64 lines
2.2 KiB
C++
64 lines
2.2 KiB
C++
/**
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* Copyright (c) 2021 OceanBase
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* OceanBase CE is licensed under Mulan PubL v2.
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* You can use this software according to the terms and conditions of the Mulan PubL v2.
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* You may obtain a copy of Mulan PubL v2 at:
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* http://license.coscl.org.cn/MulanPubL-2.0
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* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
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* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
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* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
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* See the Mulan PubL v2 for more details.
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*/
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#ifndef OB_TRANSFORM_SIMPLIFY_LIMIT_H
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#define OB_TRANSFORM_SIMPLIFY_LIMIT_H
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#include "sql/rewrite/ob_transform_rule.h"
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namespace oceanbase {
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namespace sql {
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class ObTransformSimplifyLimit : public ObTransformRule
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{
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public:
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ObTransformSimplifyLimit(ObTransformerCtx *ctx)
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: ObTransformRule(ctx, TransMethod::POST_ORDER,
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T_SIMPLIFY_LIMIT)
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{}
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virtual ~ObTransformSimplifyLimit() {}
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virtual int transform_one_stmt(common::ObIArray<ObParentDMLStmt> &parent_stmts,
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ObDMLStmt *&stmt,
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bool &trans_happened) override;
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private:
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int add_limit_to_semi_right_table(ObDMLStmt *stmt,
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bool &trans_happened);
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int check_need_add_limit_to_semi_right_table(ObDMLStmt *stmt,
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SemiInfo *semi_info,
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bool &need_add);
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int pushdown_limit_offset(ObDMLStmt *stmt,
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bool &trans_happened);
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int check_pushdown_limit_offset_validity(ObSelectStmt *upper_stmt,
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ObSelectStmt *&view_stmt,
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bool &is_valid);
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int do_pushdown_limit_offset(ObSelectStmt *upper_stmt,
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ObSelectStmt *view_stmt);
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int pushdown_limit_order_for_union(ObDMLStmt *stmt, bool& trans_happened);
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int check_can_pushdown_limit_order(ObSelectStmt& upper_stmt,
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ObSelectStmt*& view_stmt,
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bool& can_push);
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int do_pushdown_limit_order_for_union(ObSelectStmt& upper_stmt, ObSelectStmt* view_stmt);
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};
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}
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}
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#endif // OB_TRANSFORM_SIMPLIFY_LIMIT_H
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