session.h

/* Copyright (c) 2021 OceanBase and/or its affiliates. All rights reserved.
miniob is licensed under Mulan PSL v2.
You can use this software according to the terms and conditions of the Mulan PSL v2.
You may obtain a copy of Mulan PSL v2 at:
         http://license.coscl.org.cn/MulanPSL2
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 PSL v2 for more details. */
 
//
// Created by Wangyunlai on 2021/5/12.
//
 
#pragma once
 
#include "common/types.h"
#include "common/lang/string.h"
 
class Trx;
class Db;
class SessionEvent;
 
class Session
{
public:
  static Session &default_session();
 
public:
  Session() = default;
  ~Session();
 
  Session(const Session &other);
  void operator=(Session &) = delete;
 
  const char *get_current_db_name() const;
  Db         *get_current_db() const;
 
  void set_current_db(const string &dbname);
 
  void set_trx_multi_operation_mode(bool multi_operation_mode);
 
  bool is_trx_multi_operation_mode() const;
 
  Trx *current_trx();
 
  void destroy_trx();
 
  void set_current_request(SessionEvent *request);
 
  SessionEvent *current_request() const;
 
  void set_sql_debug(bool sql_debug) { sql_debug_ = sql_debug; }
  bool sql_debug_on() const { return sql_debug_; }
 
  void set_hash_join(bool hash_join) { hash_join_ = hash_join; }
  bool hash_join_on() const { return hash_join_; }
 
  void set_use_cascade(bool use_cascade) { use_cascade_ = use_cascade; }
  bool use_cascade() const { return use_cascade_; }
 
  void          set_execution_mode(const ExecutionMode mode) { execution_mode_ = mode; }
  ExecutionMode get_execution_mode() const { return execution_mode_; }
 
  bool used_chunk_mode() { return used_chunk_mode_; }
 
  void set_used_chunk_mode(bool used_chunk_mode) { used_chunk_mode_ = used_chunk_mode; }
 
  static void set_current_session(Session *session);
 
  static Session *current_session();
 
private:
  Db           *db_              = nullptr;
  Trx          *trx_             = nullptr;
  SessionEvent *current_request_ = nullptr;  
 
  bool trx_multi_operation_mode_ = false;  
 
  bool sql_debug_   = false;  
  bool hash_join_   = false;  
  bool use_cascade_ = false;  
 
  // 是否使用了 `chunk_iterator` 模式。 只有在设置了 `chunk_iterator`
  // 并且可以生成相关物理执行计划时才会使用 `chunk_iterator` 模式。
  bool used_chunk_mode_ = false;
 
  ExecutionMode execution_mode_ = ExecutionMode::TUPLE_ITERATOR;
};