/** * 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_REWRITE #include "ob_transform_eliminate_outer_join.h" #include "lib/allocator/ob_allocator.h" #include "lib/oblog/ob_log_module.h" #include "common/ob_common_utility.h" #include "sql/resolver/expr/ob_raw_expr.h" #include "sql/resolver/expr/ob_raw_expr_util.h" #include "sql/resolver/dml/ob_dml_stmt.h" #include "sql/resolver/dml/ob_select_stmt.h" #include "sql/rewrite/ob_transform_utils.h" #include "common/ob_smart_call.h" #include "sql/optimizer/ob_optimizer_util.h" using namespace oceanbase::common; namespace oceanbase { namespace sql { int ObTransformEliminateOuterJoin::transform_one_stmt(common::ObIArray &parent_stmts, ObDMLStmt *&stmt, bool &trans_happened) { int ret = OB_SUCCESS; trans_happened = false; UNUSED(parent_stmts); if (OB_ISNULL(stmt)) { ret = OB_INVALID_ARGUMENT; LOG_WARN("stmt is NULL", K(ret)); } else if (OB_FAIL(eliminate_outer_join(parent_stmts, stmt, trans_happened))) { LOG_WARN("failed to eliminate_outer_join on stmt", K(ret)); } else if (trans_happened) { LOG_TRACE("succeed to eliminate outer join", K(trans_happened)); if (OB_FAIL(add_transform_hint(*stmt))) { LOG_WARN("failed to add transform hint", K(ret)); } } return ret; } int ObTransformEliminateOuterJoin::eliminate_outer_join(ObIArray &parent_stmts, ObDMLStmt *&stmt, bool &trans_happened) { int ret = OB_SUCCESS; ObSEArray conditions; trans_happened = false; if (OB_ISNULL(stmt)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("stmt should not be null", K(ret)); } else if (stmt->get_joined_tables().empty()) { /*do nothing*/ } else if (OB_FAIL(stmt->get_equal_set_conditions(conditions, true))) { LOG_WARN("failed to get equal set conditions", K(ret)); } else if (OB_FAIL(get_extra_condition_from_parent(parent_stmts, stmt, conditions))) { LOG_WARN("failed to get null reject select", K(ret)); } else { common::ObArray from_item_list; common::ObArray joined_table_list; // do transform in from items ObIArray &items = stmt->get_from_items(); for (int64_t i = 0; OB_SUCC(ret) && i < items.count(); ++i) { ret = recursive_eliminate_outer_join_in_table_item(stmt, stmt->get_table_item(items.at(i)), from_item_list, joined_table_list, conditions, true, trans_happened); } //after trans, reset table item if (OB_SUCC(ret)) { if (OB_FAIL(stmt->reset_from_item(from_item_list))) { LOG_WARN("failed to reset table_items", K(ret)); } else if (OB_FAIL(stmt->get_joined_tables().assign(joined_table_list))) { LOG_WARN("failed to reset joined table container", K(ret)); } else { LOG_TRACE("succ to to do outer join elimination"); } } } return ret; } int ObTransformEliminateOuterJoin::recursive_eliminate_outer_join_in_table_item(ObDMLStmt *stmt, TableItem *cur_table_item, common::ObIArray &from_item_list, common::ObIArray &joined_table_list, ObIArray &conditions, bool should_move_to_from_list, bool &trans_happened) { int ret = OB_SUCCESS; bool is_stack_overflow = false; bool is_my_joined_table_type = false; JoinedTable *process_join = NULL; if (OB_ISNULL(cur_table_item) || OB_ISNULL(stmt)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("param has null", K(ret)); } else if (OB_FAIL(check_stack_overflow(is_stack_overflow))) { LOG_WARN("failed to check stack overflow", K(ret)); } else if (is_stack_overflow) { ret = OB_SIZE_OVERFLOW; LOG_WARN("too deep recursive", K(ret), K(is_stack_overflow)); } else if (OB_FAIL(is_outer_joined_table_type(stmt, cur_table_item, from_item_list, joined_table_list, should_move_to_from_list, is_my_joined_table_type))) { LOG_WARN("check joined table type failed", K(ret)); } else if (is_my_joined_table_type) { OPT_TRACE("try to eliminate joined table:", cur_table_item); //子表无法从stmt中查找，只能通过指针转换得到joined_table process_join = static_cast(cur_table_item); bool is_happened = false; ret = do_eliminate_outer_join(stmt, process_join, from_item_list, joined_table_list, conditions, should_move_to_from_list, is_happened); //继续处理左右子表 if (OB_SUCC(ret)) { trans_happened |= is_happened; bool child_should_move_to_from_list = is_happened && should_move_to_from_list && INNER_JOIN == process_join->joined_type_; TableItem *l_child = process_join->left_table_; TableItem *r_child = process_join->right_table_; ObSEArray left_child_conditions; if (OB_FAIL(append_array_no_dup(left_child_conditions, conditions))) { LOG_WARN("failed to append array no dup.", K(ret)); } else if (process_join->joined_type_ == INNER_JOIN && OB_FAIL(append_array_no_dup(left_child_conditions, process_join->join_conditions_))) { LOG_WARN("failed to append array no dup.", K(ret)); } else if (OB_FAIL(SMART_CALL(recursive_eliminate_outer_join_in_table_item(stmt, l_child, from_item_list, joined_table_list, left_child_conditions, child_should_move_to_from_list, trans_happened)))) { LOG_WARN("failed to process the left child", K(ret), K(r_child)); } else { ObSEArray right_child_conditions; if (OB_FAIL(append_array_no_dup(right_child_conditions, conditions))) { LOG_WARN("failed to append array no dup.", K(ret)); } else if (process_join->joined_type_ != FULL_OUTER_JOIN && process_join->joined_type_ != CONNECT_BY_JOIN && OB_FAIL(append_array_no_dup(right_child_conditions, process_join->join_conditions_))) { LOG_WARN("failed to append array no dup.", K(ret)); } else if (OB_FAIL(SMART_CALL(recursive_eliminate_outer_join_in_table_item(stmt, r_child, from_item_list, joined_table_list, right_child_conditions, child_should_move_to_from_list, trans_happened)))) { LOG_WARN("failed to process the right child", K(ret), K(r_child)); } else { /*do nothing*/ } } } else { /*do nothing*/ } } else { /*do nothing*/ } return ret; } int ObTransformEliminateOuterJoin::is_outer_joined_table_type(ObDMLStmt *stmt, TableItem *cur_table_item, common::ObIArray &from_item_list, common::ObIArray &joined_table_list, bool should_move_to_from_list, bool &is_my_joined_table_type) { int ret = OB_SUCCESS; JoinedTable *cur_joined_table_item = NULL; is_my_joined_table_type = false; if (OB_ISNULL(stmt) || OB_ISNULL(cur_table_item)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("param has null", K(ret)); } else if (!cur_table_item->is_joined_table()) { if (should_move_to_from_list) { //非joined table不处理，直接放入from_item_list FromItem from_item; from_item.is_joined_ = false; from_item.table_id_ = cur_table_item->table_id_; if (OB_FAIL(from_item_list.push_back(from_item))) { LOG_WARN("failed to push to from item list", K(ret)); } else { /* do nothing */ } } else { /*do nothing*/ } } else { cur_joined_table_item = static_cast(cur_table_item); if (OB_ISNULL(cur_joined_table_item)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("table item should not be null", K(ret)); } else if (LEFT_OUTER_JOIN == cur_joined_table_item->joined_type_ || FULL_OUTER_JOIN == cur_joined_table_item->joined_type_ || INNER_JOIN == cur_joined_table_item->joined_type_ || CONNECT_BY_JOIN == cur_joined_table_item->joined_type_) { //仅处理left join、full join、inner join、connect by的左右table item is_my_joined_table_type = true; } else { if (should_move_to_from_list) { FromItem from_item; from_item.is_joined_ = true; from_item.table_id_ = cur_table_item->table_id_; if (OB_FAIL(from_item_list.push_back(from_item))) { LOG_WARN("failed to push to from item list", K(ret)); } else if (OB_FAIL(joined_table_list.push_back(cur_joined_table_item))) { LOG_WARN("failed to push to joined table list", K(ret)); } else { /* do nothing */ } } else { /*do nothing*/ } } } return ret; } int ObTransformEliminateOuterJoin::do_eliminate_outer_join(ObDMLStmt *stmt, JoinedTable *cur_joined_table, common::ObIArray &from_item_list, common::ObIArray &joined_table_list, ObIArray &conditions, bool should_move_to_from_list, bool &trans_happened) { int ret = OB_SUCCESS; bool can_eliminate = false; if (OB_ISNULL(stmt) || OB_ISNULL(cur_joined_table) || OB_ISNULL(cur_joined_table->left_table_) || OB_ISNULL(cur_joined_table->right_table_)) { ret = OB_INVALID_ARGUMENT; LOG_WARN("param has null", K(ret)); } else { if (FULL_OUTER_JOIN == cur_joined_table->joined_type_) { //是否能消除左外连接 if (OB_FAIL(can_be_eliminated(stmt, cur_joined_table, conditions, can_eliminate))) { LOG_WARN("failed to test eliminated left join condition", K(ret)); } else if (can_eliminate) { //left join消除后，旋转right join为左连接 trans_happened = true; TableItem* temp = cur_joined_table->left_table_; cur_joined_table->left_table_ = cur_joined_table->right_table_; cur_joined_table->right_table_ = temp; cur_joined_table->joined_type_ = LEFT_OUTER_JOIN; } else { //left join不能消除，旋转连接，尝试消除right join TableItem* temp = cur_joined_table->left_table_; cur_joined_table->left_table_ = cur_joined_table->right_table_; cur_joined_table->right_table_ = temp; } if (OB_SUCC(ret)) { //尝试消除right join旋转后转换的left join if (OB_FAIL(can_be_eliminated(stmt, cur_joined_table, conditions, can_eliminate))) { LOG_WARN("failed to test eliminated right join condition", K(ret)); } else if (can_eliminate) { trans_happened = true; if (cur_joined_table->joined_type_ == LEFT_OUTER_JOIN) { cur_joined_table->joined_type_ = INNER_JOIN; } else { TableItem* temp = cur_joined_table->left_table_; cur_joined_table->left_table_ = cur_joined_table->right_table_; cur_joined_table->right_table_ = temp; cur_joined_table->joined_type_ = LEFT_OUTER_JOIN; } } else { if (cur_joined_table->joined_type_ == FULL_OUTER_JOIN) { //还原旋转 TableItem* temp = cur_joined_table->left_table_; cur_joined_table->left_table_ = cur_joined_table->right_table_; cur_joined_table->right_table_ = temp; } else { /*do nothing*/ } } } else { /*do nothing*/ } } else if (LEFT_OUTER_JOIN == cur_joined_table->joined_type_) { //是否能消除左外连接 if (OB_FAIL(can_be_eliminated(stmt, cur_joined_table, conditions, can_eliminate))) { LOG_WARN("failed to test eliminated left join condition", K(ret)); } else if (can_eliminate) { trans_happened = true; cur_joined_table->joined_type_ = INNER_JOIN; } else { /*do nothing*/ } } else { /*do nothing for inner join or connect by join*/ } if (OB_SUCC(ret)) { //外连接被消除了 if (INNER_JOIN == cur_joined_table->joined_type_) { if (should_move_to_from_list) { trans_happened = true; if (OB_FAIL(stmt->add_condition_exprs(cur_joined_table->join_conditions_))) { LOG_WARN("failed to move join conditions into where clause", K(ret)); } else if (OB_FAIL(append_array_no_dup(conditions, cur_joined_table->join_conditions_))) { LOG_WARN("failed to append conditions.", K(ret)); } else { /* do nothing. */ } } else { /*do nothing*/ } } else if (should_move_to_from_list) { // 最后一个最顶层，需要加入from_item_list和joined_table_list FromItem from_item; from_item.is_joined_ = true; from_item.table_id_ = cur_joined_table->table_id_; if (OB_FAIL(from_item_list.push_back(from_item))) { LOG_WARN("faled to push back origin from item", K(ret)); } else if (OB_FAIL(joined_table_list.push_back(cur_joined_table))) { LOG_WARN("faield to push back origin joined item", K(ret)); } else { /* do nothing. */ } } else { /*do nothing*/ } } else { /*do nothing*/ } } return ret; } int ObTransformEliminateOuterJoin::can_be_eliminated(ObDMLStmt *stmt, JoinedTable *joined_table, ObIArray &conditions, bool &can_eliminate) { int ret = OB_SUCCESS; if (OB_FAIL(can_be_eliminated_with_null_reject(stmt, joined_table, conditions, can_eliminate))) { LOG_WARN("failed to test eliminated condition with null reject", K(ret)); } else if (can_eliminate) { /*do nothing*/ } else if (OB_FAIL(can_be_eliminated_with_foreign_primary_join(stmt, joined_table, conditions, can_eliminate))) { LOG_WARN("failed to test eliminated condition with foreign primary join", K(ret)); } else if (can_eliminate) { /*do nothing*/ } else if (OB_FAIL(can_be_eliminated_with_null_side_column_in_aggr(stmt, joined_table, can_eliminate))) { LOG_WARN("failed to test eliminated condition with aggr null column", K(ret)); } else { /*do nothing*/ } if (OB_SUCC(ret)) { OPT_TRACE("joined table will be eliminated:", can_eliminate); } return ret; } int ObTransformEliminateOuterJoin::can_be_eliminated_with_null_reject(ObDMLStmt *stmt, JoinedTable *joined_table, ObIArray &conditions, bool &has_null_reject) { int ret = OB_SUCCESS; const TableItem *right_table; ObSEArray col_exprs; ObSqlBitSet<> right_table_ids; has_null_reject = false; if (OB_ISNULL(stmt) || OB_ISNULL(joined_table)) { ret = OB_INVALID_ARGUMENT; LOG_WARN("params have null", K(ret), K(stmt), K(joined_table)); } else if (INNER_JOIN == joined_table->joined_type_) { has_null_reject = true; OPT_TRACE("inner join will be eliminated"); } else if (OB_ISNULL(right_table = joined_table->right_table_)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("right table is null", K(ret)); } else if (OB_FAIL(stmt->get_table_rel_ids(*(joined_table->right_table_), right_table_ids))) { LOG_WARN("failed to get right table relation ids", K(ret)); } // check whether any condition is null reject for any column of the right table for (int64_t i = 0; OB_SUCC(ret) && !has_null_reject && i < conditions.count(); ++i) { col_exprs.reuse(); ObRawExpr *condition = conditions.at(i); if (OB_FAIL(extract_columns(condition, right_table_ids, col_exprs))) { LOG_WARN("failed to extract columns", K(ret)); } else if (OB_FAIL(ObTransformUtils::is_null_reject_condition(condition, col_exprs, has_null_reject))) { LOG_WARN("failed to check whether the condition is null rejection", K(ret)); } else if (has_null_reject) { OPT_TRACE("joined table eliminated by", condition); } } if (!has_null_reject) { OPT_TRACE("there is no null reject condition, joined table will not be eliminated"); } return ret; } int ObTransformEliminateOuterJoin::can_be_eliminated_with_foreign_primary_join(ObDMLStmt *stmt, JoinedTable *joined_table, ObIArray &conditions, bool &can_eliminate) { int ret = OB_SUCCESS; ObSEArray left_col_exprs, right_col_exprs; ObSqlBitSet<> left_table_ids; ObSqlBitSet<> right_table_ids; bool is_foreign_primary_join = false; bool is_first_table_parent = false; bool is_all_foreign_columns_not_null = false; bool is_simple_condition = false; bool is_foreign_rely = false; share::schema::ObForeignKeyInfo *foreign_key_info = NULL; can_eliminate = false; if (OB_ISNULL(stmt) || OB_ISNULL(ctx_) || OB_ISNULL(joined_table) || OB_ISNULL(joined_table->left_table_) || OB_ISNULL(joined_table->right_table_)) { ret = OB_INVALID_ARGUMENT; LOG_WARN("params have null", K(ret), K(stmt), K(joined_table)); } else if (INNER_JOIN == joined_table->joined_type_) { can_eliminate = true; OPT_TRACE("inner join will be eliminated"); } else if (!joined_table->left_table_->is_basic_table() || !joined_table->right_table_->is_basic_table()) { /*do nothing*/ } else if (OB_FAIL(is_simple_join_condition(joined_table->join_conditions_, joined_table->left_table_, joined_table->right_table_, is_simple_condition))) { LOG_WARN("check is simple join condition failed", K(ret)); } else if (!is_simple_condition) { /*on condition不是简单的列相等连接，不能消除，do nothing*/ OPT_TRACE("on condition is not simply join condition"); } else if (OB_FAIL(stmt->get_table_rel_ids(*(joined_table->left_table_),left_table_ids))) { LOG_WARN("failed to get left table rel ids", K(ret)); } else if (OB_FAIL(stmt->get_table_rel_ids(*(joined_table->right_table_), right_table_ids))) { LOG_WARN("failed to get right table relation ids", K(ret)); } else if (OB_FAIL(extract_columns_from_join_conditions(joined_table->join_conditions_, left_table_ids, left_col_exprs))) { LOG_WARN("failed to extract columns", K(ret)); } else if (OB_FAIL(extract_columns_from_join_conditions(joined_table->join_conditions_, right_table_ids, right_col_exprs))) { LOG_WARN("failed to extract columns", K(ret)); } else if(left_col_exprs.count() != right_col_exprs.count() ) { /*do nothing*/ } else if (OB_FAIL(ObTransformUtils::check_foreign_primary_join(joined_table->left_table_, joined_table->right_table_, left_col_exprs, right_col_exprs, ctx_->schema_checker_, ctx_->session_info_, is_foreign_primary_join, is_first_table_parent, foreign_key_info))) { LOG_WARN("failed to check foreign primary join", K(ret)); } else if (!is_foreign_primary_join || is_first_table_parent) { /*不是主外键连接，或者外键表不是左表，不能消除，do nothing*/ OPT_TRACE("not foreign primary join"); } else if (OB_FAIL(ObTransformUtils::is_foreign_key_rely(ctx_->session_info_, foreign_key_info, is_foreign_rely))) { LOG_WARN("can not get foreign key info", K(ret)); } else if (!is_foreign_rely) { /*非可靠主外键关系，不能消除，do nothing*/ OPT_TRACE("foreign key is not rely"); } else if (OB_UNLIKELY(!joined_table->right_table_->access_all_part())) { /*右表有partition hint，不可消除*/ /*TODO zhenling.zzg 之后可以完善对于父表、子表均有partition hint的情况*/ OPT_TRACE("right table has parition hint"); } else if (OB_FAIL(is_all_columns_not_null(stmt, left_col_exprs, conditions, is_all_foreign_columns_not_null))) { LOG_WARN("check foreign columns is not null failed", K(ret)); } else if (is_all_foreign_columns_not_null) { can_eliminate = true; } else { can_eliminate = false; OPT_TRACE("foreign key has null columns"); } return ret; } int ObTransformEliminateOuterJoin::is_all_columns_not_null(ObDMLStmt *stmt, const ObIArray &col_exprs, ObIArray &conditions, bool &is_not_null) { int ret = OB_SUCCESS; is_not_null = false; if (OB_ISNULL(stmt) || OB_ISNULL(ctx_)) { ret = OB_INVALID_ARGUMENT; LOG_WARN("stmt is null", K(ret)); } else { //是否外键所有列都有非空约束 bool is_nullable = false; bool has_null_reject = false; const ObRawExpr *col_expr = NULL; for (int64_t i = 0; OB_SUCC(ret) && !is_nullable && i < col_exprs.count(); ++i) { if (OB_ISNULL(col_expr = col_exprs.at(i)) || OB_UNLIKELY(!col_expr->is_column_ref_expr())) { ret = OB_ERR_UNEXPECTED; LOG_WARN("unexpected column ref expr", K(ret), K(col_expr)); } else if (OB_FAIL(ObTransformUtils::is_column_nullable(stmt, ctx_->schema_checker_, static_cast(col_expr), ctx_->session_info_, is_nullable))) { LOG_WARN("check column is not null failed", K(ret)); } else if (!is_nullable) { /*do nothing*/ } else if (OB_FAIL(ObTransformUtils::has_null_reject_condition(conditions, col_expr, has_null_reject))) { LOG_WARN("failed to check whether the condition is null rejection", K(ret)); } else { is_nullable = !has_null_reject; } } if (is_nullable) {//不是所有外键列都有非空约束 is_not_null = false; } else { is_not_null = true; } } return ret; } int ObTransformEliminateOuterJoin::is_simple_join_condition(const ObIArray &join_condition, const TableItem* left_table, const TableItem* right_table, bool &is_simple) { int ret = OB_SUCCESS; is_simple = true; for (int64_t i = 0; OB_SUCC(ret) && is_simple && i < join_condition.count(); ++i) { ObRawExpr *expr = join_condition.at(i); if (OB_ISNULL(expr)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("expr is null", K(ret)); } else if (T_OP_EQ == expr->get_expr_type()) { ObOpRawExpr *op = static_cast(expr); if (OB_ISNULL(op)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("op expr is null", K(ret)); } else if (OB_ISNULL(op->get_param_expr(0)) || OB_ISNULL(op->get_param_expr(1))) { ret = OB_ERR_UNEXPECTED; LOG_WARN("EQ expr has null param", K(ret)); } else if (op->get_param_expr(0)->has_flag(IS_COLUMN) && op->get_param_expr(1)->has_flag(IS_COLUMN)) { ObColumnRefRawExpr *col1 = static_cast(op->get_param_expr(0)); ObColumnRefRawExpr *col2 = static_cast(op->get_param_expr(1)); if ((col1->get_table_id() == left_table->table_id_ && col2->get_table_id() == right_table->table_id_) || (col1->get_table_id() == right_table->table_id_ && col2->get_table_id() == left_table->table_id_)) { /*do nothing*/ } else { is_simple = false; } } else { is_simple = false; } } else { is_simple = false; } } return ret; } int ObTransformEliminateOuterJoin::extract_columns(const ObRawExpr *expr, const ObSqlBitSet<> &rel_ids, common::ObIArray &col_exprs) { int ret = OB_SUCCESS; bool is_stack_overflow = false; if (OB_ISNULL(expr)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("expr is null", K(ret)); } else if (OB_FAIL(check_stack_overflow(is_stack_overflow))) { LOG_WARN("failed to check stack overflow", K(ret)); } else if (is_stack_overflow) { ret = OB_SIZE_OVERFLOW; LOG_WARN("too deep recursive", K(ret), K(is_stack_overflow)); } else if (expr->is_column_ref_expr()) { if (rel_ids.is_superset(expr->get_relation_ids())) { if (OB_FAIL(col_exprs.push_back(static_cast(expr)))) { LOG_WARN("failed to push back col expr", K(ret)); } else {/*do nothing*/} } else {/*do nothing*/} } else if (expr->has_flag(CNT_COLUMN)) { for (int64_t i = 0; OB_SUCC(ret) && i < expr->get_param_count(); ++i) { if (OB_FAIL(SMART_CALL(extract_columns(expr->get_param_expr(i), rel_ids, col_exprs)))) { LOG_WARN("failed to extract columns from param", K(ret)); } else {/*do nothing*/} } } else {/*do nothing*/} return ret; } int ObTransformEliminateOuterJoin::extract_columns_from_join_conditions(const ObIArray &exprs, const ObSqlBitSet<> &rel_ids, common::ObIArray &col_exprs) { int ret = OB_SUCCESS; for (int64_t i = 0; OB_SUCC(ret) && i < exprs.count(); ++i) { if (OB_FAIL(extract_columns(exprs.at(i), rel_ids, col_exprs))) { LOG_WARN("extract columns failed", K(ret)); } else { /*do nothing*/ } } return ret; } int ObTransformEliminateOuterJoin::get_extra_condition_from_parent(ObIArray &parent_stmts, ObDMLStmt *&stmt, ObIArray &conditions) { int ret = OB_SUCCESS; bool has_rownum = false; ObDMLStmt *parent_stmt = NULL; TableItem *table_item = NULL; if (parent_stmts.empty()) { // do nothing } else if (OB_ISNULL(stmt)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("get unexpected null", K(ret)); } else if (OB_FAIL(stmt->has_rownum(has_rownum))) { LOG_WARN("failed to check stmt has rownum", K(ret)); } else if (stmt->has_limit() || stmt->has_sequence() || has_rownum) { // do nothing } else if (OB_ISNULL(parent_stmt = parent_stmts.at(parent_stmts.count() - 1).stmt_)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("get unexpected null", K(ret)); } else if (OB_FAIL(ObTransformUtils::get_generated_table_item(*parent_stmt, stmt, table_item))) { LOG_WARN("failed to get table_item", K(ret)); } else if (OB_NOT_NULL(table_item)) { ObSEArray table_columns; ObSEArray all_conditions; bool has_null_reject = false; ObColumnRefRawExpr *col = NULL; ObRawExpr *select_expr = NULL; if (OB_FAIL(parent_stmt->get_column_exprs(table_item->table_id_, table_columns))) { LOG_WARN("failed to get column exprs", K(ret)); } else if (OB_FAIL(ObTransformUtils::get_table_related_condition(*parent_stmt, table_item, all_conditions))) { LOG_WARN("failed to get table related condition", K(ret)); } else if (OB_LIKELY(stmt->is_select_stmt())) { ObSelectStmt *child_stmt = static_cast(stmt); for (int64_t i = 0; OB_SUCC(ret) && i < table_columns.count(); ++i) { if (OB_ISNULL(col = table_columns.at(i))) { ret = OB_ERR_UNEXPECTED; LOG_WARN("get unexpected null", K(ret)); } else if (OB_UNLIKELY(col->get_column_id() < 16 || col->get_column_id() - 16 >= child_stmt->get_select_item_size())) { ret = OB_ERR_UNEXPECTED; LOG_WARN("get unexpected view column", K(ret), K(*col)); } else if (OB_ISNULL(select_expr = child_stmt->get_select_item(col->get_column_id() - 16).expr_)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("get unexpected null", K(ret)); } else if (select_expr->has_flag(CNT_AGG) || select_expr->has_flag(CNT_WINDOW_FUNC) || select_expr->has_flag(CNT_SUB_QUERY)) { // do nothing } else if (OB_FAIL(ObTransformUtils::has_null_reject_condition(all_conditions, col, has_null_reject))) { LOG_WARN("faield to check has null reject condition", K(ret)); } else if (has_null_reject && OB_FAIL(conditions.push_back(select_expr))) { LOG_WARN("failed to push back expr", K(ret)); } } } } return ret; } int ObTransformEliminateOuterJoin::can_be_eliminated_with_null_side_column_in_aggr(ObDMLStmt *stmt, JoinedTable *joined_table, bool &can_eliminate) { int ret= OB_SUCCESS; ObSelectStmt* select_stmt = NULL; can_eliminate = false; ObSqlBitSet<> right_table_ids; TableItem* right_table = NULL; ObSEArray right_col_exprs; if (OB_ISNULL(stmt) || OB_ISNULL(joined_table) || OB_ISNULL(ctx_)) { ret = OB_INVALID_ARGUMENT; LOG_WARN("params have null", K(ret), K(stmt), K(joined_table)); } else if (!stmt->is_select_stmt()) { /*do nothing*/ } else if (OB_FALSE_IT(select_stmt = static_cast(stmt))) { /*do nothing*/ } else if (!select_stmt->is_scala_group_by()) { /*do nothing*/ } else if (!joined_table->is_left_join()) { /*do nothing*/ } else if (OB_ISNULL(right_table = joined_table->right_table_)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("get right join item failed", K(ret)); } else if (OB_FAIL(stmt->get_table_rel_ids(*right_table, right_table_ids))) { LOG_WARN("failed to get right table relation ids", K(ret)); } else { can_eliminate = true; if (!is_only_full_group_by_on(ctx_->session_info_->get_sql_mode())) { for (int64_t i = 0; OB_SUCC(ret) && can_eliminate && i < select_stmt->get_select_item_size(); ++i) { if (OB_FAIL(check_expr_ref_column_all_in_aggr(select_stmt->get_select_item(i).expr_, can_eliminate))) { LOG_WARN("check expr ref column all in aggr failed", K(ret)); } } } for (int64_t i = 0; OB_SUCC(ret) && can_eliminate && i < select_stmt->get_aggr_item_size(); ++i) { ObAggFunRawExpr *aggr_expr = select_stmt->get_aggr_item(i); right_col_exprs.reuse(); if (OB_ISNULL(aggr_expr)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("expr is null", K(ret)); } else if (aggr_expr->get_expr_type() != T_FUN_COUNT && aggr_expr->get_expr_type() != T_FUN_MIN && aggr_expr->get_expr_type() != T_FUN_MAX && aggr_expr->get_expr_type() != T_FUN_SUM) { can_eliminate = false; } else if (!aggr_expr->has_flag(CNT_COLUMN)) { can_eliminate = false; } else if (OB_FAIL(extract_columns(aggr_expr, right_table_ids, right_col_exprs))) { LOG_WARN("failed to extract columns", K(ret)); } else { for (int64_t param_index = 0; OB_SUCC(ret) && can_eliminate && param_index < aggr_expr->get_real_param_count(); param_index++) { if (OB_FAIL(ObTransformUtils::is_null_propagate_expr(aggr_expr->get_real_param_exprs().at(param_index), right_col_exprs, can_eliminate))) { LOG_WARN("failed to call is_null_propagate_expr", K(ret)); } } } } } return ret; } int ObTransformEliminateOuterJoin::check_expr_ref_column_all_in_aggr(const ObRawExpr *expr, bool &is_in) { int ret = OB_SUCCESS; is_in = true; if (OB_ISNULL(expr)) { ret = OB_ERR_UNEXPECTED; LOG_WARN("expr is null", K(ret)); } else if (expr->is_column_ref_expr()) { is_in = false; } else if (expr->is_aggr_expr()) { // do nothing } else if (expr->has_flag(CNT_COLUMN)) { for (int64_t i = 0; OB_SUCC(ret) && is_in && i < expr->get_param_count(); ++i) { if (OB_FAIL(SMART_CALL(check_expr_ref_column_all_in_aggr(expr->get_param_expr(i), is_in)))) { LOG_WARN("failed to check expr ref column all in aggr", K(ret)); } } } return ret; } }//namespace sql }//namespace oceanbase