_expr = &input_left_expr;
const ObRawExpr* right_expr = &input_right_expr;
if (OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(left_expr, left_expr)) ||
OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(right_expr, right_expr))) {
LOG_WARN("failed to check is lossless column cast", K(ret));
} else if (OB_ISNULL(left_expr) || OB_ISNULL(right_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(left_expr), K(right_expr));
} else if (left_expr->is_column_ref_expr() && right_expr->is_column_ref_expr()) {
const ObColumnRefRawExpr* left_col = NULL;
const ObColumnRefRawExpr* right_col = NULL;
if (OB_FAIL(filter_one_column_by_equal_set(table_metas, ctx, left_expr, left_expr))) {
LOG_WARN("failed filter column by equal set", K(ret));
} else if (OB_FAIL(filter_one_column_by_equal_set(table_metas, ctx, right_expr, right_expr))) {
LOG_WARN("failed filter column by equal set", K(ret));
} else if (OB_FAIL(get_column_ndv_and_nns(table_metas, ctx, *left_expr, &left_ndv, &left_nns))) {
LOG_WARN("failed to get column basic sel", K(ret));
} else if (OB_FAIL(get_column_ndv_and_nns(table_metas, ctx, *right_expr,
&right_ndv, &right_nns))) {
LOG_WARN("failed to get column basic sel", K(ret));
} else if (FALSE_IT(left_col = static_cast<const ObColumnRefRawExpr*>(left_expr)) ||
FALSE_IT(right_col = static_cast<const ObColumnRefRawExpr*>(right_expr))) {
// never reach
} else if (left_expr->get_relation_ids() == right_expr->get_relation_ids()) {
if (left_col->get_column_id() == right_col->get_column_id()) {
// same table same column
if (T_OP_NSEQ == op_type) {
selectivity = 1.0;
} else if (T_OP_EQ == op_type) {
selectivity = left_nns;
} else if (T_OP_NE == op_type) {
selectivity = 0.0;
}
} else {
//same table different column
if (T_OP_NSEQ == op_type) {
selectivity = left_nns * right_nns / std::max(left_ndv, right_ndv)
+ (1 - left_nns) * (1 - right_nns);
} else if (T_OP_EQ == op_type) {
selectivity = left_nns * right_nns / std::max(left_ndv, right_ndv);
} else if (T_OP_NE == op_type) {
selectivity = left_nns * right_nns * (1 - 1/std::max(left_ndv, right_ndv));
}
}
} else {
// different table
ObOptColumnStatHandle left_handler;
ObOptColumnStatHandle right_handler;
obj_cmp_func cmp_func = NULL;
bool calc_with_hist = false;
if (!ObObjCmpFuncs::can_cmp_without_cast(left_col->get_result_type(),
right_col->get_result_type(),
CO_EQ, cmp_func)) {
// do nothing
} else if (OB_FAIL(get_histogram_by_column(table_metas, ctx, left_col->get_table_id(),
left_col->get_column_id(), left_handler))) {
LOG_WARN("failed to get histogram by column", K(ret));
} else if (OB_FAIL(get_histogram_by_column(table_metas, ctx, right_col->get_table_id(),
right_col->get_column_id(), right_handler))) {
LOG_WARN("failed to get histogram by column", K(ret));
} else if (left_handler.stat_ != NULL && right_handler.stat_ != NULL &&
left_handler.stat_->get_histogram().is_frequency() &&
right_handler.stat_->get_histogram().is_frequency()) {
calc_with_hist = true;
}
if (OB_FAIL(ret)) {
} else if (IS_SEMI_ANTI_JOIN(ctx.get_join_type())) {
if (OB_ISNULL(ctx.get_left_rel_ids()) || OB_ISNULL(ctx.get_right_rel_ids())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ctx.get_left_rel_ids()), K(ctx.get_right_rel_ids()));
} else if (left_expr->get_relation_ids().overlap(*ctx.get_right_rel_ids()) ||
right_expr->get_relation_ids().overlap(*ctx.get_left_rel_ids())) {
std::swap(left_ndv, right_ndv);
std::swap(left_nns, right_nns);
}
if (OB_SUCC(ret)) {
if (calc_with_hist) {
double total_rows = 0;
double left_rows = 0;
double left_null = 0;
double right_rows = 0;
double right_null = 0;
if (OB_FAIL(get_join_pred_rows(left_handler.stat_->get_histogram(),
right_handler.stat_->get_histogram(),
true, total_rows))) {
LOG_WARN("failed to get join pred rows", K(ret));
} else if (OB_FAIL(get_column_basic_info(ctx.get_plan()->get_basic_table_metas(), ctx,
*left_expr, NULL, &left_null, NULL, &left_rows))) {
LOG_WARN("failed to get column basic info", K(ret));
} else if (OB_FAIL(get_column_basic_info(ctx.get_plan()->get_basic_table_metas(), ctx,
*right_expr, NULL, &right_null, NULL, &right_rows))) {
LOG_WARN("failed to get column basic info", K(ret));
} else if (T_OP_NSEQ == op_type) {
total_rows += right_null > 0 ? left_null : 0;
selectivity = total_rows / left_rows;
} else if (T_OP_EQ == op_type) {
selectivity = total_rows / left_rows;
} else if (T_OP_NE == op_type) {
selectivity = ((left_rows - left_null) * (right_rows - right_null) - total_rows)
/ left_rows / right_rows;
}
} else {
/**
* ## non NULL safe
* a) semi: `(min(ndv1, ndv2) / ndv1) * (1.0 - nullfrac1)`
* ## NULL safe
* a) semi: `(min(ndv1, ndv2) / ndv1) * (1.0 - nullfrac1) + nullfrac2 > 0 && nullsafe ? nullfrac1: 0`
*/
if (IS_LEFT_SEMI_ANTI_JOIN(ctx.get_join_type())) {
if (T_OP_NSEQ == op_type) {
selectivity = (std::min(left_ndv, right_ndv) / left_ndv) * left_nns;
if (1 - right_nns > 0) {
selectivity += (1 - left_nns);
}
} else if (T_OP_EQ == op_type) {
selectivity = (std::min(left_ndv, right_ndv) / left_ndv) * left_nns;
} else if (T_OP_NE == op_type) {
if (right_ndv > 1.0) {
// if right ndv > 1.0, then there must exist one value not equal to left value
selectivity = left_nns;
} else {
selectivity = (1 - 1 / left_ndv) * left_nns;
}
}
} else {
if (T_OP_NSEQ == op_type) {
selectivity = (std::min(left_ndv, right_ndv) / right_ndv) * right_nns;
if (1 - left_nns > 0) {
selectivity += (1 - right_nns);
}
} else if (T_OP_EQ == op_type) {
selectivity = (std::min(left_ndv, right_ndv) / right_ndv) * right_nns;
} else if (T_OP_NE == op_type) {
if (left_ndv > 1.0) {
// if left ndv > 1.0, then there must exist one value not equal to right value
selectivity = right_nns;
} else {
selectivity = (1 - 1 / right_ndv) * right_nns;
}
}
}
}
}
if (OB_SUCC(ret) && selectivity >= 1.0 && IS_ANTI_JOIN(ctx.get_join_type())) {
selectivity = 1 - DEFAULT_ANTI_JOIN_SEL;
}
} else {
// inner join, outer join
if (calc_with_hist) {
// use frequency histogram calculate selectivity
double total_rows = 0;
double left_rows = 0;
double left_null = 0;
double right_rows = 0;
double right_null = 0;
if (OB_FAIL(get_join_pred_rows(left_handler.stat_->get_histogram(),
right_handler.stat_->get_histogram(),
false, total_rows))) {
LOG_WARN("failed to get join pred rows", K(ret));
} else if (OB_FAIL(get_column_basic_info(ctx.get_plan()->get_basic_table_metas(), ctx,
*left_expr, NULL, &left_null, NULL, &left_rows))) {
LOG_WARN("failed to get column basic info", K(ret));
} else if (OB_FAIL(get_column_basic_info(ctx.get_plan()->get_basic_table_metas(), ctx,
*right_expr, NULL, &right_null, NULL, &right_rows))) {
LOG_WARN("failed to get column basic info", K(ret));
} else if (T_OP_NSEQ == op_type) {
selectivity = (total_rows + left_null * right_null) / left_rows / right_rows;
} else if (T_OP_EQ == op_type) {
selectivity = total_rows / left_rows / right_rows;
} else if (T_OP_NE == op_type) {
selectivity = ((left_rows - left_null) * (right_rows - right_null) - total_rows)
/ left_rows / right_rows;
}
} else {
/**
* ## non NULL safe
* (1.0 - nullfrac1) * (1.0 - nullfrac2) / MAX(nd1, nd2)
* ## NULL safe
* (1.0 - nullfrac1) * (1.0 - nullfrac2) / MAX(nd1, nd2) + nullfraf1 * nullfrac2
* 目前不会特殊考虑 outer join 的选择率, 而是在外层对行数进行 revise.
*/
if (T_OP_NSEQ == op_type) {
selectivity = left_nns * right_nns / std::max(left_ndv, right_ndv)
+ (1 - left_nns) * (1 - right_nns);
} else if (T_OP_EQ == op_type) {
selectivity = left_nns * right_nns / std::max(left_ndv, right_ndv);
} else if (T_OP_NE == op_type) {
selectivity = left_nns * right_nns * (1 - 1/std::max(left_ndv, right_ndv));
}
}
}
}
} else if (left_expr->is_column_ref_expr() || right_expr->is_column_ref_expr()) {
// col1 = func(col2), selectivity is 1 / ndv(col1)
// inner join and semi join use same formula
/**
* some test with generated table in oracle:
* select * from t1,t2,(select c1 as agg from t3) v where t1.c1 + t2.c1 = v.agg;
* => sel(t1.c1 + t2.c1 = v.agg) = 1/ndv(v.agg)
* select * from t1,t2,(select c1+c2 as agg from t3) v where t1.c1 + t2.c1 = v.agg;
* => sel(t1.c1 + t2.c1 = v.agg) = 1/100
* select * from t1,t2,(select max(c1) as agg from t3) v where t1.c1 + t2.c1 = v.agg;
* => sel(t1.c1 + t2.c1 = v.agg) = 1/100
* it seems like in oracle, if an equal condition is `col1 = fun(cols)` and col1 is from a
* generated table. oracle will check whether col1 is refered a basic column. If not, use
* default
*/
const ObRawExpr* column_expr = left_expr->is_column_ref_expr() ? left_expr : right_expr;
if (OB_FAIL(get_column_basic_sel(table_metas, ctx, *column_expr, &selectivity))) {
LOG_WARN("failed to get column basic selelectivity", K(ret));
} else if (T_OP_NE == op_type) {
selectivity = 1 - selectivity;
}
} else {
// func(col) = func(col)
double left_sel = 0.0;
double right_sel = 0.0;
if (OB_FAIL(get_simple_equal_sel(table_metas, ctx, *left_expr, NULL,
T_OP_NSEQ == op_type, left_sel))) {
LOG_WARN("Failed to get simple predicate sel", K(ret));
} else if (OB_FAIL(get_simple_equal_sel(table_metas, ctx, *right_expr, NULL,
T_OP_NSEQ == op_type, right_sel))) {
LOG_WARN("Failed to get simple predicate sel", K(ret));
} else {
selectivity = std::min(left_sel, right_sel);
if (T_OP_NE == op_type) {
selectivity = 1 - selectivity;
}
}
}
return ret;
}
int ObOptSelectivity::get_equal_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
ObIArray<ObRawExpr *> &quals,
double &selectivity)
{
int ret = OB_SUCCESS;
ObSEArray<ObRawExpr *, 4> left_exprs;
ObSEArray<ObRawExpr *, 4> right_exprs;
ObSEArray<bool, 4> null_safes;
bool is_valid;
if (OB_ISNULL(ctx.get_left_rel_ids()) || OB_ISNULL(ctx.get_right_rel_ids())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("failed get unexpected null", K(ret), K(ctx));
} else if (OB_FAIL(is_valid_multi_join(quals, is_valid))) {
LOG_WARN("failed to check is valid multi join", K(ret));
} else if (!is_valid) {
// multi join condition related to more than two table. Calculate selectivity for each join
// condition independently.
for (int64_t i = 0; OB_SUCC(ret) && i < quals.count(); ++i) {
ObRawExpr *cur_expr = quals.at(i);
double tmp_sel = 1.0;
if (OB_ISNULL(cur_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else if (OB_FAIL(get_equal_sel(table_metas, ctx, *cur_expr, tmp_sel))) {
LOG_WARN("failed to get equal selectivity", K(ret));
} else {
selectivity *= tmp_sel;
}
}
} else if (OB_FAIL(extract_join_exprs(quals, *ctx.get_left_rel_ids(), *ctx.get_right_rel_ids(),
left_exprs, right_exprs, null_safes))) {
LOG_WARN("failed to extract join exprs", K(ret));
} else if (OB_FAIL(get_cntcols_eq_cntcols_sel(table_metas, ctx, left_exprs, right_exprs,
null_safes, selectivity))) {
LOG_WARN("Failed to get equal sel", K(ret));
} else { /* do nothing */ }
return ret;
}
int ObOptSelectivity::extract_join_exprs(ObIArray<ObRawExpr *> &quals,
const ObRelIds &left_rel_ids,
const ObRelIds &right_rel_ids,
ObIArray<ObRawExpr *> &left_exprs,
ObIArray<ObRawExpr *> &right_exprs,
ObIArray<bool> &null_safes)
{
int ret = OB_SUCCESS;
ObRawExpr *left_expr = NULL;
ObRawExpr *right_expr = NULL;
for (int64_t i = 0; OB_SUCC(ret) && i < quals.count(); ++i) {
ObRawExpr *cur_expr = quals.at(i);
if (OB_ISNULL(cur_expr) ||
OB_ISNULL(left_expr = cur_expr->get_param_expr(0)) ||
OB_ISNULL(right_expr = cur_expr->get_param_expr(1))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(cur_expr), K(left_expr), K(right_expr));
} else if (OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(left_expr, left_expr)) ||
OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(right_expr, right_expr))) {
LOG_WARN("failed to get expr without lossless cast", K(ret));
} else if (OB_UNLIKELY(!left_expr->is_column_ref_expr() || !right_expr->is_column_ref_expr())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("all expr should be column ref", K(ret), K(*cur_expr));
} else if (left_rel_ids.is_superset(left_expr->get_relation_ids()) &&
right_rel_ids.is_superset(right_expr->get_relation_ids())) {
// do nothing
} else if (left_rel_ids.is_superset(right_expr->get_relation_ids()) &&
right_rel_ids.is_superset(left_expr->get_relation_ids())) {
std::swap(left_expr, right_expr);
} else {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected expr", K(ret), K(left_expr), K(right_expr));
}
if (OB_SUCC(ret)) {
if (OB_FAIL(left_exprs.push_back(left_expr))) {
LOG_WARN("failed to push back expr", K(ret));
} else if (OB_FAIL(right_exprs.push_back(right_expr))) {
LOG_WARN("failed to push back expr", K(ret));
} else if (OB_FAIL(null_safes.push_back(T_OP_NSEQ == cur_expr->get_expr_type()))) {
LOG_WARN("failed to push back null safe", K(ret));
}
}
}
return ret;
}
int ObOptSelectivity::get_cntcols_eq_cntcols_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObIArray<ObRawExpr *> &left_exprs,
const ObIArray<ObRawExpr *> &right_exprs,
const ObIArray<bool> &null_safes,
double &selectivity)
{
int ret = OB_SUCCESS;
selectivity = DEFAULT_EQ_SEL;
ObSEArray<double, 4> left_ndvs;
ObSEArray<double, 4> right_ndvs;
ObSEArray<double, 4> left_not_null_sels;
ObSEArray<double, 4> right_not_null_sels;
double left_ndv = 1.0;
double right_ndv = 1.0;
double left_nns = 1.0;
double right_nns = 1.0;
double left_rows = 1.0;
double right_rows = 1.0;
double left_origin_rows = 1.0;
double right_origin_rows = 1.0;
bool left_contain_pk = false;
bool right_contain_pk = false;
bool is_union_pk = false;
bool refine_right_ndv = false;
bool refine_left_ndv = false;
if (OB_ISNULL(ctx.get_plan())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else if (OB_FAIL(is_columns_contain_pkey(table_metas, left_exprs,
left_contain_pk, is_union_pk))) {
LOG_WARN("failed to check is columns contain pkey", K(ret));
} else if (OB_FALSE_IT(refine_right_ndv = left_contain_pk && is_union_pk)) {
} else if (OB_FAIL(is_columns_contain_pkey(table_metas, right_exprs,
right_contain_pk, is_union_pk))) {
LOG_WARN("failed to check is columns contain pkey", K(ret));
} else if (OB_FALSE_IT(refine_left_ndv = right_contain_pk && is_union_pk)) {
} else {
for (int64_t i = 0; OB_SUCC(ret) && i < left_exprs.count(); ++i) {
if (OB_ISNULL(left_exprs.at(i)) || OB_ISNULL(right_exprs.at(i))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else if (OB_FAIL(get_column_ndv_and_nns(table_metas, ctx, *left_exprs.at(i),
&left_ndv, &left_nns))) {
LOG_WARN("failed to get left ndv and nns", K(ret));
} else if (OB_FAIL(get_column_ndv_and_nns(table_metas, ctx, *right_exprs.at(i),
&right_ndv, &right_nns))) {
LOG_WARN("failed to get left ndv and nns", K(ret));
} else if (OB_FAIL(left_not_null_sels.push_back(left_nns))) {
LOG_WARN("failed to push back not null sel", K(ret));
} else if (OB_FAIL(right_not_null_sels.push_back(right_nns))) {
LOG_WARN("failed to push back not null sel", K(ret));
} else if (OB_FAIL(left_ndvs.push_back(left_ndv))) {
LOG_WARN("failed to push back ndv", K(ret));
} else if (OB_FAIL(right_ndvs.push_back(right_ndv))) {
LOG_WARN("failed to push back ndv", K(ret));
} else if (0 == i) {
if (OB_FAIL(get_column_basic_info(table_metas, ctx, *left_exprs.at(i),
NULL, NULL, NULL, &left_rows))) {
LOG_WARN("failed to get column basic info", K(ret));
} else if (OB_FAIL(get_column_basic_info(table_metas, ctx, *right_exprs.at(i),
NULL, NULL, NULL, &right_rows))) {
LOG_WARN("failed to get column basic info", K(ret));
} else if (refine_right_ndv &&
OB_FAIL(get_column_basic_info(ctx.get_plan()->get_basic_table_metas(),
ctx, *left_exprs.at(i),
NULL, NULL, NULL, &left_origin_rows))) {
LOG_WARN("failed to get column basic info", K(ret));
} else if (refine_left_ndv &&
OB_FAIL(get_column_basic_info(ctx.get_plan()->get_basic_table_metas(),
ctx, *right_exprs.at(i),
NULL, NULL, NULL, &right_origin_rows))) {
LOG_WARN("failed to get column basic info", K(ret));
}
}
}
}
if (OB_FAIL(ret)) {
} else if (OB_FAIL(calculate_distinct(table_metas, ctx, left_exprs, left_rows, left_ndv))) {
LOG_WARN("Failed to calculate distinct", K(ret));
} else if (OB_FAIL(calculate_distinct(table_metas, ctx, right_exprs, right_rows, right_ndv))) {
LOG_WARN("Failed to calculate distinct", K(ret));
} else if (IS_SEMI_ANTI_JOIN(ctx.get_join_type())) {
/**
* 对于 semi anti join, 选择率描述的是外表行数为基础的选择率
* # FORMULA
* ## non NULL safe
* a) semi: `(min(left_ndv, right_ndv) / left_ndv) * left_not_null_sel(i)`
* ## NULL safe
* a) semi: non NULL safe selectivity + `nullsafe(i) && left_not_null_sel(i) < 1.0 ? null_sel(i) * selectivity(j) [where j != i]: 0`
*/
if (IS_LEFT_SEMI_ANTI_JOIN(ctx.get_join_type())) {
selectivity = std::min(left_ndv, right_ndv) / left_ndv;
for (int64_t i = 0; i < left_not_null_sels.count(); ++i) {
selectivity *= left_not_null_sels.at(i);
}
// 处理 null safe，这里假设多列上同时为null即小概率事件，只考虑特定列上为null的情况
for (int64_t i = 0; i < null_safes.count(); ++i) {
if (OB_UNLIKELY(null_safes.at(i) && right_not_null_sels.at(i) < 1.0)) {
double factor = 1.0;
for (int64_t j = 0; j < null_safes.count(); ++j) {
if (i == j) {
factor *= (1 - left_not_null_sels.at(j));
} else {
factor *= left_not_null_sels.at(j) * std::min(left_ndvs.at(j), right_ndvs.at(j)) / left_ndvs.at(j);
}
}
selectivity += factor;
}
}
} else {
selectivity = std::min(left_ndv, right_ndv) / right_ndv;
for (int64_t i = 0; i < right_not_null_sels.count(); ++i) {
selectivity *= right_not_null_sels.at(i);
}
// 处理 null safe，这里假设多列上同时为null即小概率事件，只考虑特定列上为null的情况
for (int64_t i = 0; i < null_safes.count(); ++i) {
if (OB_UNLIKELY(null_safes.at(i) && right_not_null_sels.at(i) < 1.0)) {
double factor = 1.0;
for (int64_t j = 0; j < null_safes.count(); ++j) {
if (i == j) {
factor *= (1 - right_not_null_sels.at(j));
} else {
factor *= right_not_null_sels.at(j) * std::min(left_ndvs.at(j), right_ndvs.at(j)) / right_ndvs.at(j);
}
}
selectivity += factor;
}
}
}
} else {
/**
* # FORMULA
* ## non NULL safe
* 1 / MAX(ndv1, ndv2) * not_null_frac1_col1 * not_null_frac2_col1 * not_null_frac1_col2 * not_null_frac2_col2 * ...
* ## NULL safe
* non NULL safe selectivity + `nullsafe(i) ? (1 - not_null_frac1_col(i)) * (1 - not_null_frac2_col(i)) * selectivity(col(j)) [where j != i]: 0`
* 目前不会特殊考虑 outer join 的选择率, 而是在外层对行数进行 revise.
*/
if (left_contain_pk == right_contain_pk) {
// 两侧都不是主键或都是主键, 不做修正
} else if (refine_right_ndv) {
// 一侧有主键时, 认为是主外键连接, 外键上最大的ndv为即为主键的原始ndv
right_ndv = std::min(right_ndv, left_origin_rows);
} else if (refine_left_ndv) {
left_ndv = std::min(left_ndv, right_origin_rows);
} else {
// do nothing
}
selectivity = 1.0 / std::max(left_ndv, right_ndv);
for (int64_t i = 0; i < left_not_null_sels.count(); ++i) {
selectivity *= left_not_null_sels.at(i) * right_not_null_sels.at(i);
}
// 处理null safe, 这里假设多列上同时为null即小概率事件，只考虑特定列上为null的情况
for (int64_t i = 0; i < null_safes.count(); ++i) {
if (null_safes.at(i)) {
double factor = 1.0;
for (int64_t j = 0; j < null_safes.count(); ++j) {
if (i == j) {
factor *= (1 - left_not_null_sels.at(j)) * (1 - right_not_null_sels.at(j));
} else {
factor *= left_not_null_sels.at(j) * right_not_null_sels.at(j) / std::max(left_ndvs.at(j), right_ndvs.at(j));
}
}
selectivity += factor;
} else {/* do nothing */}
}
}
LOG_TRACE("selectivity of `col_ref1 =|<=> col_ref1 and col_ref2 =|<=> col_ref2`", K(selectivity));
return ret;
}
/**
* 计算equal join condition的左右表选择率
* left_selectivity = right_ndv / left_ndv
* right_selectivity = left_ndv / right_ndv
* 如果left_rows > 0表示需要缩放左表的NDV
* 如果right_rows > 0表示需要缩放右表的NDV
*/
int ObOptSelectivity::calc_sel_for_equal_join_cond(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObIArray<ObRawExpr *>& conds,
const ObRelIds &left_ids,
double &left_selectivity,
double &right_selectivity)
{
int ret = OB_SUCCESS;
double left_ndv = 1.0;
double right_ndv = 1.0;
double tmp_ndv = 1.0;
double rows = 1.0;
const ObRawExpr *left = NULL;
const ObRawExpr *right = NULL;
for (int64_t i = 0; OB_SUCC(ret) && i < conds.count(); ++i) {
const ObRawExpr *expr = conds.at(i);
if (OB_ISNULL(expr) || OB_UNLIKELY(!expr->has_flag(IS_JOIN_COND))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected condition", KPC(expr), K(i), K(ret));
} else if (2 != expr->get_param_count() ||
OB_ISNULL(left = expr->get_param_expr(0)) ||
OB_ISNULL(right = expr->get_param_expr(1))) {
ret = OB_INVALID_ARGUMENT;
LOG_WARN("Invalid argument", K(ret));
} else if (OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(left, left)) ||
OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(right, right))) {
LOG_WARN("failed to get expr without lossless cast", K(ret));
} else {
if (!left->get_relation_ids().is_subset(left_ids)) {
std::swap(left, right);
}
if (!left->is_column_ref_expr()) {
left_ndv *= 1 / DEFAULT_EQ_SEL;
} else if (OB_FAIL(get_column_basic_info(table_metas, ctx, *left, &tmp_ndv, NULL, NULL, &rows))) {
LOG_WARN("failed to get column basic info", K(ret));
} else {
if (ctx.get_row_count_1() > 0.0 && ctx.get_row_count_1() < rows) {
tmp_ndv = scale_distinct(ctx.get_row_count_1(), rows, tmp_ndv);
}
left_ndv *= tmp_ndv;
}
if (OB_FAIL(ret)) {
//do nothing
} else if (!right->is_column_ref_expr()) {
right_ndv *= 1 / DEFAULT_EQ_SEL;
} else if (OB_FAIL(get_column_basic_info(table_metas, ctx, *right, &tmp_ndv, NULL, NULL, &rows))) {
LOG_WARN("failed to get column basic info", K(ret));
} else {
if (ctx.get_row_count_2() > 0.0 && ctx.get_row_count_2() < rows) {
tmp_ndv = scale_distinct(ctx.get_row_count_2(), rows, tmp_ndv);
}
right_ndv *= tmp_ndv;
}
}
}
if (OB_SUCC(ret)) {
left_selectivity = right_ndv / left_ndv;
right_selectivity = left_ndv / right_ndv;
left_selectivity = revise_between_0_1(left_selectivity);
right_selectivity = revise_between_0_1(right_selectivity);
}
return ret;
}
int ObOptSelectivity::get_in_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity)
{
int ret = OB_SUCCESS;
selectivity = 0.0;
double tmp_selectivity = 1.0;
double distinct_sel = 1.0;
double null_sel = 0.0;
const ObRawExpr *left_expr = NULL;
const ObRawExpr *right_expr = NULL;
const ObRawExpr *param_expr = NULL;
bool contain_null = false;
if (OB_UNLIKELY(2 != qual.get_param_count()) ||
OB_ISNULL(left_expr = qual.get_param_expr(0)) ||
OB_ISNULL(right_expr = qual.get_param_expr(1)) ||
T_OP_ROW != right_expr->get_expr_type()) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpect expr", K(ret), K(qual), K(left_expr), K(right_expr));
} else if (OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(left_expr, left_expr))) {
LOG_WARN("failed to get expr without lossless cast", K(ret));
} else if (OB_LIKELY(left_expr->is_column_ref_expr() && !right_expr->has_flag(CNT_COLUMN))) {
ObOptColumnStatHandle handler;
ObObj expr_value;
bool histogram_valid = false;
const ObColumnRefRawExpr *col = static_cast<const ObColumnRefRawExpr *>(left_expr);
hash::ObHashSet<ObObj> obj_set;
double hist_scale = 0;
if (OB_FAIL(obj_set.create(hash::cal_next_prime(right_expr->get_param_count()),
"OptSelHashSet", "OptSelHashSet"))) {
LOG_WARN("failed to create hash set", K(ret), K(right_expr->get_param_count()));
} else if (OB_FAIL(get_column_basic_sel(table_metas, ctx, *left_expr, &distinct_sel, &null_sel))) {
LOG_WARN("failed to get column basic selectivity", K(ret));
} else if (OB_FAIL(get_column_hist_scale(table_metas, ctx, *left_expr, hist_scale))) {
LOG_WARN("failed to get columnn hist sample scale", K(ret));
} else if (OB_FAIL(get_histogram_by_column(table_metas, ctx,
col->get_table_id(),
col->get_column_id(),
handler))) {
LOG_WARN("failed to get histogram by column", K(ret));
} else if (handler.stat_ != NULL && handler.stat_->get_histogram().is_valid()) {
histogram_valid = true;
}
for (int64_t i = 0; OB_SUCC(ret) && i < right_expr->get_param_count(); ++i) {
// bool can_use_hist = false;
bool get_value = false;
if (OB_ISNULL(param_expr = right_expr->get_param_expr(i))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret));
} else if (OB_FAIL(get_compare_value(ctx, col, param_expr, expr_value, get_value))) {
// cast may failed due to invalid type or value out of range.
// Then use ndv instead of histogram
get_value = false;
ret = OB_SUCCESS;
}
if (OB_SUCC(ret)) {
if (histogram_valid && get_value) {
double null_sel = 0;
if (OB_HASH_EXIST == obj_set.exist_refactored(expr_value)) {
// duplicate value, do nothing
} else if (OB_FAIL(obj_set.set_refactored(expr_value))) {
LOG_WARN("failed to set refactorcd", K(ret), K(expr_value));
} else if (OB_FAIL(get_equal_pred_sel(handler.stat_->get_histogram(),
expr_value,
hist_scale,
tmp_selectivity))) {
LOG_WARN("failed to get equal density", K(ret));
} else {
selectivity += tmp_selectivity * (1 - null_sel);
}
} else if (!get_value) {
// invalid value, for example c1 in (exec_param). Do not check obj exists.
if (param_expr->get_result_type().is_null()) {
contain_null = true;
} else {
selectivity += distinct_sel;
}
} else if (OB_HASH_EXIST == obj_set.exist_refactored(expr_value)) {
// do nothing
} else if (OB_FAIL(obj_set.set_refactored(expr_value))) {
LOG_WARN("failed to set refactorcd", K(ret), K(expr_value));
} else if (expr_value.is_null()) {
contain_null = true;
} else {
selectivity += distinct_sel;
}
}
}
if (obj_set.created()) {
int tmp_ret = OB_SUCCESS;
if (OB_SUCCESS != (tmp_ret = obj_set.destroy())) {
LOG_WARN("failed to destroy hash set", K(tmp_ret), K(ret));
ret = COVER_SUCC(tmp_ret);
}
}
} else {
for (int64_t i = 0; OB_SUCC(ret) && i < right_expr->get_param_count(); ++i) {
if (OB_ISNULL(param_expr = right_expr->get_param_expr(i))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret));
} else if (OB_FAIL(get_equal_sel(table_metas, ctx, *left_expr, *param_expr,
false, tmp_selectivity))) {
LOG_WARN("Failed to get equal sel", K(ret), KPC(left_expr));
} else {
selectivity += tmp_selectivity;
}
}
}
selectivity = revise_between_0_1(selectivity);
if (OB_SUCC(ret) && T_OP_NOT_IN == qual.get_expr_type()) {
selectivity = 1.0 - selectivity;
if (contain_null) {
selectivity = 0.0;
} else if (left_expr->has_flag(CNT_COLUMN) && !right_expr->has_flag(CNT_COLUMN)) {
ObSEArray<ObRawExpr*, 2> cur_vars;
if (OB_FAIL(ObRawExprUtils::extract_column_exprs(left_expr, cur_vars))) {
LOG_WARN("failed to extract column exprs", K(ret));
} else if (1 == cur_vars.count()) { // only one column, consider null_sel
if (OB_ISNULL(cur_vars.at(0))) {
LOG_WARN("expr is null", K(ret));
} else if (OB_FAIL(get_column_basic_sel(table_metas, ctx, *cur_vars.at(0),
&distinct_sel, &null_sel))) {
LOG_WARN("failed to get column basic sel", K(ret));
} else if (distinct_sel > ((1.0 - null_sel) / 2.0)) {
// ndv < 2
// TODO: @yibo 这个refine过程不太理解
selectivity = distinct_sel / 2.0;
} else {
selectivity -= null_sel;
selectivity = std::max(distinct_sel, selectivity); // at least one distinct_sel
}
} else { }//do nothing
}
}
return ret;
}
int ObOptSelectivity::get_is_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity)
{
int ret = OB_SUCCESS;
selectivity = DEFAULT_SEL;
const ParamStore *params = ctx.get_params();
const ObDMLStmt *stmt = ctx.get_stmt();
const ObRawExpr *left_expr = qual.get_param_expr(0);
const ObRawExpr *right_expr = qual.get_param_expr(1);
ObObj result;
bool got_result = false;
if (OB_ISNULL(params) || OB_ISNULL(stmt) || OB_ISNULL(left_expr) || OB_ISNULL(right_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpect null", K(ret), K(params), K(stmt), K(left_expr), K(right_expr));
} else if (OB_UNLIKELY(!ObOptEstUtils::is_calculable_expr(*right_expr, params->count()))) {
// do nothing
} else if (OB_FAIL(ObSQLUtils::calc_const_or_calculable_expr(ctx.get_opt_ctx().get_exec_ctx(),
right_expr,
result,
got_result,
ctx.get_allocator()))) {
LOG_WARN("failed to calculate const or calculable expr", K(ret));
} else if (!got_result) {
// do nothing
} else if (OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(left_expr, left_expr))) {
LOG_WARN("failed to get expr without lossless cast", K(ret));
} else if (left_expr->is_column_ref_expr()) {
if (OB_FAIL(check_column_in_current_level_stmt(stmt, *left_expr))) {
LOG_WARN("Failed to check column whether is in current stmt", K(ret));
} else if (OB_LIKELY(result.is_null())) {
if (OB_FAIL(get_column_basic_sel(table_metas, ctx, *left_expr, NULL, &selectivity))) {
LOG_WARN("Failed to get var distinct sel", K(ret));
}
} else if (result.is_tinyint() &&
!ob_is_string_or_lob_type(left_expr->get_data_type())) {
double distinct_sel = 0.0;
double null_sel = 0.0;
if (OB_FAIL(get_column_basic_sel(table_metas, ctx, *left_expr, &distinct_sel, &null_sel))) {
LOG_WARN("Failed to get var distinct sel", K(ret));
} else {
//distinct_num < 2. That is distinct_num only 1,(As double and statistics not completely accurate,
//use (1 - null_sel)/ 2.0 to check)
if (distinct_sel > (1 - null_sel) / 2.0) {
//Ihe formula to calc sel of 'c1 is true' is (1 - distinct_sel(var = 0) - null_sel).
//If distinct_num is 1, the sel would be 0.0.
//But we don't kown whether distinct value is 0. So gess the selectivity: (1 - null_sel)/2.0
distinct_sel = (1- null_sel) / 2.0;//don't kow the value, just get half.
}
selectivity = (result.is_true()) ? (1 - distinct_sel - null_sel) : distinct_sel;
}
} else { }//default sel
} else {
//TODO func(cnt_column)
}
if (T_OP_IS_NOT == qual.get_expr_type()) {
selectivity = 1.0 - selectivity;
}
return ret;
}
int ObOptSelectivity::get_range_cmp_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity)
{
int ret = OB_SUCCESS;
selectivity = DEFAULT_INEQ_SEL;
const ObRawExpr *left_expr = qual.get_param_expr(0);
const ObRawExpr *right_expr = qual.get_param_expr(1);
if (OB_ISNULL(left_expr) || OB_ISNULL(right_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret), K(left_expr), K(right_expr));
} else if (OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(left_expr, left_expr)) ||
OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(right_expr, right_expr))) {
LOG_WARN("failed to get expr without lossless cast", K(ret));
} else if ((left_expr->is_column_ref_expr() && right_expr->is_const_expr()) ||
(left_expr->is_const_expr() && right_expr->is_column_ref_expr())) {
const ObRawExpr *col_expr = left_expr->is_column_ref_expr() ? left_expr : right_expr;
if (OB_FAIL(get_column_range_sel(table_metas, ctx,
static_cast<const ObColumnRefRawExpr&>(*col_expr),
qual, selectivity))) {
LOG_WARN("Failed to get column range sel", K(qual), K(ret));
}
} else if (T_OP_ROW == left_expr->get_expr_type() && T_OP_ROW == right_expr->get_expr_type()) {
//only deal (col1, xx, xx) CMP (const, xx, xx)
if (left_expr->get_param_count() == 1 && OB_NOT_NULL(left_expr->get_param_expr(0)) &&
T_OP_ROW == left_expr->get_param_expr(0)->get_expr_type()) {
left_expr = left_expr->get_param_expr(0);
}
if (right_expr->get_param_count() == 1 && OB_NOT_NULL(right_expr->get_param_expr(0)) &&
T_OP_ROW == right_expr->get_param_expr(0)->get_expr_type()) {
right_expr = right_expr->get_param_expr(0);
}
if (left_expr->get_param_count() != right_expr->get_param_count()) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("param count should be equal",
K(left_expr->get_param_count()), K(right_expr->get_param_count()));
} else if (left_expr->get_param_count() <= 1) {
// do nothing
} else if (OB_ISNULL(left_expr = left_expr->get_param_expr(0)) ||
OB_ISNULL(right_expr = right_expr->get_param_expr(0))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(left_expr), K(right_expr));
} else if ((left_expr->is_column_ref_expr() && right_expr->is_const_expr()) ||
(left_expr->is_const_expr() && right_expr->is_column_ref_expr())) {
const ObRawExpr *col_expr = (left_expr->is_column_ref_expr()) ? (left_expr) : (right_expr);
if (OB_FAIL(get_column_range_sel(table_metas, ctx,
static_cast<const ObColumnRefRawExpr&>(*col_expr),
qual, selectivity))) {
LOG_WARN("failed to get column range sel", K(ret));
}
} else { /* no dothing */ }
}
return ret;
}
int ObOptSelectivity::get_column_range_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObColumnRefRawExpr &col_expr,
const ObRawExpr &qual,
double &selectivity)
{
int ret = OB_SUCCESS;
ObSEArray<ObRawExpr *, 1> quals;
if (OB_FAIL(quals.push_back(const_cast<ObRawExpr *>(&qual)))) {
LOG_WARN("failed to push back expr", K(ret));
} else if (OB_FAIL(get_column_range_sel(table_metas, ctx, col_expr, quals, selectivity))) {
LOG_WARN("failed to get column range selectivity", K(ret));
}
return ret;
}
int ObOptSelectivity::get_column_range_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObColumnRefRawExpr &col_expr,
const ObIArray<ObRawExpr* > &quals,
double &selectivity)
{
int ret = OB_SUCCESS;
const ObDMLStmt *stmt = ctx.get_stmt();
uint64_t tid = col_expr.get_table_id();
uint64_t cid = col_expr.get_column_id();
ObQueryRange query_range;
ObQueryRangeArray ranges;
ObSEArray<ColumnItem, 1> column_items;
if (OB_ISNULL(stmt)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null stmt", K(ret), K(stmt));
} else if (OB_FAIL(check_column_in_current_level_stmt(stmt, col_expr))) {
LOG_WARN("failed to check if column is in current level stmt", K(col_expr), K(ret));
} else if (OB_FAIL(get_column_query_range(ctx, tid, cid, quals,
column_items, query_range, ranges))) {
LOG_WARN("failed to get column query range", K(ret));
} else {
selectivity = 0.0;
double not_null_sel = 0;
ObOptColumnStatHandle handler;
if (OB_FAIL(get_column_ndv_and_nns(table_metas, ctx, col_expr, NULL, &not_null_sel))) {
LOG_WARN("failed to get column ndv and nns", K(ret));
} else if (OB_FAIL(get_histogram_by_column(table_metas, ctx, tid, cid, handler))) {
LOG_WARN("failed to get histogram by column", K(ret));
} else if (NULL != handler.stat_ &&
handler.stat_->get_last_analyzed() > 0 &&
handler.stat_->get_histogram().is_valid()) {
double hist_scale = 0.0;
if (OB_FAIL(get_column_hist_scale(table_metas, ctx, col_expr, hist_scale))) {
LOG_WARN("failed to get columnn hist sample scale", K(ret));
} else if (OB_FAIL(get_range_sel_by_histogram(handler.stat_->get_histogram(),
ranges,
true,
hist_scale,
selectivity))) {
LOG_WARN("failed to get range sel by histogram", K(ret));
} else {
selectivity *= not_null_sel;
LOG_TRACE("Succeed to get range density ", K(selectivity), K(not_null_sel));
}
} else {
double range_sel = 1.0;
for (int64_t i = 0; OB_SUCC(ret) && i < ranges.count(); ++i) {
if (OB_ISNULL(ranges.at(i))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null range", K(ret), K(i));
} else if (ranges.at(i)->is_whole_range()) {
range_sel = DEFAULT_INEQ_SEL;
} else if (OB_FAIL(get_single_newrange_selectivity(table_metas, ctx, column_items,
*ranges.at(i), range_sel))) {
LOG_WARN("Failed to get single newrange sel", K(ret));
}
selectivity += range_sel;
}
}
if (OB_SUCC(ret)) {
//for range filter, selectivity no more than not_null_sel
if (selectivity > not_null_sel) {
selectivity = not_null_sel;
}
}
LOG_TRACE("Get column range sel", K(selectivity), K(quals));
}
return ret;
}
int ObOptSelectivity::get_single_newrange_selectivity(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObIArray<ColumnItem> &range_columns,
const ObNewRange &range,
double &selectivity)
{
int ret = OB_SUCCESS;
selectivity = 1.0;
if (range.is_whole_range()) {
//Whole range
} else if (range.empty()) {
selectivity = 0;
} else {
const ObRowkey &startkey = range.get_start_key();
const ObRowkey &endkey = range.get_end_key();
if (startkey.get_obj_cnt() == endkey.get_obj_cnt() &&
range_columns.count() == startkey.get_obj_cnt()) {
selectivity = 1.0;
double tmp_selectivity = 1.0;
int64_t column_num = startkey.get_obj_cnt();
//if prefix of range is single value, process next column;
//stop at first range column
bool last_column = false;
const ObColumnRefRawExpr *col_expr = NULL;
for (int64_t i = 0; OB_SUCC(ret) && !last_column && i < column_num; ++i) {
// if (is_like_sel && startobj->is_string_type()
// && startobj->get_string().length() > 0 && '\0' == startobj->get_string()[0]) {
// column_selectivity = DEFAULT_INEQ_SEL;
// range_selectivity *= column_selectivity;
// }
if (OB_ISNULL(col_expr = range_columns.at(i).expr_)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(col_expr));
} else if (OB_FAIL(calc_column_range_selectivity(
table_metas, ctx, *col_expr,
startkey.get_obj_ptr()[i],
endkey.get_obj_ptr()[i],
(col_expr->get_type_class() != ObFloatTC) && (col_expr->get_type_class() != ObDoubleTC),
range.border_flag_,
last_column,
tmp_selectivity))) {
LOG_WARN("failed to calculate column range selectivity", K(ret));
} else {
selectivity *= tmp_selectivity;
}
}
}
}
return ret;
}
int ObOptSelectivity::calc_column_range_selectivity(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &column_expr,
const ObObj &start_obj,
const ObObj &end_obj,
const bool discrete,
const ObBorderFlag border_flag,
bool &last_column,
double &selectivity)
{
int ret = OB_SUCCESS;
last_column = false;
selectivity = DEFAULT_SEL;
double ndv = 0;
double not_null_sel = 0;
ObObj maxobj;
ObObj minobj;
maxobj.set_max_value();
minobj.set_min_value();
if ((start_obj.is_min_value() && end_obj.is_max_value()) ||
(start_obj.is_max_value() && end_obj.is_min_value()) ||
(start_obj.is_max_value() && end_obj.is_max_value()) ||
(start_obj.is_min_value() && end_obj.is_min_value())) {
last_column = true;
selectivity = 1.0;
LOG_TRACE("[RANGE COL SEL] Col is whole range", K(selectivity), K(last_column));
} else if (OB_FAIL(get_column_ndv_and_nns(table_metas, ctx, column_expr, &ndv, &not_null_sel))) {
LOG_WARN("failed to get column ndv and nns", K(ret));
} else if (OB_FAIL(get_column_min_max(table_metas, ctx, column_expr, minobj, maxobj))) {
LOG_WARN("failed to get column min max", K(ret));
} else if (!minobj.is_min_value() && !maxobj.is_max_value()) {
ObObj minscalar;
ObObj maxscalar;
ObObj startscalar;
ObObj endscalar;
const ObObj *new_start_obj = NULL;
const ObObj *new_end_obj = NULL;
ObArenaAllocator tmp_alloc("ObOptSel");
if (OB_FAIL(convert_valid_obj_for_opt_stats(&start_obj, tmp_alloc, new_start_obj)) ||
OB_FAIL(convert_valid_obj_for_opt_stats(&end_obj, tmp_alloc, new_end_obj))) {
LOG_WARN("failed to convert valid obj for opt stats", K(ret), K(start_obj), K(end_obj),
KPC(new_start_obj), KPC(new_end_obj));
} else if (OB_ISNULL(new_start_obj) || OB_ISNULL(new_end_obj)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(new_start_obj), K(new_end_obj));
} else if (new_start_obj->is_null() && new_end_obj->is_null()) {
selectivity = 1 - not_null_sel;
} else if (OB_FAIL(ObOptEstObjToScalar::convert_objs_to_scalars(&minobj, &maxobj,
new_start_obj, new_end_obj,
&minscalar, &maxscalar,
&startscalar, &endscalar))) {
LOG_WARN("failed to convert obj to scalars", K(ret));
} else if (OB_FAIL(do_calc_range_selectivity(minscalar.get_double(),
maxscalar.get_double(),
startscalar,
endscalar,
ndv,
discrete,
border_flag,
last_column,
selectivity))) {
LOG_WARN("failed to do calc range selectivity", K(ret));
} else {
selectivity *= not_null_sel;
}
} else {
bool is_half = start_obj.is_min_value() || end_obj.is_max_value() ||
start_obj.is_max_value() || end_obj.is_min_value();
if (lib::is_oracle_mode()) {
is_half = is_half || (!start_obj.is_null() && (end_obj.is_null()));
} else {
is_half = is_half || (start_obj.is_null() && !(end_obj.is_null()));
}
if (is_half) {
selectivity = OB_DEFAULT_HALF_OPEN_RANGE_SEL;
last_column = true;
LOG_TRACE("[RANGE COL SEL] default half open range sel", K(selectivity), K(last_column));
} else {
//startobj and endobj cannot be min/max in this branch, no need to defend
ObObj startscalar;
ObObj endscalar;
if (OB_FAIL(ObOptEstObjToScalar::convert_objs_to_scalars(NULL, NULL, &start_obj, &end_obj,
NULL, NULL, &startscalar, &endscalar))) {
LOG_WARN("failed to convert objs to scalars", K(ret));
} else {
LOG_TRACE("range column est", K(start_obj), K(end_obj), K(startscalar), K(endscalar));
if (startscalar.is_double() && endscalar.is_double()) {
if (fabs(endscalar.get_double() - startscalar.get_double()) < OB_DOUBLE_EPSINON) {
selectivity = EST_DEF_VAR_EQ_SEL;
LOG_TRACE("[RANGE COL SEL] default single value sel", K(selectivity), K(last_column));
} else {
selectivity = OB_DEFAULT_CLOSED_RANGE_SEL;
last_column = true;
LOG_TRACE("[RANGE COL SEL] default range value sel", K(selectivity), K(last_column));
}
}
}
}
}
return ret;
}
int ObOptSelectivity::do_calc_range_selectivity(const double min,
const double max,
const ObObj &scalar_start,
const ObObj &scalar_end,
const double ndv,
const bool discrete,
const ObBorderFlag &border_flag,
bool &last_column,
double &selectivity)
{
int ret = OB_SUCCESS;
last_column = true;
selectivity = DEFAULT_SEL;
ObBorderFlag flags = border_flag;
if (ndv <= 0) {
selectivity = 0.0;
} else if (!(scalar_start.is_double() || scalar_start.is_min_value() || scalar_start.is_max_value()) ||
!(scalar_end.is_double() || scalar_end.is_min_value() || scalar_end.is_max_value())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected obj type", K(ret), K(scalar_start.get_type()), K(scalar_end.get_type()));
} else {
selectivity = 0.0;
double start = 0.0;
double end = 0.0;
last_column = true;
LOG_TRACE("[DO CALC RANGE] begin calc range expr sel", K(scalar_start), K(scalar_end), K(min), K(max));
if (scalar_start.is_min_value() || scalar_start.is_max_value()) {
start = min;
flags.set_inclusive_start();
} else {
start = scalar_start.get_double();
}
if (scalar_end.is_min_value() || scalar_end.is_max_value()) {
end = max;
flags.set_inclusive_end();
} else {
end = scalar_end.get_double();
}
if (fabs(start - end) < OB_DOUBLE_EPSINON) {
selectivity = 1.0 / ndv; //Single value
last_column = false;
LOG_TRACE("[DO CALC RANGE] single value");
} else {
if (start < min) {
start = min;
flags.set_inclusive_start();
}
if (end > max) {
end = max;
flags.set_inclusive_end();
}
if (start > end) { // (start is min_value and end < min) or (end is max and start > max)
selectivity = 0.0;
} else if (fabs(max - min) < OB_DOUBLE_EPSINON) {
selectivity = fabs(end - start) < OB_DOUBLE_EPSINON ? 1.0 : 0.0;
} else {
selectivity = (end - start) / (max - min);
selectivity = revise_range_sel(selectivity, ndv, discrete,
flags.inclusive_start(),
flags.inclusive_end());
}
}
}
return ret;
}
double ObOptSelectivity::revise_range_sel(double selectivity,
double distinct,
bool discrete,
bool include_start,
bool include_end)
{
if (discrete) {
if (!include_start && !include_end) {
selectivity -= 1.0 / distinct;
} else if (include_start && include_end) {
selectivity += 1.0 / distinct;
} else { }//do nothing
} else if (include_start && include_end) {
selectivity += 2.0 / distinct;
} else if (include_start || include_end) {
selectivity += 1.0 / distinct;
} else if (selectivity == 1.0) {
//if not include both start and end, and the selectivity is 1.0, should minus 1/ndv
//eg: min-max: [1, 4], start-end is (1,4] or [1, 4);
selectivity -= 1.0 / distinct;
}
return revise_between_0_1(selectivity);
}
int ObOptSelectivity::get_like_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity)
{
int ret = OB_SUCCESS;
selectivity = DEFAULT_INEQ_SEL;
const ObRawExpr *variable = NULL;
const ObRawExpr *pattern = NULL;
const ObRawExpr *escape = NULL;
const ParamStore *params = ctx.get_params();
if (3 != qual.get_param_count()) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("like expr should have 3 param", K(ret), K(qual));
} else if (OB_ISNULL(params) ||
OB_ISNULL(variable = qual.get_param_expr(0)) ||
OB_ISNULL(pattern = qual.get_param_expr(1)) ||
OB_ISNULL(escape = qual.get_param_expr(2))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null params", K(ret), K(params), K(variable), K(pattern), K(escape));
} else if (OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(variable, variable))) {
LOG_WARN("failed to get expr without lossless cast", K(ret));
} else if (variable->is_column_ref_expr() &&
ObOptEstUtils::is_calculable_expr(*pattern, params->count()) &&
ObOptEstUtils::is_calculable_expr(*escape, params->count())) {
bool is_start_with = false;
if (is_lob_storage(variable->get_data_type())) {
// no statistics for lob type, use default selectivity
selectivity = DEFAULT_CLOB_LIKE_SEL;
} else if (OB_FAIL(ObOptEstUtils::if_expr_start_with_patten_sign(params, pattern, escape,
ctx.get_opt_ctx().get_exec_ctx(),
ctx.get_allocator(),
is_start_with))) {
LOG_WARN("failed to check if expr start with percent sign", K(ret));
} else if (is_start_with) {
// do nothing
} else if (OB_FAIL(get_column_range_sel(table_metas, ctx,
static_cast<const ObColumnRefRawExpr&>(*variable),
qual, selectivity))) {
LOG_WARN("Failed to get column range selectivity", K(ret));
}
}
return ret;
}
int ObOptSelectivity::get_btw_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity)
{
int ret = OB_SUCCESS;
selectivity = DEFAULT_SEL;
const ObRawExpr *cmp_expr = NULL;
const ObRawExpr *l_expr = NULL;
const ObRawExpr *r_expr = NULL;
const ObRawExpr *col_expr = NULL;
const ParamStore *params = ctx.get_params();
if (3 != qual.get_param_count()) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("between expr should have 3 param", K(ret), K(qual));
} else if (OB_ISNULL(params) ||
OB_ISNULL(cmp_expr = qual.get_param_expr(0)) ||
OB_ISNULL(l_expr = qual.get_param_expr(1)) ||
OB_ISNULL(r_expr = qual.get_param_expr(2))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null params", K(ret), K(params), K(cmp_expr), K(l_expr), K(r_expr));
} else if (OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(cmp_expr, cmp_expr))) {
LOG_WARN("failed to get expr without lossless cast", K(ret));
} else if (cmp_expr->is_column_ref_expr() &&
ObOptEstUtils::is_calculable_expr(*l_expr, params->count()) &&
ObOptEstUtils::is_calculable_expr(*r_expr, params->count())) {
col_expr = cmp_expr;
} else if (ObOptEstUtils::is_calculable_expr(*cmp_expr, params->count()) &&
l_expr->is_column_ref_expr() &&
ObOptEstUtils::is_calculable_expr(*r_expr, params->count())) {
col_expr = l_expr;
} else if (ObOptEstUtils::is_calculable_expr(*cmp_expr, params->count()) &&
ObOptEstUtils::is_calculable_expr(*l_expr, params->count()) &&
r_expr->is_column_ref_expr()) {
col_expr = r_expr;
}
if (NULL != col_expr) {
if (OB_FAIL(get_column_range_sel(table_metas, ctx,
static_cast<const ObColumnRefRawExpr&>(*col_expr),
qual, selectivity))) {
LOG_WARN("failed to get column range sel", K(ret));
}
}
return ret;
}
int ObOptSelectivity::get_not_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity,
ObIArray<ObExprSelPair> &all_predicate_sel)
{
int ret = OB_SUCCESS;
selectivity = DEFAULT_SEL;
const ObRawExpr *child_expr = qual.get_param_expr(0);
double tmp_selectivity = 1.0;
ObSEArray<ObRawExpr*, 3> cur_vars;
if (OB_ISNULL(child_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret));
} else if (OB_FAIL(calculate_qual_selectivity(table_metas, ctx, *child_expr,
tmp_selectivity, all_predicate_sel))) {
LOG_WARN("failed to calculate one qual selectivity", K(child_expr), K(ret));
} else if (OB_FAIL(ObRawExprUtils::extract_column_exprs(child_expr, cur_vars))) {
LOG_WARN("failed to extract column exprs", K(ret));
} else if (1 == cur_vars.count() &&
T_OP_IS != child_expr->get_expr_type() &&
T_OP_IS_NOT != child_expr->get_expr_type() &&
T_OP_NSEQ != child_expr->get_expr_type()) { // for only one column, consider null_sel
double null_sel = 1.0;
if (OB_ISNULL(cur_vars.at(0))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret));
} else if (OB_FAIL(get_column_basic_sel(table_metas, ctx, *cur_vars.at(0), NULL, &null_sel))) {
LOG_WARN("failed to get column basic sel", K(ret));
} else {
selectivity = 1.0 - null_sel - tmp_selectivity;
}
} else {
// for other condition, it's is too hard to consider null_sel, so ignore it.
// t_op_is, t_op_nseq , they are null safe exprs, don't consider null_sel.
selectivity = 1.0 - tmp_selectivity;
}
return ret;
}
int ObOptSelectivity::get_ne_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity)
{
int ret = OB_SUCCESS;
const ObRawExpr *left_expr = qual.get_param_expr(0);
const ObRawExpr *right_expr = qual.get_param_expr(1);
if (OB_ISNULL(left_expr) || OB_ISNULL(right_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret), K(qual), K(left_expr), K(right_expr));
} else if (OB_FAIL(get_ne_sel(table_metas, ctx, *left_expr, *right_expr, selectivity))) {
LOG_WARN("failed to get equal sel", K(ret));
}
return ret;
}
int ObOptSelectivity::get_ne_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &l_expr,
const ObRawExpr &r_expr,
double &selectivity)
{
int ret = OB_SUCCESS;
selectivity = DEFAULT_SEL;
if (T_OP_ROW == l_expr.get_expr_type() && T_OP_ROW == r_expr.get_expr_type()) {
// (var1, var2) != (var3, var4) => var1 != var3 or var2 != var4
selectivity = 0;
double tmp_selectivity = 1.0;
const ObRawExpr *l_param = NULL;
const ObRawExpr *r_param = NULL;
const ObRawExpr *l_row = &l_expr;
const ObRawExpr *r_row = &r_expr;
if (l_expr.get_param_count() == 1 && OB_NOT_NULL(l_expr.get_param_expr(0)) &&
T_OP_ROW == l_expr.get_param_expr(0)->get_expr_type()) {
l_row = l_expr.get_param_expr(0);
}
if (r_expr.get_param_count() == 1 && OB_NOT_NULL(r_expr.get_param_expr(0)) &&
T_OP_ROW == r_expr.get_param_expr(0)->get_expr_type()) {
r_row = r_expr.get_param_expr(0);
}
if (OB_UNLIKELY(l_row->get_param_count() != r_row->get_param_count())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected expr", KPC(l_row), KPC(r_row), K(ret));
} else {
int64_t num = l_row->get_param_count();
for (int64_t i = 0; OB_SUCC(ret) && i < num; ++i) {
if (OB_ISNULL(l_param = l_row->get_param_expr(i)) ||
OB_ISNULL(r_param = r_row->get_param_expr(i))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret), K(l_row), K(r_row), K(i));
} else if (OB_FAIL(SMART_CALL(get_ne_sel(table_metas, ctx, *l_param,
*r_param, tmp_selectivity)))) {
LOG_WARN("failed to get equal selectivity", K(ret));
} else {
selectivity += tmp_selectivity - selectivity * tmp_selectivity;
}
}
}
} else if (l_expr.has_flag(CNT_COLUMN) && r_expr.has_flag(CNT_COLUMN)) {
if (OB_FAIL(get_cntcol_op_cntcol_sel(table_metas, ctx, l_expr, r_expr, T_OP_NE, selectivity))) {
LOG_WARN("failed to get cntcol op cntcol sel", K(ret));
}
} else if ((l_expr.has_flag(CNT_COLUMN) && !r_expr.has_flag(CNT_COLUMN)) ||
(!l_expr.has_flag(CNT_COLUMN) && r_expr.has_flag(CNT_COLUMN))) {
const ObRawExpr *cnt_col_expr = l_expr.has_flag(CNT_COLUMN) ? &l_expr : &r_expr;
const ObRawExpr *const_expr = l_expr.has_flag(CNT_COLUMN) ? &r_expr : &l_expr;
ObSEArray<const ObColumnRefRawExpr *, 2> column_exprs;
bool only_monotonic_op = true;
bool null_const = false;
double ndv = 1.0;
double nns = 0;
bool can_use_hist = false;
ObObj expr_value;
ObOptColumnStatHandle handler;
if (OB_FAIL(ObOptimizerUtil::get_expr_without_lossless_cast(cnt_col_expr, cnt_col_expr))) {
LOG_WARN("failed to check is lossless column cast", K(ret));
} else if (cnt_col_expr->is_column_ref_expr()) {
// column != const
const ObColumnRefRawExpr *col = static_cast<const ObColumnRefRawExpr*>(cnt_col_expr);
if (OB_FAIL(get_histogram_by_column(table_metas, ctx, col->get_table_id(),
col->get_column_id(), handler))) {
LOG_WARN("failed to get histogram by column", K(ret));
} else if (handler.stat_ == NULL || !handler.stat_->get_histogram().is_valid()) {
// do nothing
} else if (OB_FAIL(get_compare_value(ctx, col, const_expr, expr_value, can_use_hist))) {
// cast may failed due to invalid type or value out of range.
// Then use ndv instead of histogram
can_use_hist = false;
ret = OB_SUCCESS;
}
}
if (OB_SUCC(ret)) {
if (can_use_hist) {
double hist_scale = 0;
if (OB_FAIL(get_column_hist_scale(table_metas, ctx, *cnt_col_expr, hist_scale))) {
LOG_WARN("failed to get columnn hist sample scale", K(ret));
} else if (OB_FAIL(get_equal_pred_sel(handler.stat_->get_histogram(), expr_value, hist_scale, selectivity))) {
LOG_WARN("Failed to get equal density", K(ret));
} else if (OB_FAIL(get_column_ndv_and_nns(table_metas, ctx, *cnt_col_expr, NULL, &nns))) {
LOG_WARN("failed to get column ndv and nns", K(ret));
} else {
selectivity = (1.0 - selectivity) * nns;
}
} else if (OB_FAIL(ObOptEstUtils::extract_column_exprs_with_op_check(cnt_col_expr,
column_exprs,
only_monotonic_op))) {
LOG_WARN("failed to extract column exprs with op check", K(ret));
} else if (!only_monotonic_op || column_exprs.count() > 1) {
selectivity = DEFAULT_SEL; //cnt_col_expr contain not monotonic op OR has more than 1 var
} else if (OB_UNLIKELY(1 != column_exprs.count()) || OB_ISNULL(column_exprs.at(0))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected contain column expr", K(ret), K(*cnt_col_expr));
} else if (OB_FAIL(ObOptEstUtils::if_expr_value_null(ctx.get_params(),
*const_expr,
ctx.get_opt_ctx().get_exec_ctx(),
ctx.get_allocator(),
null_const))) {
LOG_WARN("Failed to check whether expr null value", K(ret));
} else if (null_const) {
selectivity = 0.0;
} else if (OB_FAIL(get_column_ndv_and_nns(table_metas, ctx, *column_exprs.at(0), &ndv, &nns))) {
LOG_WARN("failed to get column ndv and nns", K(ret));
} else if (ndv < 2.0) {
//The reason doing this is similar as get_is_sel function.
//If distinct_num is 1, As formula, selectivity of 'c1 != 1' would be 0.0.
//But we don't know the distinct value, so just get the half selectivity.
selectivity = nns / ndv / 2.0;
} else {
selectivity = nns * (1.0 - 1 / ndv);
}
}
} else { }//do nothing
return ret;
}
int ObOptSelectivity::get_agg_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &qual,
double &selectivity)
{
int ret = OB_SUCCESS;
const double origin_rows = ctx.get_row_count_1(); // rows before group by
const double grouped_rows = ctx.get_row_count_2();// rows after group by
bool is_valid = false;
const ObRawExpr *aggr_expr = NULL;
const ObRawExpr *const_expr1 = NULL;
const ObRawExpr *const_expr2 = NULL;
selectivity = DEFAULT_AGG_RANGE;
ObItemType type = qual.get_expr_type();
// for aggregate function in having clause, only support
// = <=> != > >= < <= [not] btw [not] in
if (-1.0 == origin_rows || -1.0 == grouped_rows) {
// 不是在group by层计算的having filter，使用默认选择率
// e.g. select * from t7 group by c1 having count(*) > (select c1 from t8 limit 1);
// 该sql中having filter需要在subplan filter中计算
} else if ((type >= T_OP_EQ && type <= T_OP_NE) ||
T_OP_IN == type || T_OP_NOT_IN == type ||
T_OP_BTW == type || T_OP_NOT_BTW == type) {
if (OB_FAIL(is_valid_agg_qual(qual, is_valid, aggr_expr, const_expr1, const_expr2))) {
LOG_WARN("failed to check is valid agg qual", K(ret));
} else if (!is_valid) {
/* use default selectivity */
} else if (OB_ISNULL(aggr_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else if (T_FUN_MAX == aggr_expr->get_expr_type() ||
T_FUN_MIN == aggr_expr->get_expr_type() ||
T_FUN_COUNT == aggr_expr->get_expr_type()) {
if (T_OP_EQ == type || T_OP_NSEQ == type) {
selectivity = DEFAULT_AGG_EQ;
} else if (T_OP_NE == type || IS_RANGE_CMP_OP(type)) {
selectivity = DEFAULT_AGG_RANGE;
} else if (T_OP_BTW == type) {
// agg(col) btw const1 and const2 <=> agg(col) > const1 AND agg(col) < const2
selectivity = DEFAULT_AGG_RANGE * DEFAULT_AGG_RANGE;
} else if (T_OP_NOT_BTW == type) {
// agg(col) not btw const1 and const2 <=> agg(col) < const1 OR agg(col) > const2
// 计算方式参考OR
selectivity = DEFAULT_AGG_RANGE + DEFAULT_AGG_RANGE;
} else if (T_OP_IN == type) {
/**
* oracle 对 max/min/count(col) in (const1, const2, const3, ...)的选择率估计
* 当const的数量小于等于5时，每增加一个const值，选择率增加 DEFAULT_AGG_EQ(0.01)
* 当const的数量大于5时，每增加一个const值，选择率增加
* DEFAULT_AGG_EQ - 0.001 * (const_num - 5)
* # 这里的选择率增加量采用线性下降其实并不是很精确，oracle的选择率增加量可能采用了了指数下降，
* 在测试过程中测试了1-30列递增的情况，线性下降和指数下降区别不大。
*/
int64_t N;
if(OB_ISNULL(const_expr1)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null");
} else if (FALSE_IT(N = const_expr1->get_param_count())) {
} else if (N < 6) {
selectivity = DEFAULT_AGG_EQ * N;
} else {
N = std::min(N, 15L);
selectivity = DEFAULT_AGG_EQ * 5 + (DEFAULT_AGG_EQ - 0.0005 * (N - 4)) * (N - 5);
}
} else if (T_OP_NOT_IN == type) {
// agg(col) not in (const1, const2, ...) <=> agg(col) != const1 and agg(col) != const2 and ...
if(OB_ISNULL(const_expr1)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null");
} else {
selectivity = std::pow(DEFAULT_AGG_RANGE, const_expr1->get_param_count());
}
} else { /* use default selectivity */ }
} else if (T_FUN_SUM == aggr_expr->get_expr_type() || T_FUN_AVG == aggr_expr->get_expr_type()) {
LOG_TRACE("show group by origen rows and grouped rows", K(origin_rows), K(grouped_rows));
double rows_per_group = grouped_rows == 0.0 ? origin_rows : origin_rows / grouped_rows;
if (OB_FAIL(get_agg_sel_with_minmax(table_metas, ctx, *aggr_expr, const_expr1,
const_expr2, type, selectivity, rows_per_group))) {
LOG_WARN("failed to get agg sel with minmax", K(ret));
}
} else { /* not max/min/count/sum/avg, use default selectivity */ }
} else { /* use default selectivity */ }
return ret;
}
int ObOptSelectivity::get_agg_sel_with_minmax(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &aggr_expr,
const ObRawExpr *const_expr1,
const ObRawExpr *const_expr2,
const ObItemType type,
double &selectivity,
const double rows_per_group)
{
int ret = OB_SUCCESS;
selectivity = DEFAULT_AGG_RANGE;
const ParamStore *params = ctx.get_params();
const ObDMLStmt *stmt = ctx.get_stmt();
ObExecContext *exec_ctx = ctx.get_opt_ctx().get_exec_ctx();
ObIAllocator &alloc = ctx.get_allocator();
ObObj result1;
ObObj result2;
bool got_result;
double distinct_sel = 1.0;
ObObj maxobj;
ObObj minobj;
maxobj.set_max_value();
minobj.set_min_value();
if (OB_ISNULL(aggr_expr.get_param_expr(0)) || OB_ISNULL(params) ||
OB_ISNULL(stmt) || OB_ISNULL(const_expr1)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(aggr_expr.get_param_expr(0)),
K(params), K(stmt), K(const_expr1));
} else if (!aggr_expr.get_param_expr(0)->is_column_ref_expr()) {
// 只处理sum(column)的形式，sum(column + 1)/sum(column1 + column2)都是用默认选择率
} else if (OB_FAIL(get_column_basic_sel(table_metas, ctx, *aggr_expr.get_param_expr(0),
&distinct_sel, NULL))) {
LOG_WARN("failed to get column basic sel", K(ret));
} else if (OB_FAIL(get_column_min_max(table_metas, ctx, *aggr_expr.get_param_expr(0),
minobj, maxobj))) {
LOG_WARN("failed to get column min max", K(ret));
} else if (minobj.is_min_value() || maxobj.is_max_value()) {
// do nothing
} else if (T_OP_IN == type || T_OP_NOT_IN == type) {
if (OB_UNLIKELY(T_OP_ROW != const_expr1->get_expr_type())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("expr should be row", K(ret), K(*const_expr1));
} else {
// 如果row超过5列，则计算5列上的选择率，再按比例放大
int64_t N = const_expr1->get_param_count() > 5 ? 5 :const_expr1->get_param_count();
selectivity = T_OP_IN == type ? 0.0 : 1.0;
for (int64_t i = 0; OB_SUCC(ret) && i < N; ++i) {
double tmp_sel = T_OP_IN == type ? DEFAULT_AGG_EQ : DEFAULT_AGG_RANGE;
const ObRawExpr *sub_expr = NULL;
ObObj tmp_result;
if (OB_ISNULL(sub_expr = const_expr1->get_param_expr(i))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else if (!ObOptEstUtils::is_calculable_expr(*sub_expr, params->count())) {
} else if (OB_FAIL(ObSQLUtils::calc_const_or_calculable_expr(exec_ctx,
sub_expr,
tmp_result,
got_result,
alloc))) {
LOG_WARN("failed to calc const or calculable expr", K(ret));
} else if (!got_result) {
// do nothing
} else {
tmp_sel = get_agg_eq_sel(maxobj, minobj, tmp_result, distinct_sel, rows_per_group,
T_OP_IN == type, T_FUN_SUM == aggr_expr.get_expr_type());
}
if (T_OP_IN == type) {
selectivity += tmp_sel;
} else {
selectivity *= tmp_sel;
}
}
if (OB_SUCC(ret)) {
selectivity *= static_cast<double>(const_expr1->get_param_count())
/ static_cast<double>(N);
}
}
} else if (!ObOptEstUtils::is_calculable_expr(*const_expr1, params->count())) {
} else if (OB_FAIL(ObSQLUtils::calc_const_or_calculable_expr(exec_ctx,
const_expr1,
result1,
got_result,
alloc))) {
LOG_WARN("failed to calc const or calculable expr", K(ret));
} else if (!got_result) {
// do nothing
} else if (T_OP_EQ == type || T_OP_NSEQ == type) {
selectivity = get_agg_eq_sel(maxobj, minobj, result1, distinct_sel, rows_per_group,
true, T_FUN_SUM == aggr_expr.get_expr_type());
} else if (T_OP_NE == type) {
selectivity = get_agg_eq_sel(maxobj, minobj, result1, distinct_sel, rows_per_group,
false, T_FUN_SUM == aggr_expr.get_expr_type());
} else if (IS_RANGE_CMP_OP(type)) {
selectivity = get_agg_range_sel(maxobj, minobj, result1, rows_per_group,
type, T_FUN_SUM == aggr_expr.get_expr_type());
} else if (T_OP_BTW == type || T_OP_NOT_BTW == type) {
if (OB_ISNULL(const_expr2)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else if (!ObOptEstUtils::is_calculable_expr(*const_expr2, params->count())) {
} else if (OB_FAIL(ObSQLUtils::calc_const_or_calculable_expr(exec_ctx,
const_expr2,
result2,
got_result,
alloc))) {
LOG_WARN("Failed to calc const or calculable expr", K(ret));
} else if (!got_result) {
// do nothing
} else {
selectivity = get_agg_btw_sel(maxobj, minobj, result1, result2, rows_per_group,
type, T_FUN_SUM == aggr_expr.get_expr_type());
}
} else { /* do nothing */ }
return ret;
}
// 计算sum/avg(col) =/<=>/!= const的选择率
double ObOptSelectivity::get_agg_eq_sel(const ObObj &maxobj,
const ObObj &minobj,
const ObObj &constobj,
const double distinct_sel,
const double rows_per_group,
const bool is_eq,
const bool is_sum)
{
int ret = OB_SUCCESS;
double sel_ret = DEFAULT_AGG_EQ;
if (constobj.is_null()) {
// sum/avg(col)的结果中不会存在null，即使是null safe equal选择率依然为0
sel_ret = 0.0;
} else if (minobj.is_integer_type() ||
(minobj.is_number() && minobj.get_meta().get_obj_meta().get_scale() == 0) ||
(minobj.is_unumber() && minobj.get_meta().get_obj_meta().get_scale() == 0)) {
double const_val;
double min_val;
double max_val;
// 如果转化的时候出错，就使用默认的选择率
if (OB_FAIL(ObOptEstObjToScalar::convert_obj_to_double(&constobj, const_val)) ||
OB_FAIL(ObOptEstObjToScalar::convert_obj_to_double(&minobj, min_val)) ||
OB_FAIL(ObOptEstObjToScalar::convert_obj_to_double(&maxobj, max_val))) {
LOG_WARN("failed to convert obj to double", K(ret));
} else {
LOG_TRACE("get values for agg eq sel", K(max_val), K(min_val), K(const_val));
if (is_sum) {
min_val *= rows_per_group;
max_val *= rows_per_group;
}
int64_t length = max_val - min_val + 1;
if (is_eq) {
sel_ret = 1.0 / length;
if (const_val < min_val) {
sel_ret -= sel_ret * (min_val - const_val) / length;
} else if (const_val > max_val) {
sel_ret -= sel_ret * (const_val - max_val) / length;
} else {}
} else {
sel_ret = 1.0 - 1.0 / length;
}
}
} else {
// 对于非整数的类型，认为sum/avg(col)后 ndv 不会发生显著变化，直接使用该列原有的ndv计算
sel_ret = is_eq ? distinct_sel : 1.0 - distinct_sel;
}
sel_ret = revise_between_0_1(sel_ret);
return sel_ret;
}
// 计算sum/avg(col) >/>=/</<= const的选择率
double ObOptSelectivity::get_agg_range_sel(const ObObj &maxobj,
const ObObj &minobj,
const ObObj &constobj,
const double rows_per_group,
const ObItemType type,
const bool is_sum)
{
int ret = OB_SUCCESS;
double sel_ret = DEFAULT_AGG_RANGE;
if (constobj.is_null()) {
// sum/avg(col)的结果中不会存在null，因此选择率为0
sel_ret = 0.0;
} else {
double min_val;
double max_val;
double const_val;
// 如果转化的时候出错，就使用默认的选择率
if (OB_FAIL(ObOptEstObjToScalar::convert_obj_to_double(&minobj, min_val))) {
LOG_WARN("failed to convert obj to double", K(ret));
} else if (OB_FAIL(ObOptEstObjToScalar::convert_obj_to_double(&maxobj, max_val))) {
LOG_WARN("failed to convert obj to double", K(ret));
} else if (OB_FAIL(ObOptEstObjToScalar::convert_obj_to_double(&constobj, const_val))) {
LOG_WARN("failed to convert obj to double", K(ret));
} else {
LOG_TRACE("get values for agg range sel", K(max_val), K(min_val), K(const_val));
if (is_sum) {
min_val *= rows_per_group;
max_val *= rows_per_group;
}
double length = max_val - min_val + 1.0;
if (T_OP_GE == type || T_OP_GT == type) {
if (T_OP_GT == type) {
// c1 > 1 <=> c1 >= 2, 对非int类型的列并不精确
const_val += 1.0;
}
if (const_val <= min_val) {
sel_ret = 1.0;
} else if (const_val <= max_val) {
sel_ret = (max_val - const_val + 1.0) / length;
} else {
sel_ret = 1.0 / length;
sel_ret -= sel_ret * (const_val - max_val) / length;
}
} else if (T_OP_LE == type || T_OP_LT == type) {
if (T_OP_LT == type) {
// c1 < 1 <=> c1 <= 0, 对非int类型的列并不精确
const_val -= 1.0;
}
if (const_val >= max_val) {
sel_ret = 1.0;
} else if (const_val >= min_val) {
sel_ret = (const_val - min_val + 1.0) / length;
} else {
sel_ret = 1.0 / length;
sel_ret -= sel_ret * (min_val - const_val) / length;
}
} else { /* do nothing */ }
}
}
sel_ret = revise_between_0_1(sel_ret);
return sel_ret;
}
// 计算sum/avg(col) [not] between const1 and const2的选择率
double ObOptSelectivity::get_agg_btw_sel(const ObObj &maxobj,
const ObObj &minobj,
const ObObj &constobj1,
const ObObj &constobj2,
const double rows_per_group,
const ObItemType type,
const bool is_sum)
{
int ret = OB_SUCCESS;
double sel_ret = DEFAULT_AGG_RANGE;
if (constobj1.is_null() || constobj2.is_null()) {
sel_ret= 0.0;
} else {
double min_val;
double max_val;
double const_val1;
double const_val2;
// 如果转化的时候出错，就使用默认的选择率
if (OB_FAIL(ObOptEstObjToScalar::convert_obj_to_double(&minobj, min_val))) {
LOG_WARN("failed to convert obj to double", K(ret));
} else if (OB_FAIL(ObOptEstObjToScalar::convert_obj_to_double(&maxobj, max_val))) {
LOG_WARN("failed to convert obj to double", K(ret));
} else if (OB_FAIL(ObOptEstObjToScalar::convert_obj_to_double(&constobj1, const_val1))) {
LOG_WARN("failed to convert obj to double", K(ret));
} else if (OB_FAIL(ObOptEstObjToScalar::convert_obj_to_double(&constobj2, const_val2))) {
LOG_WARN("failed to convert obj to double", K(ret));
} else {
LOG_TRACE("get values for agg between sel", K(max_val), K(min_val), K(const_val1), K(const_val2));
if (is_sum) {
min_val *= rows_per_group;
max_val *= rows_per_group;
}
double length = max_val - min_val + 1.0;
if (T_OP_BTW == type) {
if (const_val1 > const_val2) {
sel_ret = 0.0;
} else {
double tmp_min = std::max(const_val1, min_val);
double tmp_max = std::min(const_val2, max_val);
sel_ret = (tmp_max - tmp_min + 1.0) / length;
}
} else if (T_OP_NOT_BTW == type){
if (const_val1 > const_val2) {
sel_ret = 1.0;
} else {
double tmp_min = std::max(const_val1, min_val);
double tmp_max = std::min(const_val2, max_val);
sel_ret = 1 - (tmp_max - tmp_min + 1.0) / length;
}
} else { /* do nothing */ }
}
}
sel_ret = revise_between_0_1(sel_ret);
return sel_ret;
}
int ObOptSelectivity::is_valid_agg_qual(const ObRawExpr &qual,
bool &is_valid,
const ObRawExpr *&aggr_expr,
const ObRawExpr *&const_expr1,
const ObRawExpr *&const_expr2)
{
int ret = OB_SUCCESS;
is_valid = false;
const ObRawExpr *expr0 = NULL;
const ObRawExpr *expr1 = NULL;
const ObRawExpr *expr2 = NULL;
if (T_OP_BTW == qual.get_expr_type() || T_OP_NOT_BTW == qual.get_expr_type()) {
if (OB_ISNULL(expr0 = qual.get_param_expr(0)) ||
OB_ISNULL(expr1 = qual.get_param_expr(1)) ||
OB_ISNULL(expr2 = qual.get_param_expr(2))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else if (expr0->has_flag(IS_AGG) &&
expr1->is_const_expr() &&
expr2->is_const_expr()) {
is_valid = true;
aggr_expr = expr0;
const_expr1 = expr1;
const_expr2 = expr2;
} else { /* do nothing */ }
} else {
if (OB_ISNULL(expr0 = qual.get_param_expr(0)) || OB_ISNULL(expr1 = qual.get_param_expr(1))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else if (T_OP_IN == qual.get_expr_type() || T_OP_NOT_IN == qual.get_expr_type()) {
if (!qual.has_flag(CNT_SUB_QUERY) &&
expr0->has_flag(IS_AGG) &&
T_OP_ROW == expr1->get_expr_type()) {
is_valid = true;
aggr_expr = expr0;
const_expr1 = expr1;
} else { /* do nothing */ }
} else if (expr0->has_flag(IS_AGG) &&
expr1->is_const_expr()) {
is_valid = true;
aggr_expr = expr0;
const_expr1 = expr1;
} else if (expr0->is_const_expr() &&
expr1->has_flag(IS_AGG)) {
is_valid = true;
aggr_expr = expr1;
const_expr1 = expr0;
} else { /* do nothing */ }
}
return ret;
}
int ObOptSelectivity::check_column_in_current_level_stmt(const ObDMLStmt *stmt,
const ObRawExpr &expr)
{
int ret = OB_SUCCESS;
bool is_in = false;
if (OB_FAIL(column_in_current_level_stmt(stmt, expr, is_in))) {
LOG_WARN("failed to check if column is in current level stmt", K(expr), K(ret));
} else if (!is_in) {
// TODO:@yibo should not reach here
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected expr", K(ret), K(expr), K(stmt->get_table_items()), KPC(stmt));
}
return ret;
}
int ObOptSelectivity::column_in_current_level_stmt(const ObDMLStmt *stmt,
const ObRawExpr &expr,
bool &is_in)
{
int ret = OB_SUCCESS;
is_in = false;
if (OB_ISNULL(stmt)) {
ret = OB_INVALID_ARGUMENT;
LOG_WARN("Stmt is NULL", K(stmt), K(ret));
} else if (stmt->is_select_stmt() && static_cast<const ObSelectStmt*>(stmt)->is_set_stmt()) {
// TODO:@yibo 这里看起来没什么意义，后面检查一下
const ObSelectStmt *select_stmt = static_cast<const ObSelectStmt*>(stmt);
const ObIArray<ObSelectStmt*> &child_query = select_stmt->get_set_query();
for (int64_t i = 0; OB_SUCC(ret) && !is_in && i < child_query.count(); ++i) {
ret = SMART_CALL(column_in_current_level_stmt(child_query.at(i), expr, is_in));
}
} else if (expr.is_column_ref_expr()) {
// TODO:@yibo 正常走到这里的时候，上层stmt的column都被抽成？了
const ObColumnRefRawExpr &b_expr = static_cast<const ObColumnRefRawExpr&>(expr);
const TableItem *table_item = stmt->get_table_item_by_id(b_expr.get_table_id());
if (NULL != table_item) {
is_in = true;
}
}
return ret;
}
int ObOptSelectivity::get_column_basic_sel(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &expr,
double *distinct_sel_ptr,
double *null_sel_ptr)
{
int ret = OB_SUCCESS;
double row_count;
double ndv;
double num_null;
if (OB_FAIL(get_column_basic_info(table_metas, ctx, expr, &ndv, &num_null, NULL, &row_count))) {
LOG_WARN("failed to get column basic info", K(ret));
} else {
double null_sel = row_count <= OB_DOUBLE_EPSINON ? 0.0 : revise_between_0_1(num_null / row_count);
double distinct_sel = ndv <= OB_DOUBLE_EPSINON ? 0.0 : revise_between_0_1((1 - null_sel) / ndv);
assign_value(distinct_sel, distinct_sel_ptr);
assign_value(null_sel, null_sel_ptr);
LOG_TRACE("column basic sel info", K(distinct_sel), K(null_sel));
}
return ret;
}
int ObOptSelectivity::get_column_ndv_and_nns(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &expr,
double *ndv_ptr,
double *not_null_sel_ptr)
{
int ret = OB_SUCCESS;
double row_count;
double ndv;
double num_null;
if (OB_FAIL(get_column_basic_info(table_metas, ctx, expr, &ndv, &num_null, NULL, &row_count))) {
LOG_WARN("failed to get column basic info", K(ret));
} else {
double not_null_sel = row_count <= OB_DOUBLE_EPSINON ? 1.0 : 1 - revise_between_0_1(num_null / row_count);
assign_value(ndv, ndv_ptr);
assign_value(not_null_sel, not_null_sel_ptr);
LOG_TRACE("column ndv and not null sel", K(ndv), K(not_null_sel));
}
return ret;
}
int ObOptSelectivity::get_column_min_max(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &expr,
ObObj &min_obj,
ObObj &max_obj)
{
int ret = OB_SUCCESS;
if (OB_UNLIKELY(!expr.is_column_ref_expr())) {
ret = OB_INVALID_ARGUMENT;
LOG_WARN("get invalid expr", K(ret), K(expr));
} else {
const ObColumnRefRawExpr &column_expr = static_cast<const ObColumnRefRawExpr&>(expr);
uint64_t table_id = column_expr.get_table_id();
uint64_t column_id = column_expr.get_column_id();
const OptTableMeta *table_meta = table_metas.get_table_meta_by_table_id(table_id);
OptColumnMeta *column_meta = const_cast<OptColumnMeta *>(
table_metas.get_column_meta_by_table_id(table_id, column_id));
if (OB_NOT_NULL(table_meta) && OB_NOT_NULL(column_meta)) {
if (column_meta->get_min_max_inited()) {
min_obj = column_meta->get_min_value();
max_obj = column_meta->get_max_value();
} else if (OB_ISNULL(ctx.get_opt_stat_manager()) || OB_ISNULL(ctx.get_session_info())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(ctx.get_opt_stat_manager()),
K(ctx.get_session_info()));
} else if (table_meta->use_opt_stat() &&
OB_FAIL(ctx.get_opt_stat_manager()->get_column_stat(ctx.get_session_info()->get_effective_tenant_id(),
table_meta->get_ref_table_id(),
table_meta->get_all_used_parts(),
column_id,
NULL,
NULL,
NULL,
&column_meta->get_min_value(),
&column_meta->get_max_value(),
&ctx.get_allocator()))) {
LOG_WARN("failed to get column stat", K(ret));
} else {
column_meta->set_min_max_inited(true);
min_obj = column_meta->get_min_value();
max_obj = column_meta->get_max_value();
LOG_TRACE("var basic stat min/max", K(min_obj), K(max_obj));
}
}
}
return ret;
}
int ObOptSelectivity::get_column_hist_scale(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &expr,
double &hist_scale)
{
int ret = OB_SUCCESS;
UNUSED(ctx);
hist_scale = 0.0;
if (OB_UNLIKELY(!expr.is_column_ref_expr())) {
ret = OB_INVALID_ARGUMENT;
LOG_WARN("get invalid expr", K(ret), K(expr));
} else {
const ObColumnRefRawExpr &column_expr = static_cast<const ObColumnRefRawExpr&>(expr);
const OptTableMeta *table_meta = table_metas.get_table_meta_by_table_id(column_expr.get_table_id());
if (OB_NOT_NULL(table_meta)) {
const OptColumnMeta *column_meta = table_meta->get_column_meta(column_expr.get_column_id());
if (OB_ISNULL(column_meta)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("column meta not find", K(ret), K(*table_meta), K(column_expr));
} else {
hist_scale = column_meta->get_hist_scale();
}
}
}
return ret;
}
int ObOptSelectivity::get_column_basic_info(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr &expr,
double *ndv_ptr,
double *num_null_ptr,
double *avg_len_ptr,
double *row_count_ptr)
{
int ret = OB_SUCCESS;
if (OB_UNLIKELY(!expr.is_column_ref_expr())) {
ret = OB_INVALID_ARGUMENT;
LOG_WARN("get invalid expr", K(ret), K(expr));
} else {
const ObColumnRefRawExpr &column_expr = static_cast<const ObColumnRefRawExpr&>(expr);
bool need_default = false;
double ndv = 0;
double num_null = 0;
double avg_len = 0;
double row_count = 0;
if (OB_FAIL(get_column_basic_from_meta(table_metas,
column_expr,
need_default,
row_count,
ndv,
num_null,
avg_len))) {
LOG_WARN("failed to get column basic from meta", K(ret));
} else if (need_default && OB_FAIL(get_var_basic_default(row_count, ndv, num_null, avg_len))) {
LOG_WARN("failed to get var default info", K(ret));
} else {
if (num_null > row_count - ndv) {
num_null = row_count - ndv > 0 ? row_count - ndv : 0;
}
if (ctx.get_current_rows() > 0.0 && ctx.get_current_rows() < row_count) {
ndv = scale_distinct(ctx.get_current_rows(), row_count, ndv);
}
LOG_TRACE("show column basic info", K(row_count), K(ctx.get_current_rows()), K(num_null), K(avg_len), K(ndv));
// set return
assign_value(row_count, row_count_ptr);
assign_value(ndv, ndv_ptr);
assign_value(num_null, num_null_ptr);
assign_value(avg_len, avg_len_ptr);
}
}
return ret;
}
int ObOptSelectivity::get_column_basic_from_meta(const OptTableMetas &table_metas,
const ObColumnRefRawExpr &column_expr,
bool &use_default,
double &row_count,
double &ndv,
double &num_null,
double &avg_len)
{
int ret = OB_SUCCESS;
uint64_t table_id = column_expr.get_table_id();
uint64_t column_id = column_expr.get_column_id();
use_default = false;
const OptTableMeta *table_meta = table_metas.get_table_meta_by_table_id(table_id);
if (OB_NOT_NULL(table_meta)) {
row_count = table_meta->get_rows();
const OptColumnMeta *column_meta = table_meta->get_column_meta(column_id);
if (OB_ISNULL(column_meta)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("column meta not find", K(ret), K(*table_meta), K(column_expr));
} else {
ndv = column_meta->get_ndv();
num_null = column_meta->get_num_null();
avg_len = column_meta->get_avg_len();
}
} else {
use_default = true;
}
return ret;
}
int ObOptSelectivity::get_var_basic_default(double &row_count,
double &ndv,
double &null_num,
double &avg_len)
{
int ret = OB_SUCCESS;
row_count = 1.0;
ndv = 1.0;
null_num = static_cast<double>(row_count * EST_DEF_COL_NULL_RATIO);
avg_len = DEFAULT_COLUMN_SIZE;
return ret;
}
int ObOptSelectivity::get_histogram_by_column(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
uint64_t table_id,
uint64_t column_id,
ObOptColumnStatHandle &column_stat)
{
int ret = OB_SUCCESS;
const OptTableMeta *table_meta = table_metas.get_table_meta_by_table_id(table_id);
if (OB_ISNULL(table_meta) || OB_INVALID_ID == table_meta->get_ref_table_id()) {
// do nothing
} else if (NULL == ctx.get_opt_stat_manager() || !table_meta->use_opt_stat()) {
// do nothing
} else if (table_meta->get_all_used_parts().count() != 1) {
// consider to use the global histogram here
} else if (OB_ISNULL(ctx.get_session_info())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(ctx.get_session_info()));
} else if (OB_FAIL(ctx.get_opt_stat_manager()->get_column_stat(
ctx.get_session_info()->get_effective_tenant_id(),
table_meta->get_ref_table_id(),
table_meta->get_all_used_parts().at(0),
column_id,
column_stat))) {
LOG_WARN("failed to get column stat", K(ret));
}
return ret;
}
int ObOptSelectivity::get_compare_value(const OptSelectivityCtx &ctx,
const ObColumnRefRawExpr *col,
const ObRawExpr *calc_expr,
ObObj &expr_value,
bool &can_cmp)
{
int ret = OB_SUCCESS;
bool type_safe = false;
bool got_result = false;
can_cmp = true;
if (OB_ISNULL(ctx.get_stmt())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("stmt is null", K(ret));
} else if (!calc_expr->is_static_scalar_const_expr()) {
can_cmp = false;
} else if (OB_FAIL(ObRelationalExprOperator::is_equivalent(col->get_result_type(),
col->get_result_type(),
calc_expr->get_result_type(),
type_safe))) {
LOG_WARN("failed to check is type safe", K(ret));
} else if (!type_safe) {
can_cmp = false;
LOG_TRACE("cannot compare column and const using the column type", K(ret));
} else if (OB_FAIL(ObSQLUtils::calc_const_or_calculable_expr(ctx.get_opt_ctx().get_exec_ctx(),
calc_expr,
expr_value,
got_result,
ctx.get_allocator()))) {
LOG_WARN("failed to calc const or calculable expr", K(ret));
} else if (!got_result) {
can_cmp = false;
} else if (expr_value.get_type() != col->get_result_type().get_type() ||
expr_value.get_collation_type() != col->get_result_type().get_collation_type()) {
const ObDataTypeCastParams dtc_params =
ObBasicSessionInfo::create_dtc_params(ctx.get_session_info());
ObObj dest_value;
ObCastCtx cast_ctx(&ctx.get_allocator(),
&dtc_params,
CM_NONE,
col->get_result_type().get_collation_type());
if (OB_FAIL(ObObjCaster::to_type(col->get_result_type().get_type(),
col->get_result_type().get_collation_type(),
cast_ctx,
expr_value,
dest_value))) {
LOG_WARN("failed to cast value", K(ret));
} else {
expr_value = dest_value;
}
}
return ret;
}
/**
* @brief ObOptSelectivity::get_bucket_bound_idx
* find the bucket which satisfy;
* bucket[idx].ev_ <= value < bucket[idx+1].ev_;
*/
int ObOptSelectivity::get_bucket_bound_idx(const ObHistogram &hist,
const ObObj &value,
int64_t &idx,
bool &is_equal)
{
int ret = OB_SUCCESS;
int64_t left = 0;
int64_t right = hist.get_bucket_size() - 1;
idx = -1;
is_equal = false;
if (OB_LIKELY(hist.get_bucket_size() > 0)) {
while (OB_SUCC(ret) && left <= right) {
int64_t mid = (right + left) / 2;
int eq_cmp = 0;
if (OB_FAIL(hist.get(mid).endpoint_value_.compare(value, eq_cmp))) {
LOG_WARN("failed to compare object", K(ret));
} else if (eq_cmp > 0) {
// value < bucket[mid].ev
right = mid - 1;
} else {
// bucket[mid].ev < value
left = mid + 1;
is_equal = is_equal || (0 == eq_cmp);
}
}
if (OB_SUCC(ret)) {
idx = right;
}
}
return ret;
}
/**
* We want to compute the frequence of objs satisfying a equal predicate
*
* for col = value
*
* try to find bucket b[i] which satisfy: b[i].ev <= value
* if b[i].ev == value, then the result is b[i].erc
* else the result is density * sample_size
*
*/
int ObOptSelectivity::get_equal_pred_sel(const ObHistogram &histogram,
const ObObj &value,
const double sample_size_scale,
double &density)
{
int ret = OB_SUCCESS;
int64_t idx = -1;
bool is_equal = false;
const ObObj *new_value = NULL;
ObArenaAllocator tmp_alloc("ObOptSel");
if (OB_FAIL(convert_valid_obj_for_opt_stats(&value, tmp_alloc, new_value))) {
LOG_WARN("failed to convert valid obj for opt stats", K(ret), K(value), KPC(new_value));
} else if (OB_ISNULL(new_value)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(new_value), K(value));
} else if (OB_FAIL(get_bucket_bound_idx(histogram, *new_value, idx, is_equal))) {
LOG_WARN("failed to get bucket bound idx", K(ret));
} else if (idx < 0 || idx >= histogram.get_bucket_size() || !is_equal) {
density = histogram.get_density();
} else {
density = static_cast<double>(histogram.get(idx).endpoint_repeat_count_)
/ histogram.get_sample_size();
}
if (OB_SUCC(ret) && sample_size_scale > 0) {
density /= sample_size_scale;
}
return ret;
}
int ObOptSelectivity::get_range_sel_by_histogram(const ObHistogram &histogram,
const ObQueryRangeArray &ranges,
bool no_whole_range,
const double sample_size_scale,
double &selectivity)
{
int ret = OB_SUCCESS;
selectivity = 0;
for (int64_t i = 0; OB_SUCC(ret) && i < ranges.count(); ++i) {
const ObNewRange *range = ranges.at(i);
double tmp_selectivity = 0;
if (OB_ISNULL(range)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("NULL range", K(ret));
} else if (no_whole_range && range->is_whole_range()) {
tmp_selectivity = DEFAULT_INEQ_SEL;
} else {
const ObRowkey &startkey = range->get_start_key();
const ObRowkey &endkey = range->get_end_key();
if (startkey.get_obj_cnt() == endkey.get_obj_cnt() &&
1 == startkey.get_obj_cnt()) {
const ObObj *startobj = &startkey.get_obj_ptr()[0];
const ObObj *endobj = &endkey.get_obj_ptr()[0];
const ObObj *new_startobj = NULL;
const ObObj *new_endobj = NULL;
ObArenaAllocator tmp_alloc("ObOptSel");
if (OB_FAIL(convert_valid_obj_for_opt_stats(startobj, tmp_alloc, new_startobj)) ||
OB_FAIL(convert_valid_obj_for_opt_stats(endobj, tmp_alloc, new_endobj))) {
LOG_WARN("failed to convert valid obj for opt stats", K(ret), KPC(startobj), KPC(endobj),
KPC(new_startobj), KPC(new_endobj));
} else if (OB_ISNULL(new_startobj) || OB_ISNULL(new_endobj)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(new_startobj), K(new_endobj));
} else if (OB_FAIL(get_range_pred_sel(histogram,
*new_startobj,
range->border_flag_.inclusive_start(),
*new_endobj,
range->border_flag_.inclusive_end(),
tmp_selectivity))) {
LOG_WARN("failed to get range density", K(ret));
} else if (sample_size_scale > 0) {
tmp_selectivity /= sample_size_scale;
}
}
}
if (OB_SUCC(ret)) {
selectivity += tmp_selectivity;
LOG_TRACE("single range histogram selectivity", K(*range), K(tmp_selectivity));
}
}
LOG_TRACE("histogram selectivity", K(ranges), K(selectivity), K(ret));
return ret;
}
/**
* We want to compute the frequencey of objs satisfying a lt/le predicate
*
* I. for col < maxv
* try to find bucket b[i] which satisfy: b[i].ev <= maxv < b[i+1].ev
* if maxv == b[i].ev, then the result would be b[i].enum - b[i].erc
* else (maxv > b[i].ev), then the result would be b[i].enum
*
* II. for col <= maxv
* try to find bucket b[i] which satisfy: b[i].ev <= maxv < b[i+1].ev
* then the result would be b[i].enum
*
* two corner cases exists:
* 1. maxv < b[0].ev, we have no idea how many elements in the first buckets do saitfy obj < maxv
* 2. b[count()-1].ev < maxv, all elements in the histograms satisfy the predicate
*
*/
int ObOptSelectivity::get_less_pred_sel(const ObHistogram &histogram,
const ObObj &maxv,
const bool inclusive,
double &density)
{
int ret = OB_SUCCESS;
int64_t idx = -1;
bool is_equal = false;
if (maxv.is_min_value()) {
density = 0.0;
} else if (maxv.is_max_value()) {
density = 1.0;
} else if (OB_FAIL(get_bucket_bound_idx(histogram, maxv, idx, is_equal))) {
LOG_WARN("failed to get bucket bound idx", K(ret));
} else if (idx < 0) {
density = histogram.get_density();
} else if (idx >= histogram.get_bucket_size()) {
density = 1.0;
} else if (is_equal) {
double frequency = histogram.get(idx).endpoint_num_ -
(inclusive ? 0 : histogram.get(idx).endpoint_repeat_count_);
density = frequency / histogram.get_sample_size();
} else {
double last_bucket_count = 0;
if (idx + 1 < histogram.get_bucket_size()) {
// b[i].ev < maxv < b[i+1].ev
// estimate how many elements (smaller than maxv) in bucket[i+1] there are
ObObj minscalar, maxscalar, startscalar, endscalar;
ObObj minobj(histogram.get(idx).endpoint_value_);
ObObj maxobj(histogram.get(idx+1).endpoint_value_);
ObObj startobj(minobj), endobj(maxv);
if (OB_FAIL(ObOptEstObjToScalar::convert_objs_to_scalars(
&minobj, &maxobj, &startobj, &endobj,
&minscalar, &maxscalar, &startscalar, &endscalar))) {
LOG_WARN("failed to convert objs to scalars", K(ret));
} else if (maxscalar.get_double() - minscalar.get_double() > OB_DOUBLE_EPSINON) {
last_bucket_count = histogram.get(idx+1).endpoint_num_ -
histogram.get(idx+1).endpoint_repeat_count_ -
histogram.get(idx).endpoint_num_;
last_bucket_count *= (endscalar.get_double() - startscalar.get_double()) /
(maxscalar.get_double() - minscalar.get_double());
}
}
density = static_cast<double>(histogram.get(idx).endpoint_num_ + last_bucket_count)
/ histogram.get_sample_size();
}
LOG_TRACE("link bug", K(density), K(maxv), K(inclusive), K(idx), K(is_equal));
return ret;
}
/**
* We want to compute the frequence of objs satisfying a gt/ge predicate
*
* for minv <(=) col
*
* I. f(minv < col) can be converted as sample_size - f(col <= minv)
* II. f(minv <= col) can be converted as sample_size - f(col < minv)
*
*/
int ObOptSelectivity::get_greater_pred_sel(const ObHistogram &histogram,
const ObObj &minv,
const bool inclusive,
double &density)
{
int ret = OB_SUCCESS;
double less_sel = 0;
if (OB_FAIL(get_less_pred_sel(histogram,
minv,
!inclusive,
less_sel))) {
LOG_WARN("failed to get less predicate selectivity", K(ret));
} else {
density = 1.0 - less_sel;
LOG_TRACE("link bug", K(density), K(minv), K(inclusive));
}
return ret;
}
/**
* We want to compute the frequence of objs satisfying a range predicate
*
* for minv <(=) col <(=) maxv
*
* the problem can be converted as f(col <(=) maxv) + f(minv <(=) col) - sample_size
*
*/
int ObOptSelectivity::get_range_pred_sel(const ObHistogram &histogram,
const ObObj &minv,
const bool min_inclusive,
const ObObj &maxv,
const bool max_inclusive,
double &density)
{
int ret = OB_SUCCESS;
double less_sel = 0;
double greater_sel = 0;
if (OB_FAIL(get_greater_pred_sel(histogram, minv, min_inclusive, greater_sel))) {
LOG_WARN("failed to get greater predicate selectivity", K(ret));
} else if (OB_FAIL(get_less_pred_sel(histogram, maxv, max_inclusive, less_sel))) {
LOG_WARN("failed to get less predicate selectivity", K(ret));
} else {
density = less_sel + greater_sel - 1.0;
density = density <= 0 ? histogram.get_density() : density;
}
return ret;
}
int ObOptSelectivity::get_column_query_range(const OptSelectivityCtx &ctx,
const uint64_t table_id,
const uint64_t column_id,
const ObIArray<ObRawExpr *> &quals,
ObIArray<ColumnItem> &column_items,
ObQueryRange &query_range,
ObQueryRangeArray &ranges)
{
int ret = OB_SUCCESS;
const ObLogPlan *log_plan = ctx.get_plan();
const ParamStore *params = ctx.get_params();
ObExecContext *exec_ctx = ctx.get_opt_ctx().get_exec_ctx();
ObIAllocator &allocator = ctx.get_allocator();
ObDataTypeCastParams dtc_params = ObBasicSessionInfo::create_dtc_params(ctx.get_session_info());
const ColumnItem* column_item = NULL;
ObGetMethodArray get_methods;
if (OB_ISNULL(log_plan) || OB_ISNULL(exec_ctx) ||
OB_ISNULL(column_item = log_plan->get_column_item_by_id(table_id, column_id))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(log_plan), K(exec_ctx), K(column_item));
} else if (OB_FAIL(column_items.push_back(*column_item))) {
LOG_WARN("failed to push back column item", K(ret));
} else if (OB_FAIL(query_range.preliminary_extract_query_range(column_items,
quals,
dtc_params,
ctx.get_opt_ctx().get_exec_ctx(),
NULL,
params))) {
LOG_WARN("failed to preliminary extract query range", K(ret));
} else if (!query_range.need_deep_copy()) {
if (OB_FAIL(query_range.get_tablet_ranges(allocator, *exec_ctx, ranges,
get_methods, dtc_params))) {
LOG_WARN("failed to get tablet ranges", K(ret));
}
} else if (OB_FAIL(query_range.final_extract_query_range(*exec_ctx, dtc_params))) {
LOG_WARN("failed to final extract query range", K(ret));
} else if (OB_FAIL(query_range.get_tablet_ranges(ranges, get_methods, dtc_params))) {
LOG_WARN("failed to get tablet ranges", K(ret));
} else { /*do nothing*/ }
return ret;
}
int ObOptSelectivity::check_mutex_or(const ObRawExpr &qual, bool &is_mutex)
{
int ret = OB_SUCCESS;
is_mutex = true;
const ObRawExpr *child_expr = NULL;
const ObRawExpr *column_expr = NULL;
const ObRawExpr *first_column_expr = NULL;
for (int64_t i = 0; OB_SUCC(ret) && is_mutex && i < qual.get_param_count(); ++i) {
if (OB_FAIL(get_simple_mutex_column(qual.get_param_expr(i), column_expr))) {
LOG_WARN("failed to get simple mutex column", K(ret));
} else if (NULL == column_expr) {
is_mutex = false;
} else if (0 == i) {
first_column_expr = column_expr;
} else {
is_mutex = first_column_expr->same_as(*column_expr);
}
}
return ret;
}
// 列上最常见的互斥谓词
// c1 = 1 or c1 = 2
// c1 = 1 or c1 is null
int ObOptSelectivity::get_simple_mutex_column(const ObRawExpr *qual, const ObRawExpr *&column)
{
int ret = OB_SUCCESS;
const ObRawExpr *left_expr = NULL;
const ObRawExpr *right_expr = NULL;
column = NULL;
if (OB_ISNULL(qual)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected NULL", K(ret));
} else if (T_OP_EQ == qual->get_expr_type() ||
T_OP_NSEQ == qual->get_expr_type() ||
T_OP_IS == qual->get_expr_type()) {
if (OB_ISNULL(left_expr = qual->get_param_expr(0)) ||
OB_ISNULL(right_expr = qual->get_param_expr(1))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected NULL", K(ret), K(left_expr), K(right_expr));
} else if (left_expr->is_column_ref_expr() && !right_expr->has_flag(CNT_COLUMN)) {
column = left_expr;
} else if (right_expr->is_column_ref_expr() && !left_expr->has_flag(CNT_COLUMN)) {
column = right_expr;
}
}
return ret;
}
/**
* 算法流程:
* 1. 简化所有的group by表达式, 取出group by中所有的列
* 2. 对于多个列存在于同一个 Equal Set, 只保留 ndv 最小的一个.
* 3. distinct number = ndv(column1) * (ndv(column2) / sqrt(2)) * (ndv(column3) / sqrt(2)) * ...
*/
int ObOptSelectivity::calculate_distinct(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObIArray<ObRawExpr*>& exprs,
const double origin_rows,
double &rows,
const bool need_refine)
{
int ret = OB_SUCCESS;
rows = 1;
// 记录各个列的ndv中的最大值
ObSEArray<ObRawExpr*, 16> column_exprs;
ObSEArray<ObRawExpr*, 16> filtered_exprs;
if (OB_FAIL(ObRawExprUtils::extract_column_exprs(exprs, column_exprs))) {
LOG_WARN("failed to extract all column", K(ret));
} else if (OB_FAIL(filter_column_by_equal_set(table_metas, ctx, column_exprs, filtered_exprs))) {
LOG_WARN("failed filter column by equal set", K(ret));
}
for (int64_t i = 0; OB_SUCC(ret) && i < filtered_exprs.count(); ++i) {
ObRawExpr *column_expr = filtered_exprs.at(i);
double ndv = 0.0;
if (OB_ISNULL(column_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret), K(i));
} else if (OB_FAIL(check_column_in_current_level_stmt(ctx.get_stmt(), *column_expr))) {
LOG_WARN("failed to check column in current level stmt", K(ret));
} else if (OB_FAIL(get_column_basic_info(table_metas, ctx, *column_expr, &ndv, NULL, NULL, NULL))) {
LOG_WARN("failed to get column basic info", K(ret), K(*column_expr));
} else if (0 == i) {
rows *= ndv;
} else {
rows *= ndv / std::sqrt(2);
}
}
if (OB_SUCC(ret) && need_refine) {
rows = std::min(rows, origin_rows);
LOG_TRACE("succeed to calculate distinct", K(origin_rows), K(rows), K(exprs));
}
return ret;
}
// 仅保留一个 ndv 最小的 distinct expr, 加入到 filtered_exprs 中;
// 再把不在 equal set 中的列加入到 filtered_exprs 中,
int ObOptSelectivity::filter_column_by_equal_set(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObIArray<ObRawExpr*> &column_exprs,
ObIArray<ObRawExpr*> &filtered_exprs)
{
int ret = OB_SUCCESS;
const EqualSets *equal_sets = ctx.get_equal_sets();
if (NULL == equal_sets) {
if (OB_FAIL(append(filtered_exprs, column_exprs))) {
LOG_WARN("failed to append filtered exprs", K(ret));
}
} else {
for (int64_t i = 0; OB_SUCC(ret) && i < column_exprs.count(); ++i) {
bool find = false;
double dummy = 0;
ObRawExpr *filtered_expr = NULL;
if (OB_FAIL(get_min_ndv_by_equal_set(table_metas,
ctx,
column_exprs.at(i),
find,
filtered_expr,
dummy))) {
LOG_WARN("failed to find the expr with min ndv", K(ret));
} else if (!find && FALSE_IT(filtered_expr = column_exprs.at(i))) {
// never reach
} else if (OB_FAIL(filtered_exprs.push_back(filtered_expr))) {
LOG_WARN("failed to push back expr", K(ret));
}
}
}
return ret;
}
int ObOptSelectivity::filter_one_column_by_equal_set(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr *column_expr,
const ObRawExpr *&filtered_expr)
{
int ret = OB_SUCCESS;
const EqualSets *equal_sets = ctx.get_equal_sets();
if (NULL == equal_sets) {
filtered_expr = column_expr;
} else {
bool find = false;
double dummy = 0;
ObRawExpr *tmp_expr = NULL;
if (OB_FAIL(get_min_ndv_by_equal_set(table_metas,
ctx,
column_expr,
find,
tmp_expr,
dummy))) {
LOG_WARN("failed to find the expr with min ndv", K(ret));
} else if (!find) {
filtered_expr = column_expr;
} else {
filtered_expr = tmp_expr;
}
}
return ret;
}
/**
* Find the expr_ptr in the eq_sets that is equal to col_expr and has the minimum ndv
*/
int ObOptSelectivity::get_min_ndv_by_equal_set(const OptTableMetas &table_metas,
const OptSelectivityCtx &ctx,
const ObRawExpr *col_expr,
bool &find,
ObRawExpr *&expr,
double &ndv)
{
int ret = OB_SUCCESS;
ObBitSet<> col_added;
find = false;
const EqualSets *eq_sets = ctx.get_equal_sets();
if (OB_ISNULL(eq_sets)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("unexpected null", K(ret));
} else {
for (int64_t i = 0; OB_SUCC(ret) && !find && i < eq_sets->count(); i++) {
const ObRawExprSet *equal_set = eq_sets->at(i);
if (OB_ISNULL(equal_set)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null equal set", K(ret));
} else if (!ObOptimizerUtil::find_item(*equal_set, col_expr)) {
//do nothing
} else {
find = true;
int64_t min_idx = OB_INVALID_INDEX_INT64;
double min_ndv = 0;
for (int64_t k = 0; OB_SUCC(ret) && k < equal_set->count(); ++k) {
double tmp_ndv = 0;
bool is_in = false;
if (OB_ISNULL(equal_set->at(k))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("failed to get column exprs", K(ret));
} else if (!equal_set->at(k)->is_column_ref_expr()) {
//do nothing
} else if (OB_FAIL(column_in_current_level_stmt(ctx.get_stmt(),
*equal_set->at(k),
is_in))) {
LOG_WARN("failed to check column in current level stmt", K(ret));
} else if (!is_in) {
//do nothing
} else if (OB_FAIL(get_column_basic_info(table_metas,
ctx,
*equal_set->at(k),
&tmp_ndv,
NULL,
NULL,
NULL))) {
LOG_WARN("failed to get var basic sel", K(ret));
} else if (OB_INVALID_INDEX_INT64 == min_idx || tmp_ndv < min_ndv) {
min_idx = k;
min_ndv = tmp_ndv;
}
}
if (OB_FAIL(ret)) {
} else if (min_idx < 0 || min_idx >= equal_set->count()) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("unexpect idx", K(min_idx), K(ret));
} else {
expr = equal_set->at(min_idx);
ndv = min_ndv;
}
}
}
}
return ret;
}
/**
* check if multi join condition only related to two table
*/
int ObOptSelectivity::is_valid_multi_join(ObIArray<ObRawExpr *> &quals,
bool &is_valid)
{
int ret = OB_SUCCESS;
is_valid = false;
if (OB_UNLIKELY(quals.count() < 2)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("quals should have more than 1 exprs", K(ret));
} else if (OB_ISNULL(quals.at(0))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else {
const ObRelIds &rel_ids = quals.at(0)->get_relation_ids();
is_valid = rel_ids.num_members() == 2;
for (int64_t i = 1; OB_SUCC(ret) && is_valid && i < quals.count(); ++i) {
ObRawExpr *cur_expr = quals.at(i);
if (OB_ISNULL(cur_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret));
} else if (!rel_ids.equal(cur_expr->get_relation_ids())) {
is_valid = false;
}
}
}
return ret;
}
int ObOptSelectivity::is_columns_contain_pkey(const OptTableMetas &table_metas,
const ObIArray<ObRawExpr *> &col_exprs,
bool &is_pkey,
bool &is_union_pkey)
{
int ret = OB_SUCCESS;
ObSEArray<uint64_t, 4> col_ids;
uint64_t table_id;
if (OB_FAIL(extract_column_ids(col_exprs, col_ids, table_id))) {
LOG_WARN("failed to extract column ids", K(ret));
} else if (OB_FAIL(is_columns_contain_pkey(table_metas, col_ids, table_id, is_pkey, is_union_pkey))) {
LOG_WARN("failed to check is columns contain pkey", K(ret));
}
return ret;
}
int ObOptSelectivity::is_columns_contain_pkey(const OptTableMetas &table_metas,
const ObIArray<uint64_t> &col_ids,
const uint64_t table_id,
bool &is_pkey,
bool &is_union_pkey)
{
int ret = OB_SUCCESS;
is_pkey = true;
is_union_pkey = false;
const OptTableMeta *table_meta = table_metas.get_table_meta_by_table_id(table_id);
if (OB_ISNULL(table_meta)) {
is_pkey = false;
} else if (table_meta->get_pkey_ids().empty()) {
// 没有显式主键, 默认隐式主键不会作为选择条件
is_pkey = false;
} else {
const ObIArray<uint64_t> &pkey_ids = table_meta->get_pkey_ids();
for (int64_t i = 0; is_pkey && i < pkey_ids.count(); ++i) {
bool find = false;
for (int64_t j =0; !find && j < col_ids.count(); ++j) {
if (pkey_ids.at(i) == col_ids.at(j)) {
find = true;
}
}
is_pkey = find;
}
is_union_pkey = pkey_ids.count() > 1;
}
return ret;
}
int ObOptSelectivity::extract_column_ids(const ObIArray<ObRawExpr *> &col_exprs,
ObIArray<uint64_t> &col_ids,
uint64_t &table_id)
{
int ret = OB_SUCCESS;
ObColumnRefRawExpr *column_expr = NULL;
table_id = OB_INVALID_INDEX;
for (int64_t i = 0; OB_SUCC(ret) && i < col_exprs.count(); ++i) {
ObRawExpr *cur_expr = col_exprs.at(i);
if (OB_ISNULL(cur_expr) || OB_UNLIKELY(!cur_expr->is_column_ref_expr())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected expr", K(ret));
} else if (FALSE_IT(column_expr = static_cast<ObColumnRefRawExpr *>(cur_expr))) {
} else if (OB_FAIL(col_ids.push_back(column_expr->get_column_id()))) {
LOG_WARN("failed to push back column id", K(ret));
} else if (0 == i) {
table_id = column_expr->get_table_id();
} else if (OB_UNLIKELY(table_id != column_expr->get_table_id())) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("columns not belong to same table", K(ret), K(*column_expr), K(table_id));
}
}
return ret;
}
int ObOptSelectivity::classify_quals(const ObIArray<ObRawExpr*> &quals,
ObIArray<ObExprSelPair> &all_predicate_sel,
ObIArray<OptSelInfo> &column_sel_infos)
{
int ret = OB_SUCCESS;
const ObRawExpr *qual = NULL;
ObSEArray<ObRawExpr *, 4> column_exprs;
OptSelInfo *sel_info = NULL;
double tmp_selectivity = 1.0;
for (int64_t i = 0; OB_SUCC(ret) && i < quals.count(); ++i) {
column_exprs.reset();
uint64_t column_id = OB_INVALID_ID;
ObColumnRefRawExpr *column_expr = NULL;
if (OB_ISNULL(qual = quals.at(i))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected expr", K(ret));
} else if (OB_FAIL(ObRawExprUtils::extract_column_exprs(qual, column_exprs))) {
LOG_WARN("failed to extract column exprs", K(ret));
} else if (1 == column_exprs.count()) {
column_expr = static_cast<ObColumnRefRawExpr *>(column_exprs.at(0));
column_id = column_expr->get_column_id();
} else {
// use OB_INVALID_ID represent qual contain more than one column
}
if (OB_SUCC(ret) && OB_INVALID_ID != column_id && OB_NOT_NULL(column_expr)) {
sel_info = NULL;
for (int64_t j = 0; j < column_sel_infos.count(); ++j) {
if (column_sel_infos.at(j).column_id_ == column_id) {
sel_info = &column_sel_infos.at(j);
break;
}
}
if (NULL == sel_info) {
if (OB_ISNULL(sel_info = column_sel_infos.alloc_place_holder())) {
ret = OB_ALLOCATE_MEMORY_FAILED;
LOG_WARN("failed to allocate place holder for sel info", K(ret));
} else {
sel_info->column_id_ = column_id;
int64_t offset = 0;
if (ObOptimizerUtil::find_item(all_predicate_sel,
ObExprSelPair(column_expr, 0, true),
&offset)) {
sel_info->range_selectivity_ = all_predicate_sel.at(offset).sel_;
sel_info->has_range_exprs_ = true;
}
}
}
}
if (OB_SUCC(ret) && OB_INVALID_ID != column_id) {
if (OB_LIKELY(get_qual_selectivity(all_predicate_sel, qual, tmp_selectivity))) {
// parse qual and set sel info
sel_info->selectivity_ *= tmp_selectivity;
uint64_t temp_equal_count = 0;
if (OB_FAIL(extract_equal_count(*qual, temp_equal_count))) {
LOG_WARN("failed to extract equal count", K(ret));
} else if (0 == sel_info->equal_count_) {
sel_info->equal_count_ = temp_equal_count;
} else if (temp_equal_count > 0) {
sel_info->equal_count_ = std::min(sel_info->equal_count_, temp_equal_count);
}
} else {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("qual selectivity not find", K(ret));
}
}
}
return ret;
}
bool ObOptSelectivity::get_qual_selectivity(ObIArray<ObExprSelPair> &all_predicate_sel,
const ObRawExpr *qual,
double &selectivity)
{
bool find = false;
selectivity = 1.0;
for (int64_t i = 0; !find && i < all_predicate_sel.count(); ++i) {
if (all_predicate_sel.at(i).expr_ == qual) {
selectivity = all_predicate_sel.at(i).sel_;
find = true;
}
}
return find;
}
// parse qual to get equal condition number
int ObOptSelectivity::extract_equal_count(const ObRawExpr &qual, uint64_t &equal_count)
{
int ret = OB_SUCCESS;
const ObRawExpr *l_expr = NULL;
const ObRawExpr *r_expr = NULL;
if (T_OP_EQ == qual.get_expr_type() || T_OP_NSEQ == qual.get_expr_type()) {
if (OB_ISNULL(l_expr = qual.get_param_expr(0)) || OB_ISNULL(r_expr = qual.get_param_expr(1))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(l_expr), K(r_expr));
} else if ((l_expr->is_column_ref_expr() &&
r_expr->is_const_expr()) ||
(r_expr->is_column_ref_expr() &&
l_expr->is_const_expr())) {
equal_count = 1;
}
} else if (T_OP_IN == qual.get_expr_type()) {
if (OB_ISNULL(l_expr = qual.get_param_expr(0)) || OB_ISNULL(r_expr = qual.get_param_expr(1))) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get unexpected null", K(ret), K(l_expr), K(r_expr));
} else if (l_expr->is_column_ref_expr() && T_OP_ROW == r_expr->get_expr_type()) {
equal_count = r_expr->get_param_count();
}
} else if (T_OP_AND == qual.get_expr_type() || T_OP_OR == qual.get_expr_type()) {
for (int64_t i = 0; OB_SUCC(ret) && i < qual.get_param_count(); ++i) {
uint64_t tmp_equal_count = 0;
const ObRawExpr *child_expr = qual.get_param_expr(i);
if (OB_ISNULL(child_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("get null expr", K(ret));
} else if (OB_FAIL(extract_equal_count(*child_expr, tmp_equal_count))) {
LOG_WARN("failed to extract equal count", K(ret));
} else if (T_OP_AND == qual.get_expr_type()) {
if (0 == equal_count) {
equal_count = tmp_equal_count;
} else if (tmp_equal_count > 0) {
equal_count = std::min(equal_count, tmp_equal_count);
}
} else {
equal_count += tmp_equal_count;
}
}
} else { /* do nothing */ }
return ret;
}
/**
* 此公式参考自 Join Selectivity by Jonathan Lewis.
* 可以理解为 ndv 个值平均分布在原始的行(rows)中, 然后从中选取部分行(selected_rows),
* 公式的结果为选中的行的 non-distinct value (new_ndv).
*/
double ObOptSelectivity::scale_distinct(double selected_rows,
double rows,
double ndv)
{
double new_ndv = ndv;
if (selected_rows > rows) {
// enlarge, ref:
// - http://mysql.taobao.org/monthly/2016/05/09/
// - Haas and Stokes in IBM Research Report RJ 10025
// 根据 partition 信息缩放
// 使用公式 n * d / (n - f1 + f1 * n/N)
// 其中, N(selected_rows) 需要放大到的行数; n(rows) 当前的行数; f1 则是只出现一次的值的数据. 如果假设平均分布, 那么 f1 = d * 2 - n; d 则是 ndv。
//
ndv = (ndv > rows ? rows : ndv); // revise ndv
double f1 = ndv * 2 - rows;
if (f1 > 0) {
new_ndv = (rows * ndv) / (rows - f1 + f1 * rows / selected_rows);
}
} else if (selected_rows < rows) {
// 缩小, 参考 select_without_replacement
if (ndv > OB_DOUBLE_EPSINON && rows > OB_DOUBLE_EPSINON) {
new_ndv = ndv * (1 - std::pow(1 - selected_rows / rows, rows / ndv));
}
}
new_ndv = revise_ndv(new_ndv);
return new_ndv;
}
/**
* compute the number of rows satisfying a equal join predicate `left_column = right_column`
*
* left_hist and right_hist must be frequency histogram
* If is_semi is true, it means this is a semi join predicate.
*
*/
int ObOptSelectivity::get_join_pred_rows(const ObHistogram &left_hist,
const ObHistogram &right_hist,
const bool is_semi,
double &rows)
{
int ret = OB_SUCCESS;
rows = 0;
int64_t lidx = 0;
int64_t ridx = 0;
while (OB_SUCC(ret) && lidx < left_hist.get_bucket_size() && ridx < right_hist.get_bucket_size()) {
int eq_cmp = 0;
if (OB_FAIL(left_hist.get(lidx).endpoint_value_.compare(right_hist.get(ridx).endpoint_value_,
eq_cmp))) {
LOG_WARN("failed to compare histogram endpoint value", K(ret),
K(left_hist.get(lidx).endpoint_value_), K(right_hist.get(ridx).endpoint_value_));
} else if (0 == eq_cmp) {
if (is_semi) {
rows += left_hist.get(lidx).endpoint_repeat_count_;
} else {
rows += left_hist.get(lidx).endpoint_repeat_count_ * right_hist.get(ridx).endpoint_repeat_count_;
}
++lidx;
++ridx;
} else if (eq_cmp > 0) {
// left_endpoint_value > right_endpoint_value
++ridx;
} else {
++lidx;
}
}
return ret;
}
int ObOptSelectivity::convert_valid_obj_for_opt_stats(const ObObj *old_obj,
ObIAllocator &alloc,
const ObObj *&new_obj)
{
int ret = OB_SUCCESS;
if (OB_FAIL(ObOptimizerUtil::truncate_string_for_opt_stats(old_obj,
alloc,
new_obj))) {
LOG_WARN("fail to truncated string", K(ret));
}
LOG_TRACE("Succeed to convert valid obj for opt stats", KPC(old_obj), KPC(new_obj));
return ret;
}
}//end of namespace sql
}//end of namespace oceanbase
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