Train debug (#203)

### What problem were solved in this pull request?

Problem:
与训练营配合，可以在SQL命令请求过程中，添加调试信息

### What is changed and how it works?
可以参考 debug-output.md 文档。
增加 sql_debug 变量，使用set sql_debug=1; 可以设置。
在SQL命令执行过程中，调用sql_debug函数，增加调试信息。在普通文本通讯协议中，调试信息会以 '#'
开头的形式打印出来。但是注意调试信息中不要带换行符。

### Other information

.vscode/launch.json

@@ -9,7 +9,7 @@
             "request": "launch",
             "name": "Debug",
             "program": "${workspaceFolder}/${defaultBuildTask}/bin/observer",
-            "args": ["-f", "${workspaceFolder}/etc/observer.ini", "-s", "miniob.sock"],
+            "args": ["-f", "${workspaceFolder}/etc/observer.ini", "-P", "cli"],
             "cwd": "${workspaceFolder}/${defaultBuildTask}/"
         }
     ]

build.sh

@@ -5,7 +5,7 @@ TOPDIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
 
 BUILD_SH=$TOPDIR/build.sh
 
-CMAKE_COMMAND="cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=1"
+CMAKE_COMMAND="cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=1 --log-level=WARNING"
 
 ALL_ARGS=("$@")
 BUILD_ARGS=()
@@ -73,38 +73,40 @@ function do_init
   git submodule update --init || return
   current_dir=$PWD
 
+  MAKE_COMMAND="make --silent"
+
   # build libevent
   cd ${TOPDIR}/deps/3rd/libevent && \
     git checkout release-2.1.12-stable && \
     mkdir -p build && \
     cd build && \
-    cmake .. -DEVENT__DISABLE_OPENSSL=ON -DEVENT__LIBRARY_TYPE=BOTH && \
-    make -j4 && \
+    ${CMAKE_COMMAND} .. -DEVENT__DISABLE_OPENSSL=ON -DEVENT__LIBRARY_TYPE=BOTH && \
+    ${MAKE_COMMAND} -j4 && \
     make install
 
   # build googletest
   cd ${TOPDIR}/deps/3rd/googletest && \
     mkdir -p build && \
     cd build && \
-    cmake .. && \
-    make -j4 && \
-    make install
+    ${CMAKE_COMMAND} .. && \
+    ${MAKE_COMMAND} -j4 && \
+    ${MAKE_COMMAND} install
 
   # build google benchmark
   cd ${TOPDIR}/deps/3rd/benchmark && \
     mkdir -p build && \
     cd build && \
-    cmake .. -DBENCHMARK_ENABLE_TESTING=OFF  -DBENCHMARK_INSTALL_DOCS=OFF -DBENCHMARK_ENABLE_GTEST_TESTS=OFF -DBENCHMARK_USE_BUNDLED_GTEST=OFF -DBENCHMARK_ENABLE_ASSEMBLY_TESTS=OFF && \
-    make -j4 && \
-    make install
+    ${CMAKE_COMMAND} .. -DBENCHMARK_ENABLE_TESTING=OFF  -DBENCHMARK_INSTALL_DOCS=OFF -DBENCHMARK_ENABLE_GTEST_TESTS=OFF -DBENCHMARK_USE_BUNDLED_GTEST=OFF -DBENCHMARK_ENABLE_ASSEMBLY_TESTS=OFF && \
+    ${MAKE_COMMAND} -j4 && \
+    ${MAKE_COMMAND} install
 
   # build jsoncpp
   cd ${TOPDIR}/deps/3rd/jsoncpp && \
     mkdir -p build && \
     cd build && \
-    cmake -DJSONCPP_WITH_TESTS=OFF -DJSONCPP_WITH_POST_BUILD_UNITTEST=OFF .. && \
-    make && \
-    make install
+    ${CMAKE_COMMAND} -DJSONCPP_WITH_TESTS=OFF -DJSONCPP_WITH_POST_BUILD_UNITTEST=OFF .. && \
+    ${MAKE_COMMAND} && \
+    ${MAKE_COMMAND} install
 
   cd $current_dir
 }

deps/common/log/log.h

@@ -25,15 +25,13 @@ See the Mulan PSL v2 for more details. */
 #include <map>
 #include <set>
 #include <string>
-#include  <functional>
+#include <functional>
 
 #include "common/defs.h"
 
 namespace common {
 
 const unsigned int ONE_KILO = 1024;
-const unsigned int ONE_MILLION = ONE_KILO * ONE_KILO;
-const unsigned int ONE_GIGA = ONE_MILLION * ONE_KILO;
 const unsigned int FILENAME_LENGTH_MAX = 256;  // the max filename length
 
 const int LOG_STATUS_OK = 0;
@@ -111,6 +109,11 @@ public:
 
   int rotate(const int year = 0, const int month = 0, const int day = 0);
 
+  /**
+   * @brief 设置一个在日志中打印当前上下文信息的回调函数
+   * @details 比如设置一个获取当前session标识的函数，那么每次在打印日志时都会输出session信息。
+   *          这个回调函数返回了一个intptr_t类型的数据，可能返回字符串更好，但是现在够用了。
+   */
   void set_context_getter(std::function<intptr_t()> context_getter);
   intptr_t context_id();
   
@@ -328,13 +331,4 @@ int Log::out(const LOG_LEVEL console_level, const LOG_LEVEL log_level, T &msg)
  */
 const char *lbt();
 
-/**
- * @brief 设置一个在日志中打印当前上下文信息的回调函数
- * @details 比如设置一个获取当前session标识的函数，那么每次在打印日志时都会输出session信息。
- *          这个回调函数返回了一个intptr_t类型的数据，可能返回字符串更好，但是现在够用了。
- */
-void set_log_context_getter(std::function<intptr_t()> context_getter);
-
-extern std::function<intptr_t()> g_context_getter;
-
 }  // namespace common

docs/src/design/miniob-transaction.md

 本篇文档介绍 MiniOB 中的事务模块是如何工作的。
 
 # 背景
-事务是数据库中非常基础的一个模块，也是非常核心的功能。事务有一些基本的概念，叫做ACID，分别是原子性(Atomicity)、一致性(Consistency)、隔离性(Isolation)和持久性(Durability)。如果你对事务的基本概念不太清楚，建议先学习了解事务的基本概念，比如学习[事务处理](lectures/lecture-6.md)章节，或者在网上搜索更多资料。
+事务是数据库中非常基础的一个模块，也是非常核心的功能。事务有一些基本的概念，叫做ACID，分别是原子性(Atomicity)、一致性(Consistency)、隔离性(Isolation)和持久性(Durability)。如果你对事务的基本概念不太清楚，建议先学习了解事务的基本概念，比如学习[事务处理](../lectures/lecture-6.md)章节，或者在网上搜索更多资料。
 
 # MiniOB 中的事务
 ## 实现简介

docs/src/game/debug-output.md

+本篇文档介绍如何向[训练营](https://open.oceanbase.com/train)输出调试信息。
+
+在使用训练营提交测试时，有时候会遇到本地环境没有问题，但是训练营上的输出总是不符合预期。但是训练营没有办法调试，这时候就需要在训练营上输出调试信息，以便于定位问题。
+
+**如何输出调试信息**
+
+可以参考文件 `sql_debug.h`，在需要输出调试信息的地方，调用`sql_debug`函数即可。sql_debug 的使用与打印日志类似，不过可以在向客户端输出正常结果后，再输出调试信息。
+执行`sql_debug`同时会在日志中打印DEBUG级别的日志。
+
+**示例**
+
+1. `CreateTableStmt::create`
+2. `TableScanPhysicalOperator::next`
+
+**注意**
+由于训练营上能够容纳的信息有限，所以输出太多信息会被截断。
+
+**开关**
+
+每个连接都可以开启或关闭调试，可以参考 `Session::sql_debug_`。
+
+在交互式命令行中，可以使用 `set sql_debug=1` 开启调试，使用 `set sql_debug=0` 关闭调试。
+
+> 当前没有实现查看变量的命令。
+
+示例
+
+```bash
+miniob > select * from t;
+id
+1
+
+# get a tuple: 1
+miniob > set sql_debug=0;
+SUCCESS
+miniob > select * from t;
+id
+1
+
+```
\ No newline at end of file

docs/src/game/introduction.md

@@ -21,6 +21,9 @@
 训练营的使用方法比较简单，不过这里也有一个小手册：
 [训练营使用手册](https://ask.oceanbase.com/t/topic/35600372)
 
+为了方便大家使用训练营时获取调试信息，这里有一个小手册：
+[训练营调试输出手册](./debug-output.md)
+
 注意，在训练营开始前，需要注意自己的程序输出需要满足一定的要求，请参考：
 [提交测试需要满足的输出要求](./miniob-output-convention.md)
 

src/observer/common/ini_setting.h

@@ -20,7 +20,7 @@ See the Mulan PSL v2 for more details. */
 #define MAX_CONNECTION_NUM "MAX_CONNECTION_NUM"
 #define MAX_CONNECTION_NUM_DEFAULT 8192
 #define PORT "PORT"
-#define PORT_DEFAULT 16880
+#define PORT_DEFAULT 6789
 
 #define SOCKET_BUFFER_SIZE 8192
 

src/observer/common/rc.h

@@ -71,6 +71,8 @@ See the Mulan PSL v2 for more details. */
   DEFINE_RC(FILE_SEEK)                      \
   DEFINE_RC(FILE_READ)                      \
   DEFINE_RC(FILE_WRITE)                     \
+  DEFINE_RC(VARIABLE_NOT_EXISTS)            \
+  DEFINE_RC(VARIABLE_NOT_VALID)             \
   DEFINE_RC(LOGBUF_FULL)
 
 enum class RC

src/observer/event/session_event.h

@@ -19,10 +19,15 @@ See the Mulan PSL v2 for more details. */
 
 #include "common/seda/stage_event.h"
 #include "sql/executor/sql_result.h"
+#include "event/sql_debug.h"
 
 class Session;
 class Communicator;
 
+/**
+ * @brief 表示一个SQL请求
+ * 
+ */
 class SessionEvent : public common::StageEvent 
 {
 public:
@@ -32,23 +37,17 @@ public:
   Communicator *get_communicator() const;
   Session *session() const;
 
-  void set_query(const std::string &query)
-  {
-    query_ = query;
-  }
+  void set_query(const std::string &query) { query_ = query; }
 
-  const std::string &query() const
-  {
-    return query_;
-  }
-  SqlResult *sql_result()
-  {
-    return &sql_result_;
-  }
+  const std::string &query() const { return query_; }
 
-private:
-  Communicator *communicator_ = nullptr;
-  SqlResult     sql_result_;
+  SqlResult *sql_result() { return &sql_result_; }
+
+  SqlDebug &sql_debug() { return sql_debug_; }
 
-  std::string   query_;
+private:
+  Communicator *communicator_ = nullptr;  ///< 与客户端通讯的对象
+  SqlResult     sql_result_;  ///< SQL执行结果
+  SqlDebug      sql_debug_; ///< SQL调试信息
+  std::string   query_; ///< SQL语句
 };

src/observer/event/sql_debug.cpp

+/* 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 2023/6/29.
+//
+
+#include <stdarg.h>
+
+#include "event/sql_debug.h"
+#include "session/session.h"
+#include "event/session_event.h"
+
+using namespace std;
+
+void SqlDebug::add_debug_info(const std::string &debug_info)
+{
+  debug_infos_.push_back(debug_info);
+}
+
+void SqlDebug::clear_debug_info()
+{
+  debug_infos_.clear();
+}
+
+const list<string> &SqlDebug::get_debug_infos() const
+{
+  return debug_infos_;
+}
+
+void sql_debug(const char *fmt, ...)
+{
+  Session *session  = Session::current_session();
+  if (nullptr == session) {
+    return;
+  }
+
+  SessionEvent *request = session->current_request();
+  if (nullptr == request) {
+    return ;
+  }
+
+  SqlDebug &sql_debug = request->sql_debug();
+
+  const int buffer_size = 4096;
+  char *str = new char[buffer_size];
+
+  va_list ap;
+  va_start(ap, fmt);
+  vsnprintf(str, buffer_size, fmt, ap);
+  va_end(ap);
+
+  sql_debug.add_debug_info(str);
+  LOG_DEBUG("sql debug info: %s", str);
+
+  delete[] str;
+}

src/observer/event/sql_debug.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 2023/6/29.
+//
+
+#pragma once
+
+#include <list>
+#include <string>
+
+/**
+ * @brief SQL调试信息
+ * @details 
+ * 希望在运行SQL时，可以直接输出一些调试信息到客户端。
+ * 当前把调试信息都放在了session上，可以随着SQL语句输出。
+ * 但是现在还不支持与输出调试信息与行数据同步输出。
+ */
+class SqlDebug
+{
+public:
+  SqlDebug() = default;
+  virtual ~SqlDebug() = default;
+
+  void add_debug_info(const std::string &debug_info);
+  void clear_debug_info();
+
+  const std::list<std::string> &get_debug_infos() const;
+
+private:
+  std::list<std::string> debug_infos_;
+};
+
+/**
+ * @brief 增加SQL的调试信息
+ * @details 可以在任何执行SQL语句时调用这个函数来增加调试信息。
+ * 如果当前上下文不在SQL执行过程中，那么不会生成调试信息。
+ * 在普通文本场景下，调试信息会直接输出到客户端，并增加 '#' 作为前缀。
+ */
+void sql_debug(const char *fmt, ...);

src/observer/event/sql_event.h

@@ -23,6 +23,9 @@ class SessionEvent;
 class Stmt;
 class Command;
 
+/**
+ * @brief 与SessionEvent类似，也是处理SQL请求的事件，只是用在SQL的不同阶段
+ */
 class SQLStageEvent : public common::StageEvent
 {
 public:
@@ -74,8 +77,8 @@ public:
 
 private:
   SessionEvent *session_event_ = nullptr;
-  std::string sql_;
-  std::unique_ptr<Command> command_;
-  Stmt *stmt_ = nullptr;
-  std::unique_ptr<PhysicalOperator> operator_;
+  std::string sql_;  ///< 处理的SQL语句
+  std::unique_ptr<Command> command_;  ///< 语法解析后的SQL命令
+  Stmt *stmt_ = nullptr;  ///< Resolver之后生成的数据结构
+  std::unique_ptr<PhysicalOperator> operator_; ///< 生成的执行计划，也可能没有
 };

src/observer/net/mysql_communicator.cpp

@@ -973,9 +973,7 @@ RC MysqlCommunicator::send_result_rows(SqlResult *sql_result, bool no_column_def
         break;  // TODO send error packet
       }
 
-      std::stringstream ss;
-      value.to_string(ss);
-      pos += store_lenenc_string(buf + pos, ss.str().c_str());
+      pos += store_lenenc_string(buf + pos, value.to_string().c_str());
     }
 
     int payload_length = pos - 4;

src/observer/net/plain_communicator.cpp

@@ -23,6 +23,9 @@ See the Mulan PSL v2 for more details. */
 PlainCommunicator::PlainCommunicator()
 {
   send_message_delimiter_.assign(1, '\0');
+  debug_message_prefix_.resize(2);
+  debug_message_prefix_[0] = '#';
+  debug_message_prefix_[1] = ' ';
 }
 
 RC PlainCommunicator::read_event(SessionEvent *&event)
@@ -113,42 +116,67 @@ RC PlainCommunicator::write_state(SessionEvent *event, bool &need_disconnect)
   need_disconnect = false;
   delete[] buf;
 
-  writer_->flush();
   return RC::SUCCESS;
 }
 
-RC PlainCommunicator::write_result(SessionEvent *event, bool &need_disconnect)
+RC PlainCommunicator::write_debug(SessionEvent *request, bool &need_disconnect)
 {
-  need_disconnect = true;
-
-  SqlResult *sql_result = event->sql_result();
-  if (nullptr == sql_result) {
-
-    const char *response = "Unexpected error: no result";
-    int len = strlen(response);
+  if (!session_->sql_debug_on()) {
+    return RC::SUCCESS;
+  }
 
-    RC rc = writer_->writen(response, len);
+  SqlDebug &sql_debug = request->sql_debug();
+  const std::list<std::string> &debug_infos = sql_debug.get_debug_infos();
+  for (auto &debug_info : debug_infos) {
+    RC rc = writer_->writen(debug_message_prefix_.data(), debug_message_prefix_.size());
     if (OB_FAIL(rc)) {
-      LOG_ERROR("Failed to send data back to client. ret=%s, error=%s", strrc(rc), strerror(errno));
+      LOG_WARN("failed to send data to client. err=%s", strerror(errno));
+      need_disconnect = true;
+      return RC::IOERR_WRITE;
+    }
 
-      return rc;
+    rc = writer_->writen(debug_info.data(), debug_info.size());
+    if (OB_FAIL(rc)) {
+      LOG_WARN("failed to send data to client. err=%s", strerror(errno));
+      need_disconnect = true;
+      return RC::IOERR_WRITE;
     }
 
-    rc = writer_->writen(send_message_delimiter_.data(), send_message_delimiter_.size());
+    char newline = '\n';
+    rc = writer_->writen(&newline, 1);
     if (OB_FAIL(rc)) {
-      LOG_ERROR("Failed to send data back to client. ret=%s, error=%s", strrc(rc), strerror(errno));
-      return rc;
+      LOG_WARN("failed to send new line to client. err=%s", strerror(errno));
+      need_disconnect = true;
+      return RC::IOERR_WRITE;
     }
+  }
 
-    need_disconnect = false;
-    return RC::SUCCESS;
+  need_disconnect = false;
+  return RC::SUCCESS;
+}
+
+RC PlainCommunicator::write_result(SessionEvent *event, bool &need_disconnect)
+{
+  RC rc = write_result_internal(event, need_disconnect);
+  if (!need_disconnect) {
+    (void)write_debug(event, need_disconnect);
   }
+  writer_->flush(); // TODO handle error
+  return rc;
+}
+
+RC PlainCommunicator::write_result_internal(SessionEvent *event, bool &need_disconnect)
+{
+  RC rc = RC::SUCCESS;
+  need_disconnect = true;
+
+  SqlResult *sql_result = event->sql_result();
 
   if (RC::SUCCESS != sql_result->return_code() || !sql_result->has_operator()) {
     return write_state(event, need_disconnect);
   }
 
-  RC rc = sql_result->open();
+  rc = sql_result->open();
   if (OB_FAIL(rc)) {
     sql_result->close();
     sql_result->set_return_code(rc);
@@ -215,9 +243,7 @@ RC PlainCommunicator::write_result(SessionEvent *event, bool &need_disconnect)
         return rc;
       }
 
-      std::stringstream ss;
-      value.to_string(ss);
-      std::string cell_str = ss.str();
+      std::string cell_str = value.to_string();
       rc = writer_->writen(cell_str.data(), cell_str.size());
       if (OB_FAIL(rc)) {
         LOG_WARN("failed to send data to client. err=%s", strerror(errno));
@@ -266,6 +292,5 @@ RC PlainCommunicator::write_result(SessionEvent *event, bool &need_disconnect)
     rc = rc_close;
   }
 
-  writer_->flush(); // TODO handle error
   return rc;
 }
\ No newline at end of file

src/observer/net/plain_communicator.h

@@ -34,7 +34,10 @@ public:
 
 private:
   RC write_state(SessionEvent *event, bool &need_disconnect);
+  RC write_debug(SessionEvent *event, bool &need_disconnect);
+  RC write_result_internal(SessionEvent *event, bool &need_disconnect);
 
 protected:
   std::vector<char> send_message_delimiter_; ///< 发送消息分隔符
+  std::vector<char> debug_message_prefix_; ///< 调试信息前缀
 };

src/observer/session/session.cpp

@@ -90,3 +90,13 @@ Session *Session::current_session()
 {
   return thread_session;
 }
+
+void Session::set_current_request(SessionEvent *request)
+{
+  current_request_ = request;
+}
+
+SessionEvent *Session::current_request() const
+{
+  return current_request_;
+}

src/observer/session/session.h

@@ -18,11 +18,19 @@ See the Mulan PSL v2 for more details. */
 
 class Trx;
 class Db;
+class SessionEvent;
 
+/**
+ * @brief 表示会话
+ * @details 当前一个连接一个会话，没有做特殊的会话管理，这也简化了会话处理
+ */
 class Session 
 {
 public:
-  // static Session &current();
+  /**
+   * @brief 获取默认的会话数据，新生成的会话都基于默认会话设置参数
+   * @note 当前并没有会话参数
+   */
   static Session &default_session();
 
 public:
@@ -35,18 +43,58 @@ public:
   const char *get_current_db_name() const;
   Db *get_current_db() const;
 
+  /**
+   * @brief 设置当前会话关联的数据库
+   * 
+   * @param dbname 数据库名字
+   */
   void set_current_db(const std::string &dbname);
 
+  /**
+   * @brief 设置当前事务为多语句模式，需要明确的指出提交或回滚
+   */
   void set_trx_multi_operation_mode(bool multi_operation_mode);
+
+  /**
+   * @brief 当前事务是否为多语句模式
+   */
   bool is_trx_multi_operation_mode() const;
 
+  /**
+   * @brief 当前会话关联的事务
+   * 
+   */
   Trx *current_trx();
 
+  /**
+   * @brief 设置当前正在处理的请求
+   */
+  void set_current_request(SessionEvent *request);
+
+  /**
+   * @brief 获取当前正在处理的请求
+   */
+  SessionEvent *current_request() const;
+
+  void set_sql_debug(bool sql_debug) { sql_debug_ = sql_debug; }
+  bool sql_debug_on() const { return sql_debug_; }
+
+  /**
+   * @brief 将指定会话设置到线程变量中
+   * 
+   */
   static void set_current_session(Session *session);
+
+  /**
+   * @brief 获取当前的会话
+   * @details 当前某个请求开始时，会将会话设置到线程变量中，在整个请求处理过程中不会改变
+   */
   static Session *current_session();
   
 private:
   Db *db_ = nullptr;
   Trx *trx_ = nullptr;
-  bool trx_multi_operation_mode_ = false;  // 当前事务的模式，是否多语句模式. 单语句模式自动提交
+  SessionEvent *current_request_ = nullptr; ///< 当前正在处理的请求
+  bool trx_multi_operation_mode_ = false;   ///< 当前事务的模式，是否多语句模式. 单语句模式自动提交
+  bool sql_debug_ = false;                  ///< 是否输出SQL调试信息
 };

src/observer/session/session_stage.cpp

@@ -116,6 +116,7 @@ void SessionStage::handle_request(StageEvent *event)
   }
 
   Session::set_current_session(sev->session());
+  sev->session()->set_current_request(sev);
   SQLStageEvent *sql_event = new SQLStageEvent(sev, sql);
   query_cache_stage_->handle_event(sql_event);
 
@@ -126,5 +127,6 @@ void SessionStage::handle_request(StageEvent *event)
   if (need_disconnect) {
     Server::close_connection(communicator);
   }
+  sev->session()->set_current_request(nullptr);
   Session::set_current_session(nullptr);
 }

src/observer/sql/executor/command_executor.cpp

@@ -22,6 +22,7 @@ See the Mulan PSL v2 for more details. */
 #include "sql/executor/show_tables_executor.h"
 #include "sql/executor/trx_begin_executor.h"
 #include "sql/executor/trx_end_executor.h"
+#include "sql/executor/set_variable_executor.h"
 #include "common/log/log.h"
 
 RC CommandExecutor::execute(SQLStageEvent *sql_event)
@@ -65,6 +66,11 @@ RC CommandExecutor::execute(SQLStageEvent *sql_event)
       return executor.execute(sql_event);
     }
 
+    case StmtType::SET_VARIABLE: {
+      SetVariableExecutor executor;
+      return executor.execute(sql_event);
+    }
+
     case StmtType::EXIT: {
       return RC::SUCCESS;
     }

src/observer/sql/executor/desc_table_executor.cpp

@@ -29,6 +29,7 @@ using namespace std;
 
 RC DescTableExecutor::execute(SQLStageEvent *sql_event)
 {
+  RC rc = RC::SUCCESS;
   Stmt *stmt = sql_event->stmt();
   SessionEvent *session_event = sql_event->session_event();
   Session *session = session_event->session();
@@ -65,5 +66,5 @@ RC DescTableExecutor::execute(SQLStageEvent *sql_event)
     sql_result->set_return_code(RC::SCHEMA_TABLE_NOT_EXIST);
     sql_result->set_state_string("Table not exists");
   }
-  return RC::SCHEMA_TABLE_NOT_EXIST;
+  return rc;
 }
\ No newline at end of file

src/observer/sql/executor/execute_stage.h

@@ -26,7 +26,7 @@ class SelectStmt;
  * @brief 执行SQL语句的Stage，包括DML和DDL
  * @ingroup SQLStage
  * @details 根据前面阶段生成的结果，有些语句会生成执行计划，有些不会。
- * 整体上分为两类，带执行计划的，或者 @class CommandExecutor 可以直接执行的。
+ * 整体上分为两类，带执行计划的，或者 CommandExecutor 可以直接执行的。
  */
 class ExecuteStage : public common::Stage 
 {

src/observer/sql/executor/set_variable_executor.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 2023/6/14.
+//
+
+#pragma once
+
+#include "common/rc.h"
+#include "sql/operator/string_list_physical_operator.h"
+#include "event/sql_event.h"
+#include "event/session_event.h"
+#include "sql/executor/sql_result.h"
+#include "session/session.h"
+#include "sql/stmt/set_variable_stmt.h"
+
+/**
+ * @brief SetVariable语句执行器
+ * @ingroup Executor
+ */
+class SetVariableExecutor
+{
+public:
+  SetVariableExecutor() = default;
+  virtual ~SetVariableExecutor() = default;
+
+  RC execute(SQLStageEvent *sql_event)
+  {
+    RC rc = RC::SUCCESS;
+    Session *session = sql_event->session_event()->session();
+    SetVariableStmt *stmt = (SetVariableStmt *)sql_event->stmt();
+
+    const char *var_name = stmt->var_name();
+    const Value &var_value = stmt->var_value();
+    if (strcasecmp(var_name, "sql_debug") == 0) {
+      bool bool_value = false;
+      rc = var_value_to_boolean(var_value, bool_value);
+      if (rc != RC::SUCCESS) {
+        return rc;
+      }
+
+      session->set_sql_debug(bool_value);
+      LOG_TRACE("set sql_debug to %d", bool_value);
+    } else {
+      rc = RC::VARIABLE_NOT_EXISTS;
+    }
+
+    return RC::SUCCESS;
+  }
+
+private:
+  RC var_value_to_boolean(const Value &var_value, bool &bool_value) const
+  {
+    RC rc = RC::SUCCESS;
+
+    if (var_value.attr_type() == AttrType::BOOLEANS) {
+      bool_value = var_value.get_boolean();
+    } else if (var_value.attr_type() == AttrType::INTS) {
+      bool_value = var_value.get_int() != 0;
+    } else if (var_value.attr_type() == AttrType::FLOATS) {
+      bool_value = var_value.get_float() != 0.0;
+    } else if (var_value.attr_type() == AttrType::CHARS) {
+
+      std::string true_strings[] = {
+          "true",
+          "on",
+          "yes",
+          "t",
+          "1"
+      };
+
+      std::string false_strings[] = {
+          "false",
+          "off",
+          "no",
+          "f",
+          "0"
+      };
+
+      for (size_t i = 0; i < sizeof(true_strings) / sizeof(true_strings[0]); i++) {
+        if (strcasecmp(var_value.get_string().c_str(), true_strings[i].c_str()) == 0) {
+          bool_value = true;
+          return rc;
+        }
+      }
+
+      for (size_t i = 0; i < sizeof(false_strings) / sizeof(false_strings[0]); i++) {
+        if (strcasecmp(var_value.get_string().c_str(), false_strings[i].c_str()) == 0) {
+          bool_value = false;
+          return rc;
+        }
+      }
+      rc = RC::VARIABLE_NOT_VALID;
+    }
+
+    return rc;
+  }
+};
\ No newline at end of file

src/observer/sql/executor/sql_result.h

@@ -24,7 +24,8 @@ class Session;
 
 /**
  * @brief SQL执行结果
- * @details 如果当前SQL生成了执行计划，那么在返回客户端时，调用执行计划返回结果。
+ * @details 
+ * 如果当前SQL生成了执行计划，那么在返回客户端时，调用执行计划返回结果。
  * 否则返回的结果就是当前SQL的执行结果，比如DDL语句，通过return_code和state_string来描述。
  * 如果出现了一些错误，也可以通过return_code和state_string来获取信息。
  */

src/observer/sql/expr/tuple.h

@@ -16,6 +16,7 @@ See the Mulan PSL v2 for more details. */
 
 #include <memory>
 #include <vector>
+#include <string>
 
 #include "common/log/log.h"
 #include "sql/expr/tuple_cell.h"
@@ -26,6 +27,27 @@ See the Mulan PSL v2 for more details. */
 
 class Table;
 
+/**
+ * @defgroup Tuple
+ * @brief Tuple 元组，表示一行数据，当前返回客户端时使用
+ * @details 
+ * tuple是一种可以嵌套的数据结构。
+ * 比如select t1.a+t2.b from t1, t2;
+ * 需要使用下面的结构表示：
+ * @code {.cpp}
+ *  Project(t1.a+t2.b)
+ *        |
+ *      Joined
+ *      /     \
+ *   Row(t1) Row(t2)
+ * @endcode
+ * 
+ */
+
+/**
+ * @brief 元组的结构，包含哪些字段(这里成为Cell)，每个字段的说明
+ * @ingroup Tuple
+ */
 class TupleSchema 
 {
 public:
@@ -54,17 +76,63 @@ private:
   std::vector<TupleCellSpec> cells_;
 };
 
+/**
+ * @brief 元组的抽象描述
+ * @ingroup Tuple
+ */
 class Tuple 
 {
 public:
   Tuple() = default;
   virtual ~Tuple() = default;
 
+  /**
+   * @brief 获取元组中的Cell的个数
+   * @details 个数应该与tuple_schema一致
+   */
   virtual int cell_num() const = 0;
+
+  /**
+   * @brief 获取指定位置的Cell
+   * 
+   * @param index 位置
+   * @param[out] cell  返回的Cell
+   */
   virtual RC cell_at(int index, Value &cell) const = 0;
+
+  /**
+   * @brief 根据cell的描述，获取cell的值
+   * 
+   * @param spec cell的描述
+   * @param[out] cell 返回的cell
+   */
   virtual RC find_cell(const TupleCellSpec &spec, Value &cell) const = 0;
+
+  virtual std::string to_string() const
+  {
+    std::string str;
+    const int cell_num = this->cell_num();
+    for (int i = 0; i < cell_num - 1; i++) {
+      Value cell;
+      cell_at(i, cell);
+      str += cell.to_string();
+      str += ", ";
+    }
+
+    if (cell_num > 0) {
+      Value cell;
+      cell_at(cell_num - 1, cell);
+      str += cell.to_string();
+    }
+    return str;
+  }
 };
 
+/**
+ * @brief 一行数据的元组
+ * @ingroup Tuple
+ * @details 直接就是获取表中的一条记录
+ */
 class RowTuple : public Tuple 
 {
 public:
@@ -156,6 +224,13 @@ private:
   std::vector<FieldExpr *> speces_;
 };
 
+/**
+ * @brief 从一行数据中，选择部分字段组成的元组，也就是投影操作
+ * @ingroup Tuple
+ * @details 一般在select语句中使用。
+ * 投影也可以是很复杂的操作，比如某些字段需要做类型转换、重命名、表达式运算、函数计算等。
+ * 当前的实现是比较简单的，只是选择部分字段，不做任何其他操作。
+ */
 class ProjectTuple : public Tuple 
 {
 public:
@@ -215,6 +290,10 @@ private:
   Tuple *tuple_ = nullptr;
 };
 
+/**
+ * @brief 一些常量值组成的Tuple
+ * @ingroup Tuple
+ */
 class ValueListTuple : public Tuple 
 {
 public:
@@ -251,8 +330,9 @@ private:
 };
 
 /**
- * 将两个tuple合并为一个tuple
- * 在join算子中使用
+ * @brief 将两个tuple合并为一个tuple
+ * @ingroup Tuple
+ * @details 在join算子中使用
  */
 class JoinedTuple : public Tuple 
 {
@@ -274,28 +354,28 @@ public:
     return left_->cell_num() + right_->cell_num();
   }
 
-  RC cell_at(int index, Value &cell) const override
+  RC cell_at(int index, Value &value) const override
   {
     const int left_cell_num = left_->cell_num();
     if (index > 0 && index < left_cell_num) {
-      return left_->cell_at(index, cell);
+      return left_->cell_at(index, value);
     }
 
     if (index >= left_cell_num && index < left_cell_num + right_->cell_num()) {
-      return right_->cell_at(index - left_cell_num, cell);
+      return right_->cell_at(index - left_cell_num, value);
     }
 
     return RC::NOTFOUND;
   }
 
-  RC find_cell(const TupleCellSpec &spec, Value &cell) const override
+  RC find_cell(const TupleCellSpec &spec, Value &value) const override
   {
-    RC rc = left_->find_cell(spec, cell);
+    RC rc = left_->find_cell(spec, value);
     if (rc == RC::SUCCESS || rc != RC::NOTFOUND) {
       return rc;
     }
 
-    return right_->find_cell(spec, cell);
+    return right_->find_cell(spec, value);
   }
 
 private:

src/observer/sql/operator/table_scan_physical_operator.cpp

@@ -14,6 +14,7 @@ See the Mulan PSL v2 for more details. */
 
 #include "sql/operator/table_scan_physical_operator.h"
 #include "storage/table/table.h"
+#include "event/sql_debug.h"
 
 using namespace std;
 
@@ -48,8 +49,10 @@ RC TableScanPhysicalOperator::next()
     }
 
     if (filter_result) {
+      sql_debug("get a tuple: %s", tuple_.to_string().c_str());
       break;
     } else {
+      sql_debug("a tuple is filtered: %s", tuple_.to_string().c_str());
       rc = RC::RECORD_EOF;
     }
   }

src/observer/sql/optimizer/comparison_simplification_rule.h

@@ -19,6 +19,12 @@ See the Mulan PSL v2 for more details. */
 
 class LogicalOperator;
 
+/**
+ * @brief 简单比较的重写规则
+ * @ingroup Rewriter
+ * @details 如果有简单的比较运算，比如比较的两边都是常量，那我们就可以在运行执行计划之前就知道结果，
+ * 进而直接将表达式改成结果，这样就可以减少运行时的计算量。
+ */
 class ComparisonSimplificationRule : public ExpressionRewriteRule 
 {
 public:

src/observer/sql/optimizer/conjunction_simplification_rule.h

@@ -19,8 +19,9 @@ See the Mulan PSL v2 for more details. */
 class LogicalOperator;
 
 /**
- * 简化多个表达式联结的运算
- * 比如只有一个表达式，或者表达式可以直接出来
+ * @brief 简化多个表达式联结的运算
+ * @ingroup Rewriter
+ * @details 比如只有一个表达式，或者表达式可以直接出来
  */
 class ConjunctionSimplificationRule : public ExpressionRewriteRule 
 {

src/observer/sql/optimizer/physical_plan_generator.h

@@ -28,7 +28,14 @@ class DeleteLogicalOperator;
 class ExplainLogicalOperator;
 class JoinLogicalOperator;
 
-class PhysicalPlanGenerator {
+/**
+ * @brief 物理计划生成器
+ * @ingroup PhysicalOperator
+ * @details 根据逻辑计划生成物理计划。
+ * 不会做任何优化，完全根据本意生成物理计划。
+ */
+class PhysicalPlanGenerator 
+{
 public:
   PhysicalPlanGenerator() = default;
   virtual ~PhysicalPlanGenerator() = default;

src/observer/sql/optimizer/predicate_pushdown_rewriter.h

@@ -18,8 +18,9 @@ See the Mulan PSL v2 for more details. */
 #include "sql/optimizer/rewrite_rule.h"
 
 /**
- * 将一些谓词表达式下推到表数据扫描中
- * 这样可以提前过滤一些数据
+ * @brief 将一些谓词表达式下推到表数据扫描中
+ * @ingroup Rewriter
+ * @details 这样可以提前过滤一些数据
  */
 class PredicatePushdownRewriter : public RewriteRule 
 {

src/observer/sql/optimizer/predicate_rewrite.h

@@ -16,6 +16,11 @@ See the Mulan PSL v2 for more details. */
 
 #include "sql/optimizer/rewrite_rule.h"
 
+/**
+ * @brief 谓词重写规则
+ * @ingroup Rewriter
+ * @details 有些谓词可以在真正运行之前就知道结果，那么就可以提前运算出来，比如1=1,1=0。
+ */
 class PredicateRewriteRule : public RewriteRule 
 {
 public:

src/observer/sql/optimizer/rewrite_rule.h

@@ -21,6 +21,10 @@ See the Mulan PSL v2 for more details. */
 class LogicalOperator;
 class Expression;
 
+/**
+ * @brief 逻辑计划的重写规则
+ * @ingroup Rewriter
+ */
 class RewriteRule 
 {
 public:
@@ -29,6 +33,10 @@ public:
   virtual RC rewrite(std::unique_ptr<LogicalOperator> &oper, bool &change_made) = 0;
 };
 
+/**
+ * @brief 表达式的重写规则
+ * @ingroup Rewriter
+ */
 class ExpressionRewriteRule 
 {
 public:

src/observer/sql/optimizer/rewriter.h

@@ -20,12 +20,30 @@ See the Mulan PSL v2 for more details. */
 
 class LogicalOperator;
 
+/**
+ * @defgroup Rewriter 
+ * @brief 根据规则对逻辑计划进行重写
+ */
+
+/**
+ * @brief 根据一些规则对逻辑计划进行重写
+ * @ingroup Rewriter
+ * @details 当前仅实现了一两个非常简单的规则。
+ * 重写包括对逻辑计划和计划中包含的表达式。
+ */
 class Rewriter 
 {
 public:
   Rewriter();
   virtual ~Rewriter() = default;
 
+  /**
+   * @brief 对逻辑计划进行重写
+   * @details 如果重写发生，change_made为true，否则为false。
+   * 通常情况下如果改写发生改变，就会继续重写，直到没有改变为止。
+   * @param oper 逻辑计划
+   * @param change_made 当前是否有重写发生
+   */
   RC rewrite(std::unique_ptr<LogicalOperator> &oper, bool &change_made);
 
 private:

src/observer/sql/parser/parse_defs.h

@@ -187,6 +187,12 @@ struct LoadData
   std::string file_name;
 };
 
+struct SetVariable
+{
+  std::string name;
+  Value value;
+};
+
 class Command;
 
 /**
@@ -229,7 +235,7 @@ enum SqlCommandFlag
   SCF_SYNC,
   SCF_SHOW_TABLES,
   SCF_DESC_TABLE,
-  SCF_BEGIN,        /// 事务开始语句，可以在这里扩展只读事务
+  SCF_BEGIN,        ///< 事务开始语句，可以在这里扩展只读事务
   SCF_COMMIT,
   SCF_CLOG_SYNC,
   SCF_ROLLBACK,
@@ -237,6 +243,7 @@ enum SqlCommandFlag
   SCF_HELP,
   SCF_EXIT,
   SCF_EXPLAIN,
+  SCF_SET_VARIABLE, ///< 设置变量
 };
 /**
  * @brief 表示一个SQL语句
@@ -258,6 +265,7 @@ public:
   DescTable desc_table;
   LoadData load_data;
   Explain explain;
+  SetVariable set_variable;
 
 public:
   Command();
@@ -278,5 +286,5 @@ public:
   }
 
 private:
-  std::vector<std::unique_ptr<Command>> sql_commands_;  /// 这里记录SQL命令。虽然看起来支持多个，但是当前仅处理一个
+  std::vector<std::unique_ptr<Command>> sql_commands_;  ///< 这里记录SQL命令。虽然看起来支持多个，但是当前仅处理一个
 };

src/observer/sql/parser/value.cpp

@@ -145,8 +145,9 @@ const char *Value::data() const
   }
 }
 
-void Value::to_string(std::ostream &os) const
+std::string Value::to_string() const
 {
+  std::stringstream os;
   switch (attr_type_) {
     case INTS: {
       os << num_value_.int_value_;
@@ -164,6 +165,7 @@ void Value::to_string(std::ostream &os) const
       LOG_WARN("unsupported attr type: %d", attr_type_);
     } break;
   }
+  return os.str();
 }
 
 int Value::compare(const Value &other) const
@@ -258,9 +260,7 @@ float Value::get_float() const
 
 std::string Value::get_string() const
 {
-  std::stringstream ss;
-  to_string(ss);
-  return ss.str();
+  return this->to_string();
 }
 
 bool Value::get_boolean() const

src/observer/sql/parser/value.h

@@ -14,6 +14,8 @@ See the Mulan PSL v2 for more details. */
 
 #pragma once
 
+#include <string>
+
 /**
  * @brief 属性的类型
  * 
@@ -67,7 +69,7 @@ public:
   void set_string(const char *s, int len = 0);
   void set_value(const Value &value);
 
-  void to_string(std::ostream &os) const;
+  std::string to_string() const;
 
   int compare(const Value &other) const;
 

src/observer/sql/parser/yacc_sql.cpp

@@ -208,7 +208,8 @@ enum yysymbol_kind_t
   YYSYMBOL_comp_op = 84,                   /* comp_op  */
   YYSYMBOL_load_data = 85,                 /* load_data  */
   YYSYMBOL_explain = 86,                   /* explain  */
-  YYSYMBOL_opt_semicolon = 87              /* opt_semicolon  */
+  YYSYMBOL_set_variable = 87,              /* set_variable  */
+  YYSYMBOL_opt_semicolon = 88              /* opt_semicolon  */
 };
 typedef enum yysymbol_kind_t yysymbol_kind_t;
 
@@ -519,18 +520,18 @@ union yyalloc
 #endif /* !YYCOPY_NEEDED */
 
 /* YYFINAL -- State number of the termination state.  */
-#define YYFINAL  52
+#define YYFINAL  55
 /* YYLAST -- Last index in YYTABLE.  */
-#define YYLAST   112
+#define YYLAST   127
 
 /* YYNTOKENS -- Number of terminals.  */
 #define YYNTOKENS  52
 /* YYNNTS -- Number of nonterminals.  */
-#define YYNNTS  36
+#define YYNNTS  37
 /* YYNRULES -- Number of rules.  */
-#define YYNRULES  76
+#define YYNRULES  78
 /* YYNSTATES -- Number of states.  */
-#define YYNSTATES  138
+#define YYNSTATES  143
 
 /* YYMAXUTOK -- Last valid token kind.  */
 #define YYMAXUTOK   306
@@ -584,14 +585,14 @@ static const yytype_int8 yytranslate[] =
   /* YYRLINE[YYN] -- Source line where rule number YYN was defined.  */
 static const yytype_int16 yyrline[] =
 {
-       0,   142,   142,   150,   151,   152,   153,   154,   155,   156,
-     157,   158,   159,   160,   161,   162,   163,   164,   165,   166,
-     167,   171,   177,   182,   188,   194,   200,   206,   213,   219,
-     227,   241,   251,   270,   273,   286,   294,   304,   307,   308,
-     309,   312,   328,   331,   342,   345,   348,   356,   368,   383,
-     406,   413,   425,   430,   441,   444,   458,   461,   474,   477,
-     483,   486,   491,   498,   510,   522,   534,   549,   550,   551,
-     552,   553,   554,   558,   568,   575,   576
+       0,   143,   143,   151,   152,   153,   154,   155,   156,   157,
+     158,   159,   160,   161,   162,   163,   164,   165,   166,   167,
+     168,   169,   173,   179,   184,   190,   196,   202,   208,   215,
+     221,   229,   243,   253,   272,   275,   288,   296,   306,   309,
+     310,   311,   314,   330,   333,   344,   347,   350,   358,   370,
+     385,   408,   415,   427,   432,   443,   446,   460,   463,   476,
+     479,   485,   488,   493,   500,   512,   524,   536,   551,   552,
+     553,   554,   555,   556,   560,   570,   578,   588,   589
 };
 #endif
 
@@ -620,7 +621,7 @@ static const char *const yytname[] =
   "type", "insert", "value_list", "value", "delete", "update", "select",
   "select_attr", "rel_attr", "attr_list", "rel_list", "where",
   "condition_list", "condition", "comp_op", "load_data", "explain",
-  "opt_semicolon", YY_NULLPTR
+  "set_variable", "opt_semicolon", YY_NULLPTR
 };
 
 static const char *
@@ -644,7 +645,7 @@ static const yytype_int16 yytoknum[] =
 };
 #endif
 
-#define YYPACT_NINF (-85)
+#define YYPACT_NINF (-88)
 
 #define yypact_value_is_default(Yyn) \
   ((Yyn) == YYPACT_NINF)
@@ -658,20 +659,21 @@ static const yytype_int16 yytoknum[] =
      STATE-NUM.  */
 static const yytype_int8 yypact[] =
 {
-      10,    26,    46,    -6,   -37,     4,   -85,   -11,   -12,   -21,
-     -85,   -85,   -85,   -85,   -85,     7,    10,    47,    43,   -85,
-     -85,   -85,   -85,   -85,   -85,   -85,   -85,   -85,   -85,   -85,
-     -85,   -85,   -85,   -85,   -85,   -85,   -85,     6,     8,     9,
-      12,    30,   -85,    31,    42,   -85,   -85,    15,    16,    32,
-      29,   -85,   -85,   -85,   -85,    48,    33,   -85,    34,    22,
-      23,    24,   -85,    44,    41,    28,    25,    35,    36,    37,
-     -85,    58,    42,    61,    -7,   -85,    39,    51,    27,    62,
-      65,   -85,    38,    41,   -85,   -33,   -85,   -85,   -85,   -36,
-     -36,   -85,    54,   -33,    81,   -85,   -85,   -85,    72,    35,
-      73,    45,    58,   -85,    71,   -85,   -85,   -85,   -85,   -85,
-     -85,    -7,    -7,    -7,    41,    49,    50,    62,   -85,    74,
-     -85,   -33,    76,   -85,   -85,   -85,   -85,   -85,   -85,   -85,
-     -85,    77,   -85,   -85,    71,   -85,   -85,   -85
+      -2,    14,    29,   -21,   -42,    20,   -88,   -22,    -9,   -19,
+     -88,   -88,   -88,   -88,   -88,   -13,     8,    -2,    45,    43,
+     -88,   -88,   -88,   -88,   -88,   -88,   -88,   -88,   -88,   -88,
+     -88,   -88,   -88,   -88,   -88,   -88,   -88,   -88,   -88,     0,
+       6,    13,    15,    30,   -88,    33,    46,   -88,   -88,    18,
+      19,    34,    31,    32,   -88,   -88,   -88,   -88,    52,    37,
+     -88,    38,    26,    27,    28,   -88,    47,    48,    35,    10,
+      36,    39,    40,    41,   -88,    59,    46,    62,     5,   -88,
+      42,   -88,   -88,   -88,   -88,    55,    -8,    66,    64,   -88,
+      44,    48,   -88,    10,    -1,    -1,   -88,    57,    10,    84,
+     -88,   -88,   -88,    76,    39,    77,    49,    59,   -88,    75,
+     -88,   -88,   -88,   -88,   -88,   -88,     5,     5,     5,    48,
+      50,    53,    66,   -88,    78,   -88,    10,    82,   -88,   -88,
+     -88,   -88,   -88,   -88,   -88,   -88,    83,   -88,   -88,    75,
+     -88,   -88,   -88
 };
 
   /* YYDEFACT[STATE-NUM] -- Default reduction number in state STATE-NUM.
@@ -679,38 +681,39 @@ static const yytype_int8 yypact[] =
      means the default is an error.  */
 static const yytype_int8 yydefact[] =
 {
-       0,     0,     0,     0,     0,     0,    23,     0,     0,     0,
-      24,    25,    26,    22,    21,     0,     0,     0,    75,    20,
-      19,    13,    14,    15,    16,     8,     9,    10,    11,    12,
-       7,     4,     6,     5,     3,    17,    18,     0,     0,     0,
-       0,    52,    50,     0,    54,    29,    28,     0,     0,     0,
-       0,    74,     1,    76,     2,     0,     0,    27,     0,     0,
-       0,     0,    51,     0,    58,     0,     0,     0,     0,     0,
-      53,    56,    54,     0,    60,    47,     0,     0,     0,    33,
-       0,    31,     0,    58,    55,     0,    44,    45,    46,     0,
-       0,    59,    61,     0,     0,    38,    39,    40,    36,     0,
-       0,     0,    56,    49,    42,    67,    68,    69,    70,    71,
-      72,     0,     0,    60,    58,     0,     0,    33,    32,     0,
-      57,     0,     0,    64,    66,    63,    65,    62,    48,    73,
-      37,     0,    34,    30,    42,    41,    35,    43
+       0,     0,     0,     0,     0,     0,    24,     0,     0,     0,
+      25,    26,    27,    23,    22,     0,     0,     0,     0,    77,
+      21,    20,    13,    14,    15,    16,     8,     9,    10,    11,
+      12,     7,     4,     6,     5,     3,    17,    18,    19,     0,
+       0,     0,     0,    53,    51,     0,    55,    30,    29,     0,
+       0,     0,     0,     0,    75,     1,    78,     2,     0,     0,
+      28,     0,     0,     0,     0,    52,     0,    59,     0,     0,
+       0,     0,     0,     0,    54,    57,    55,     0,    61,    48,
+       0,    45,    46,    47,    76,     0,     0,    34,     0,    32,
+       0,    59,    56,     0,     0,     0,    60,    62,     0,     0,
+      39,    40,    41,    37,     0,     0,     0,    57,    50,    43,
+      68,    69,    70,    71,    72,    73,     0,     0,    61,    59,
+       0,     0,    34,    33,     0,    58,     0,     0,    65,    67,
+      64,    66,    63,    49,    74,    38,     0,    35,    31,    43,
+      42,    36,    44
 };
 
   /* YYPGOTO[NTERM-NUM].  */
 static const yytype_int8 yypgoto[] =
 {
-     -85,   -85,    82,   -85,   -85,   -85,   -85,   -85,   -85,   -85,
-     -85,   -85,   -85,   -85,   -85,   -20,     0,   -85,   -85,   -85,
-     -34,   -84,   -85,   -85,   -85,   -85,    -3,    40,    -1,   -81,
-     -10,   -85,    14,   -85,   -85,   -85
+     -88,   -88,    85,   -88,   -88,   -88,   -88,   -88,   -88,   -88,
+     -88,   -88,   -88,   -88,   -88,   -18,     1,   -88,   -88,   -88,
+     -38,   -68,   -88,   -88,   -88,   -88,    -3,    51,    -4,   -87,
+     -12,   -88,    12,   -88,   -88,   -88,   -88
 };
 
   /* YYDEFGOTO[NTERM-NUM].  */
 static const yytype_int16 yydefgoto[] =
 {
-      -1,    17,    18,    19,    20,    21,    22,    23,    24,    25,
-      26,    27,    28,    29,    30,   100,    79,   131,    98,    31,
-     122,    89,    32,    33,    34,    43,    90,    62,    83,    75,
-      91,    92,   111,    35,    36,    54
+      -1,    18,    19,    20,    21,    22,    23,    24,    25,    26,
+      27,    28,    29,    30,    31,   105,    87,   136,   103,    32,
+     127,    94,    33,    34,    35,    45,    95,    65,    91,    79,
+      96,    97,   116,    36,    37,    38,    57
 };
 
   /* YYTABLE[YYPACT[STATE-NUM]] -- What to do in state STATE-NUM.  If
@@ -718,34 +721,36 @@ static const yytype_int16 yydefgoto[] =
      number is the opposite.  If YYTABLE_NINF, syntax error.  */
 static const yytype_uint8 yytable[] =
 {
-      44,   104,   103,   105,   106,   107,   108,   109,   110,   114,
-      45,    46,    86,    87,     1,     2,    88,    47,    48,     3,
-       4,     5,     6,     7,     8,     9,    49,   123,   125,    10,
-      11,    12,    37,   128,    38,    13,    14,   134,    86,    87,
-      41,    41,    88,    50,    42,    15,    53,    52,    16,    95,
-      96,    97,    39,    55,    40,    56,    57,    59,    72,    58,
-      61,    60,    63,    64,    67,    65,    66,    68,    69,    70,
-      71,    41,    74,    73,    77,    76,    82,    85,    93,    94,
-      99,   101,    78,    80,    81,   102,   113,   115,   116,   121,
-     118,   133,   119,   135,   136,   130,   129,   132,    51,   117,
-     137,   120,     0,   127,   112,     0,     0,     0,   124,   126,
-       0,     0,    84
+      46,    84,     1,     2,   108,    47,    49,     3,     4,     5,
+       6,     7,     8,     9,   100,   101,   102,    10,    11,    12,
+      39,    50,    40,    13,    14,   109,    43,    48,    51,    44,
+     119,    15,   133,    16,    52,    41,    17,    42,   110,   111,
+     112,   113,   114,   115,    53,    55,    56,    58,   128,   130,
+      81,    82,    43,    59,    83,    81,    82,    62,   139,    83,
+      60,    76,    61,    63,    64,    66,    67,    68,    71,    70,
+      69,    72,    73,    74,    75,    43,    77,    90,    93,    78,
+     106,    98,    80,    99,   104,    85,    86,    88,    89,   118,
+     120,   107,   121,   126,   123,   138,   124,   134,   135,   140,
+     141,   142,    54,   125,   137,   122,   132,   117,     0,     0,
+       0,     0,     0,   129,   131,     0,     0,     0,     0,     0,
+       0,     0,     0,     0,     0,     0,     0,    92
 };
 
 static const yytype_int16 yycheck[] =
 {
-       3,    85,    83,    39,    40,    41,    42,    43,    44,    93,
-      47,     7,    45,    46,     4,     5,    49,    28,    30,     9,
-      10,    11,    12,    13,    14,    15,    47,   111,   112,    19,
-      20,    21,     6,   114,     8,    25,    26,   121,    45,    46,
-      47,    47,    49,    36,    50,    35,     3,     0,    38,    22,
-      23,    24,     6,    47,     8,    47,    47,    27,    61,    47,
-      18,    30,    47,    47,    16,    33,    37,    34,    34,    47,
-      47,    47,    31,    29,    49,    47,    18,    16,    39,    28,
-      18,    16,    47,    47,    47,    47,    32,     6,    16,    18,
-      17,    17,    47,    17,    17,    45,    47,   117,    16,    99,
-     134,   102,    -1,   113,    90,    -1,    -1,    -1,   111,   112,
-      -1,    -1,    72
+       3,    69,     4,     5,    91,    47,    28,     9,    10,    11,
+      12,    13,    14,    15,    22,    23,    24,    19,    20,    21,
+       6,    30,     8,    25,    26,    93,    47,     7,    47,    50,
+      98,    33,   119,    35,    47,     6,    38,     8,    39,    40,
+      41,    42,    43,    44,    36,     0,     3,    47,   116,   117,
+      45,    46,    47,    47,    49,    45,    46,    27,   126,    49,
+      47,    64,    47,    30,    18,    47,    47,    33,    16,    37,
+      39,    34,    34,    47,    47,    47,    29,    18,    16,    31,
+      16,    39,    47,    28,    18,    49,    47,    47,    47,    32,
+       6,    47,    16,    18,    17,    17,    47,    47,    45,    17,
+      17,   139,    17,   107,   122,   104,   118,    95,    -1,    -1,
+      -1,    -1,    -1,   116,   117,    -1,    -1,    -1,    -1,    -1,
+      -1,    -1,    -1,    -1,    -1,    -1,    -1,    76
 };
 
   /* YYSTOS[STATE-NUM] -- The (internal number of the) accessing
@@ -753,19 +758,20 @@ static const yytype_int16 yycheck[] =
 static const yytype_int8 yystos[] =
 {
        0,     4,     5,     9,    10,    11,    12,    13,    14,    15,
-      19,    20,    21,    25,    26,    35,    38,    53,    54,    55,
-      56,    57,    58,    59,    60,    61,    62,    63,    64,    65,
-      66,    71,    74,    75,    76,    85,    86,     6,     8,     6,
-       8,    47,    50,    77,    78,    47,     7,    28,    30,    47,
-      36,    54,     0,     3,    87,    47,    47,    47,    47,    27,
-      30,    18,    79,    47,    47,    33,    37,    16,    34,    34,
-      47,    47,    78,    29,    31,    81,    47,    49,    47,    68,
-      47,    47,    18,    80,    79,    16,    45,    46,    49,    73,
-      78,    82,    83,    39,    28,    22,    23,    24,    70,    18,
-      67,    16,    47,    81,    73,    39,    40,    41,    42,    43,
-      44,    84,    84,    32,    73,     6,    16,    68,    17,    47,
-      80,    18,    72,    73,    78,    73,    78,    82,    81,    47,
-      45,    69,    67,    17,    73,    17,    17,    72
+      19,    20,    21,    25,    26,    33,    35,    38,    53,    54,
+      55,    56,    57,    58,    59,    60,    61,    62,    63,    64,
+      65,    66,    71,    74,    75,    76,    85,    86,    87,     6,
+       8,     6,     8,    47,    50,    77,    78,    47,     7,    28,
+      30,    47,    47,    36,    54,     0,     3,    88,    47,    47,
+      47,    47,    27,    30,    18,    79,    47,    47,    33,    39,
+      37,    16,    34,    34,    47,    47,    78,    29,    31,    81,
+      47,    45,    46,    49,    73,    49,    47,    68,    47,    47,
+      18,    80,    79,    16,    73,    78,    82,    83,    39,    28,
+      22,    23,    24,    70,    18,    67,    16,    47,    81,    73,
+      39,    40,    41,    42,    43,    44,    84,    84,    32,    73,
+       6,    16,    68,    17,    47,    80,    18,    72,    73,    78,
+      73,    78,    82,    81,    47,    45,    69,    67,    17,    73,
+      17,    17,    72
 };
 
   /* YYR1[YYN] -- Symbol number of symbol that rule YYN derives.  */
@@ -773,12 +779,12 @@ static const yytype_int8 yyr1[] =
 {
        0,    52,    53,    54,    54,    54,    54,    54,    54,    54,
       54,    54,    54,    54,    54,    54,    54,    54,    54,    54,
-      54,    55,    56,    57,    58,    59,    60,    61,    62,    63,
-      64,    65,    66,    67,    67,    68,    68,    69,    70,    70,
-      70,    71,    72,    72,    73,    73,    73,    74,    75,    76,
-      77,    77,    78,    78,    79,    79,    80,    80,    81,    81,
-      82,    82,    82,    83,    83,    83,    83,    84,    84,    84,
-      84,    84,    84,    85,    86,    87,    87
+      54,    54,    55,    56,    57,    58,    59,    60,    61,    62,
+      63,    64,    65,    66,    67,    67,    68,    68,    69,    70,
+      70,    70,    71,    72,    72,    73,    73,    73,    74,    75,
+      76,    77,    77,    78,    78,    79,    79,    80,    80,    81,
+      81,    82,    82,    82,    83,    83,    83,    83,    84,    84,
+      84,    84,    84,    84,    85,    86,    87,    88,    88
 };
 
   /* YYR2[YYN] -- Number of symbols on the right hand side of rule YYN.  */
@@ -786,12 +792,12 @@ static const yytype_int8 yyr2[] =
 {
        0,     2,     2,     1,     1,     1,     1,     1,     1,     1,
        1,     1,     1,     1,     1,     1,     1,     1,     1,     1,
-       1,     1,     1,     1,     1,     1,     1,     3,     2,     2,
-       8,     5,     7,     0,     3,     5,     2,     1,     1,     1,
-       1,     8,     0,     3,     1,     1,     1,     4,     7,     6,
-       1,     2,     1,     3,     0,     3,     0,     3,     0,     2,
-       0,     1,     3,     3,     3,     3,     3,     1,     1,     1,
-       1,     1,     1,     7,     2,     0,     1
+       1,     1,     1,     1,     1,     1,     1,     1,     3,     2,
+       2,     8,     5,     7,     0,     3,     5,     2,     1,     1,
+       1,     1,     8,     0,     3,     1,     1,     1,     4,     7,
+       6,     1,     2,     1,     3,     0,     3,     0,     3,     0,
+       2,     0,     1,     3,     3,     3,     3,     3,     1,     1,
+       1,     1,     1,     1,     7,     2,     4,     0,     1
 };
 
 
@@ -1637,93 +1643,93 @@ yyreduce:
   switch (yyn)
     {
   case 2: /* commands: command_wrapper opt_semicolon  */
-#line 143 "yacc_sql.y"
+#line 144 "yacc_sql.y"
   {
     std::unique_ptr<Command> sql_command = std::unique_ptr<Command>((yyvsp[-1].command));
     sql_result->add_command(std::move(sql_command));
   }
-#line 1646 "yacc_sql.cpp"
+#line 1652 "yacc_sql.cpp"
     break;
 
-  case 21: /* exit: EXIT  */
-#line 171 "yacc_sql.y"
+  case 22: /* exit: EXIT  */
+#line 173 "yacc_sql.y"
          {
       (void)yynerrs;  // 这么写为了消除yynerrs未使用的告警。如果你有更好的方法欢迎提PR
       (yyval.command) = new Command(SCF_EXIT);
     }
-#line 1655 "yacc_sql.cpp"
+#line 1661 "yacc_sql.cpp"
     break;
 
-  case 22: /* help: HELP  */
-#line 177 "yacc_sql.y"
+  case 23: /* help: HELP  */
+#line 179 "yacc_sql.y"
          {
       (yyval.command) = new Command(SCF_HELP);
     }
-#line 1663 "yacc_sql.cpp"
+#line 1669 "yacc_sql.cpp"
     break;
 
-  case 23: /* sync: SYNC  */
-#line 182 "yacc_sql.y"
+  case 24: /* sync: SYNC  */
+#line 184 "yacc_sql.y"
          {
       (yyval.command) = new Command(SCF_SYNC);
     }
-#line 1671 "yacc_sql.cpp"
+#line 1677 "yacc_sql.cpp"
     break;
 
-  case 24: /* begin: TRX_BEGIN  */
-#line 188 "yacc_sql.y"
+  case 25: /* begin: TRX_BEGIN  */
+#line 190 "yacc_sql.y"
                {
       (yyval.command) = new Command(SCF_BEGIN);
     }
-#line 1679 "yacc_sql.cpp"
+#line 1685 "yacc_sql.cpp"
     break;
 
-  case 25: /* commit: TRX_COMMIT  */
-#line 194 "yacc_sql.y"
+  case 26: /* commit: TRX_COMMIT  */
+#line 196 "yacc_sql.y"
                {
       (yyval.command) = new Command(SCF_COMMIT);
     }
-#line 1687 "yacc_sql.cpp"
+#line 1693 "yacc_sql.cpp"
     break;
 
-  case 26: /* rollback: TRX_ROLLBACK  */
-#line 200 "yacc_sql.y"
+  case 27: /* rollback: TRX_ROLLBACK  */
+#line 202 "yacc_sql.y"
                   {
       (yyval.command) = new Command(SCF_ROLLBACK);
     }
-#line 1695 "yacc_sql.cpp"
+#line 1701 "yacc_sql.cpp"
     break;
 
-  case 27: /* drop_table: DROP TABLE ID  */
-#line 206 "yacc_sql.y"
+  case 28: /* drop_table: DROP TABLE ID  */
+#line 208 "yacc_sql.y"
                   {
       (yyval.command) = new Command(SCF_DROP_TABLE);
       (yyval.command)->drop_table.relation_name = (yyvsp[0].string);
       free((yyvsp[0].string));
     }
-#line 1705 "yacc_sql.cpp"
+#line 1711 "yacc_sql.cpp"
     break;
 
-  case 28: /* show_tables: SHOW TABLES  */
-#line 213 "yacc_sql.y"
+  case 29: /* show_tables: SHOW TABLES  */
+#line 215 "yacc_sql.y"
                 {
       (yyval.command) = new Command(SCF_SHOW_TABLES);
     }
-#line 1713 "yacc_sql.cpp"
+#line 1719 "yacc_sql.cpp"
     break;
 
-  case 29: /* desc_table: DESC ID  */
-#line 219 "yacc_sql.y"
+  case 30: /* desc_table: DESC ID  */
+#line 221 "yacc_sql.y"
              {
       (yyval.command) = new Command(SCF_DESC_TABLE);
       (yyval.command)->desc_table.relation_name = (yyvsp[0].string);
       free((yyvsp[0].string));
     }
-#line 1723 "yacc_sql.cpp"
+#line 1729 "yacc_sql.cpp"
     break;
 
-  case 30: /* create_index: CREATE INDEX ID ON ID LBRACE ID RBRACE  */
-#line 228 "yacc_sql.y"
+  case 31: /* create_index: CREATE INDEX ID ON ID LBRACE ID RBRACE  */
+#line 230 "yacc_sql.y"
     {
       (yyval.command) = new Command(SCF_CREATE_INDEX);
       CreateIndex &create_index = (yyval.command)->create_index;
@@ -1734,11 +1740,11 @@ yyreduce:
       free((yyvsp[-3].string));
       free((yyvsp[-1].string));
     }
-#line 1738 "yacc_sql.cpp"
+#line 1744 "yacc_sql.cpp"
     break;
 
-  case 31: /* drop_index: DROP INDEX ID ON ID  */
-#line 242 "yacc_sql.y"
+  case 32: /* drop_index: DROP INDEX ID ON ID  */
+#line 244 "yacc_sql.y"
     {
       (yyval.command) = new Command(SCF_DROP_INDEX);
       (yyval.command)->drop_index.index_name = (yyvsp[-2].string);
@@ -1746,11 +1752,11 @@ yyreduce:
       free((yyvsp[-2].string));
       free((yyvsp[0].string));
     }
-#line 1750 "yacc_sql.cpp"
+#line 1756 "yacc_sql.cpp"
     break;
 
-  case 32: /* create_table: CREATE TABLE ID LBRACE attr_def attr_def_list RBRACE  */
-#line 252 "yacc_sql.y"
+  case 33: /* create_table: CREATE TABLE ID LBRACE attr_def attr_def_list RBRACE  */
+#line 254 "yacc_sql.y"
     {
       (yyval.command) = new Command(SCF_CREATE_TABLE);
       CreateTable &create_table = (yyval.command)->create_table;
@@ -1766,19 +1772,19 @@ yyreduce:
       std::reverse(create_table.attr_infos.begin(), create_table.attr_infos.end());
       delete (yyvsp[-2].attr_info);
     }
-#line 1770 "yacc_sql.cpp"
+#line 1776 "yacc_sql.cpp"
     break;
 
-  case 33: /* attr_def_list: %empty  */
-#line 270 "yacc_sql.y"
+  case 34: /* attr_def_list: %empty  */
+#line 272 "yacc_sql.y"
     {
       (yyval.attr_infos) = nullptr;
     }
-#line 1778 "yacc_sql.cpp"
+#line 1784 "yacc_sql.cpp"
     break;
 
-  case 34: /* attr_def_list: COMMA attr_def attr_def_list  */
-#line 274 "yacc_sql.y"
+  case 35: /* attr_def_list: COMMA attr_def attr_def_list  */
+#line 276 "yacc_sql.y"
     {
       if ((yyvsp[0].attr_infos) != nullptr) {
         (yyval.attr_infos) = (yyvsp[0].attr_infos);
@@ -1788,11 +1794,11 @@ yyreduce:
       (yyval.attr_infos)->emplace_back(*(yyvsp[-1].attr_info));
       delete (yyvsp[-1].attr_info);
     }
-#line 1792 "yacc_sql.cpp"
+#line 1798 "yacc_sql.cpp"
     break;
 
-  case 35: /* attr_def: ID type LBRACE number RBRACE  */
-#line 287 "yacc_sql.y"
+  case 36: /* attr_def: ID type LBRACE number RBRACE  */
+#line 289 "yacc_sql.y"
     {
       (yyval.attr_info) = new AttrInfo;
       (yyval.attr_info)->type = (AttrType)(yyvsp[-3].number);
@@ -1800,11 +1806,11 @@ yyreduce:
       (yyval.attr_info)->length = (yyvsp[-1].number);
       free((yyvsp[-4].string));
     }
-#line 1804 "yacc_sql.cpp"
+#line 1810 "yacc_sql.cpp"
     break;
 
-  case 36: /* attr_def: ID type  */
-#line 295 "yacc_sql.y"
+  case 37: /* attr_def: ID type  */
+#line 297 "yacc_sql.y"
     {
       (yyval.attr_info) = new AttrInfo;
       (yyval.attr_info)->type = (AttrType)(yyvsp[0].number);
@@ -1812,35 +1818,35 @@ yyreduce:
       (yyval.attr_info)->length = 4;
       free((yyvsp[-1].string));
     }
-#line 1816 "yacc_sql.cpp"
+#line 1822 "yacc_sql.cpp"
     break;
 
-  case 37: /* number: NUMBER  */
-#line 304 "yacc_sql.y"
+  case 38: /* number: NUMBER  */
+#line 306 "yacc_sql.y"
            {(yyval.number) = (yyvsp[0].number);}
-#line 1822 "yacc_sql.cpp"
+#line 1828 "yacc_sql.cpp"
     break;
 
-  case 38: /* type: INT_T  */
-#line 307 "yacc_sql.y"
+  case 39: /* type: INT_T  */
+#line 309 "yacc_sql.y"
                { (yyval.number)=INTS; }
-#line 1828 "yacc_sql.cpp"
+#line 1834 "yacc_sql.cpp"
     break;
 
-  case 39: /* type: STRING_T  */
-#line 308 "yacc_sql.y"
+  case 40: /* type: STRING_T  */
+#line 310 "yacc_sql.y"
                { (yyval.number)=CHARS; }
-#line 1834 "yacc_sql.cpp"
+#line 1840 "yacc_sql.cpp"
     break;
 
-  case 40: /* type: FLOAT_T  */
-#line 309 "yacc_sql.y"
+  case 41: /* type: FLOAT_T  */
+#line 311 "yacc_sql.y"
                { (yyval.number)=FLOATS; }
-#line 1840 "yacc_sql.cpp"
+#line 1846 "yacc_sql.cpp"
     break;
 
-  case 41: /* insert: INSERT INTO ID VALUES LBRACE value value_list RBRACE  */
-#line 313 "yacc_sql.y"
+  case 42: /* insert: INSERT INTO ID VALUES LBRACE value value_list RBRACE  */
+#line 315 "yacc_sql.y"
     {
       (yyval.command) = new Command(SCF_INSERT);
       (yyval.command)->insertion.relation_name = (yyvsp[-5].string);
@@ -1852,19 +1858,19 @@ yyreduce:
       delete (yyvsp[-2].value);
       free((yyvsp[-5].string));
     }
-#line 1856 "yacc_sql.cpp"
+#line 1862 "yacc_sql.cpp"
     break;
 
-  case 42: /* value_list: %empty  */
-#line 328 "yacc_sql.y"
+  case 43: /* value_list: %empty  */
+#line 330 "yacc_sql.y"
     {
       (yyval.value_list) = nullptr;
     }
-#line 1864 "yacc_sql.cpp"
+#line 1870 "yacc_sql.cpp"
     break;
 
-  case 43: /* value_list: COMMA value value_list  */
-#line 331 "yacc_sql.y"
+  case 44: /* value_list: COMMA value value_list  */
+#line 333 "yacc_sql.y"
                               { 
       if ((yyvsp[0].value_list) != nullptr) {
         (yyval.value_list) = (yyvsp[0].value_list);
@@ -1874,37 +1880,37 @@ yyreduce:
       (yyval.value_list)->emplace_back(*(yyvsp[-1].value));
       delete (yyvsp[-1].value);
     }
-#line 1878 "yacc_sql.cpp"
+#line 1884 "yacc_sql.cpp"
     break;
 
-  case 44: /* value: NUMBER  */
-#line 342 "yacc_sql.y"
+  case 45: /* value: NUMBER  */
+#line 344 "yacc_sql.y"
            {
       (yyval.value) = new Value((int)(yyvsp[0].number));
     }
-#line 1886 "yacc_sql.cpp"
+#line 1892 "yacc_sql.cpp"
     break;
 
-  case 45: /* value: FLOAT  */
-#line 345 "yacc_sql.y"
+  case 46: /* value: FLOAT  */
+#line 347 "yacc_sql.y"
            {
       (yyval.value) = new Value((float)(yyvsp[0].floats));
     }
-#line 1894 "yacc_sql.cpp"
+#line 1900 "yacc_sql.cpp"
     break;
 
-  case 46: /* value: SSS  */
-#line 348 "yacc_sql.y"
+  case 47: /* value: SSS  */
+#line 350 "yacc_sql.y"
          {
       char *tmp = common::substr((yyvsp[0].string),1,strlen((yyvsp[0].string))-2);
       (yyval.value) = new Value(tmp);
       free(tmp);
     }
-#line 1904 "yacc_sql.cpp"
+#line 1910 "yacc_sql.cpp"
     break;
 
-  case 47: /* delete: DELETE FROM ID where  */
-#line 357 "yacc_sql.y"
+  case 48: /* delete: DELETE FROM ID where  */
+#line 359 "yacc_sql.y"
     {
       (yyval.command) = new Command(SCF_DELETE);
       (yyval.command)->deletion.relation_name = (yyvsp[-1].string);
@@ -1914,11 +1920,11 @@ yyreduce:
       }
       free((yyvsp[-1].string));
     }
-#line 1918 "yacc_sql.cpp"
+#line 1924 "yacc_sql.cpp"
     break;
 
-  case 48: /* update: UPDATE ID SET ID EQ value where  */
-#line 369 "yacc_sql.y"
+  case 49: /* update: UPDATE ID SET ID EQ value where  */
+#line 371 "yacc_sql.y"
     {
       (yyval.command) = new Command(SCF_UPDATE);
       (yyval.command)->update.relation_name = (yyvsp[-5].string);
@@ -1931,11 +1937,11 @@ yyreduce:
       free((yyvsp[-5].string));
       free((yyvsp[-3].string));
     }
-#line 1935 "yacc_sql.cpp"
+#line 1941 "yacc_sql.cpp"
     break;
 
-  case 49: /* select: SELECT select_attr FROM ID rel_list where  */
-#line 384 "yacc_sql.y"
+  case 50: /* select: SELECT select_attr FROM ID rel_list where  */
+#line 386 "yacc_sql.y"
     {
       (yyval.command) = new Command(SCF_SELECT);
       if ((yyvsp[-4].rel_attr_list) != nullptr) {
@@ -1955,11 +1961,11 @@ yyreduce:
       }
       free((yyvsp[-2].string));
     }
-#line 1959 "yacc_sql.cpp"
+#line 1965 "yacc_sql.cpp"
     break;
 
-  case 50: /* select_attr: STAR  */
-#line 406 "yacc_sql.y"
+  case 51: /* select_attr: STAR  */
+#line 408 "yacc_sql.y"
          {
       (yyval.rel_attr_list) = new std::vector<RelAttr>;
       RelAttr attr;
@@ -1967,11 +1973,11 @@ yyreduce:
       attr.attribute_name = "*";
       (yyval.rel_attr_list)->emplace_back(attr);
     }
-#line 1971 "yacc_sql.cpp"
+#line 1977 "yacc_sql.cpp"
     break;
 
-  case 51: /* select_attr: rel_attr attr_list  */
-#line 413 "yacc_sql.y"
+  case 52: /* select_attr: rel_attr attr_list  */
+#line 415 "yacc_sql.y"
                          {
       if ((yyvsp[0].rel_attr_list) != nullptr) {
         (yyval.rel_attr_list) = (yyvsp[0].rel_attr_list);
@@ -1981,21 +1987,21 @@ yyreduce:
       (yyval.rel_attr_list)->emplace_back(*(yyvsp[-1].rel_attr));
       delete (yyvsp[-1].rel_attr);
     }
-#line 1985 "yacc_sql.cpp"
+#line 1991 "yacc_sql.cpp"
     break;
 
-  case 52: /* rel_attr: ID  */
-#line 425 "yacc_sql.y"
+  case 53: /* rel_attr: ID  */
+#line 427 "yacc_sql.y"
        {
       (yyval.rel_attr) = new RelAttr;
       (yyval.rel_attr)->attribute_name = (yyvsp[0].string);
       free((yyvsp[0].string));
     }
-#line 1995 "yacc_sql.cpp"
+#line 2001 "yacc_sql.cpp"
     break;
 
-  case 53: /* rel_attr: ID DOT ID  */
-#line 430 "yacc_sql.y"
+  case 54: /* rel_attr: ID DOT ID  */
+#line 432 "yacc_sql.y"
                 {
       (yyval.rel_attr) = new RelAttr;
       (yyval.rel_attr)->relation_name = (yyvsp[-2].string);
@@ -2003,19 +2009,19 @@ yyreduce:
       free((yyvsp[-2].string));
       free((yyvsp[0].string));
     }
-#line 2007 "yacc_sql.cpp"
+#line 2013 "yacc_sql.cpp"
     break;
 
-  case 54: /* attr_list: %empty  */
-#line 441 "yacc_sql.y"
+  case 55: /* attr_list: %empty  */
+#line 443 "yacc_sql.y"
     {
       (yyval.rel_attr_list) = nullptr;
     }
-#line 2015 "yacc_sql.cpp"
+#line 2021 "yacc_sql.cpp"
     break;
 
-  case 55: /* attr_list: COMMA rel_attr attr_list  */
-#line 444 "yacc_sql.y"
+  case 56: /* attr_list: COMMA rel_attr attr_list  */
+#line 446 "yacc_sql.y"
                                {
       if ((yyvsp[0].rel_attr_list) != nullptr) {
         (yyval.rel_attr_list) = (yyvsp[0].rel_attr_list);
@@ -2026,19 +2032,19 @@ yyreduce:
       (yyval.rel_attr_list)->emplace_back(*(yyvsp[-1].rel_attr));
       delete (yyvsp[-1].rel_attr);
     }
-#line 2030 "yacc_sql.cpp"
+#line 2036 "yacc_sql.cpp"
     break;
 
-  case 56: /* rel_list: %empty  */
-#line 458 "yacc_sql.y"
+  case 57: /* rel_list: %empty  */
+#line 460 "yacc_sql.y"
     {
       (yyval.relation_list) = nullptr;
     }
-#line 2038 "yacc_sql.cpp"
+#line 2044 "yacc_sql.cpp"
     break;
 
-  case 57: /* rel_list: COMMA ID rel_list  */
-#line 461 "yacc_sql.y"
+  case 58: /* rel_list: COMMA ID rel_list  */
+#line 463 "yacc_sql.y"
                         {
       if ((yyvsp[0].relation_list) != nullptr) {
         (yyval.relation_list) = (yyvsp[0].relation_list);
@@ -2049,55 +2055,55 @@ yyreduce:
       (yyval.relation_list)->push_back((yyvsp[-1].string));
       free((yyvsp[-1].string));
     }
-#line 2053 "yacc_sql.cpp"
+#line 2059 "yacc_sql.cpp"
     break;
 
-  case 58: /* where: %empty  */
-#line 474 "yacc_sql.y"
+  case 59: /* where: %empty  */
+#line 476 "yacc_sql.y"
     {
       (yyval.condition_list) = nullptr;
     }
-#line 2061 "yacc_sql.cpp"
+#line 2067 "yacc_sql.cpp"
     break;
 
-  case 59: /* where: WHERE condition_list  */
-#line 477 "yacc_sql.y"
+  case 60: /* where: WHERE condition_list  */
+#line 479 "yacc_sql.y"
                            {
       (yyval.condition_list) = (yyvsp[0].condition_list);  
     }
-#line 2069 "yacc_sql.cpp"
+#line 2075 "yacc_sql.cpp"
     break;
 
-  case 60: /* condition_list: %empty  */
-#line 483 "yacc_sql.y"
+  case 61: /* condition_list: %empty  */
+#line 485 "yacc_sql.y"
     {
       (yyval.condition_list) = nullptr;
     }
-#line 2077 "yacc_sql.cpp"
+#line 2083 "yacc_sql.cpp"
     break;
 
-  case 61: /* condition_list: condition  */
-#line 486 "yacc_sql.y"
+  case 62: /* condition_list: condition  */
+#line 488 "yacc_sql.y"
                 {
       (yyval.condition_list) = new std::vector<Condition>;
       (yyval.condition_list)->emplace_back(*(yyvsp[0].condition));
       delete (yyvsp[0].condition);
     }
-#line 2087 "yacc_sql.cpp"
+#line 2093 "yacc_sql.cpp"
     break;
 
-  case 62: /* condition_list: condition AND condition_list  */
-#line 491 "yacc_sql.y"
+  case 63: /* condition_list: condition AND condition_list  */
+#line 493 "yacc_sql.y"
                                    {
       (yyval.condition_list) = (yyvsp[0].condition_list);
       (yyval.condition_list)->emplace_back(*(yyvsp[-2].condition));
       delete (yyvsp[-2].condition);
     }
-#line 2097 "yacc_sql.cpp"
+#line 2103 "yacc_sql.cpp"
     break;
 
-  case 63: /* condition: rel_attr comp_op value  */
-#line 499 "yacc_sql.y"
+  case 64: /* condition: rel_attr comp_op value  */
+#line 501 "yacc_sql.y"
     {
       (yyval.condition) = new Condition;
       (yyval.condition)->left_is_attr = 1;
@@ -2109,11 +2115,11 @@ yyreduce:
       delete (yyvsp[-2].rel_attr);
       delete (yyvsp[0].value);
     }
-#line 2113 "yacc_sql.cpp"
+#line 2119 "yacc_sql.cpp"
     break;
 
-  case 64: /* condition: value comp_op value  */
-#line 511 "yacc_sql.y"
+  case 65: /* condition: value comp_op value  */
+#line 513 "yacc_sql.y"
     {
       (yyval.condition) = new Condition;
       (yyval.condition)->left_is_attr = 0;
@@ -2125,11 +2131,11 @@ yyreduce:
       delete (yyvsp[-2].value);
       delete (yyvsp[0].value);
     }
-#line 2129 "yacc_sql.cpp"
+#line 2135 "yacc_sql.cpp"
     break;
 
-  case 65: /* condition: rel_attr comp_op rel_attr  */
-#line 523 "yacc_sql.y"
+  case 66: /* condition: rel_attr comp_op rel_attr  */
+#line 525 "yacc_sql.y"
     {
       (yyval.condition) = new Condition;
       (yyval.condition)->left_is_attr = 1;
@@ -2141,11 +2147,11 @@ yyreduce:
       delete (yyvsp[-2].rel_attr);
       delete (yyvsp[0].rel_attr);
     }
-#line 2145 "yacc_sql.cpp"
+#line 2151 "yacc_sql.cpp"
     break;
 
-  case 66: /* condition: value comp_op rel_attr  */
-#line 535 "yacc_sql.y"
+  case 67: /* condition: value comp_op rel_attr  */
+#line 537 "yacc_sql.y"
     {
       (yyval.condition) = new Condition;
       (yyval.condition)->left_is_attr = 0;
@@ -2157,67 +2163,79 @@ yyreduce:
       delete (yyvsp[-2].value);
       delete (yyvsp[0].rel_attr);
     }
-#line 2161 "yacc_sql.cpp"
+#line 2167 "yacc_sql.cpp"
     break;
 
-  case 67: /* comp_op: EQ  */
-#line 549 "yacc_sql.y"
+  case 68: /* comp_op: EQ  */
+#line 551 "yacc_sql.y"
          { (yyval.comp) = EQUAL_TO; }
-#line 2167 "yacc_sql.cpp"
+#line 2173 "yacc_sql.cpp"
     break;
 
-  case 68: /* comp_op: LT  */
-#line 550 "yacc_sql.y"
+  case 69: /* comp_op: LT  */
+#line 552 "yacc_sql.y"
          { (yyval.comp) = LESS_THAN; }
-#line 2173 "yacc_sql.cpp"
+#line 2179 "yacc_sql.cpp"
     break;
 
-  case 69: /* comp_op: GT  */
-#line 551 "yacc_sql.y"
+  case 70: /* comp_op: GT  */
+#line 553 "yacc_sql.y"
          { (yyval.comp) = GREAT_THAN; }
-#line 2179 "yacc_sql.cpp"
+#line 2185 "yacc_sql.cpp"
     break;
 
-  case 70: /* comp_op: LE  */
-#line 552 "yacc_sql.y"
+  case 71: /* comp_op: LE  */
+#line 554 "yacc_sql.y"
          { (yyval.comp) = LESS_EQUAL; }
-#line 2185 "yacc_sql.cpp"
+#line 2191 "yacc_sql.cpp"
     break;
 
-  case 71: /* comp_op: GE  */
-#line 553 "yacc_sql.y"
+  case 72: /* comp_op: GE  */
+#line 555 "yacc_sql.y"
          { (yyval.comp) = GREAT_EQUAL; }
-#line 2191 "yacc_sql.cpp"
+#line 2197 "yacc_sql.cpp"
     break;
 
-  case 72: /* comp_op: NE  */
-#line 554 "yacc_sql.y"
+  case 73: /* comp_op: NE  */
+#line 556 "yacc_sql.y"
          { (yyval.comp) = NOT_EQUAL; }
-#line 2197 "yacc_sql.cpp"
+#line 2203 "yacc_sql.cpp"
     break;
 
-  case 73: /* load_data: LOAD DATA INFILE SSS INTO TABLE ID  */
-#line 559 "yacc_sql.y"
+  case 74: /* load_data: LOAD DATA INFILE SSS INTO TABLE ID  */
+#line 561 "yacc_sql.y"
     {
       (yyval.command) = new Command(SCF_LOAD_DATA);
       (yyval.command)->load_data.relation_name = (yyvsp[0].string);
       (yyval.command)->load_data.file_name = (yyvsp[-3].string);
       free((yyvsp[0].string));
     }
-#line 2208 "yacc_sql.cpp"
+#line 2214 "yacc_sql.cpp"
     break;
 
-  case 74: /* explain: EXPLAIN command_wrapper  */
-#line 569 "yacc_sql.y"
+  case 75: /* explain: EXPLAIN command_wrapper  */
+#line 571 "yacc_sql.y"
     {
       (yyval.command) = new Command(SCF_EXPLAIN);
       (yyval.command)->explain.cmd = std::unique_ptr<Command>((yyvsp[0].command));
     }
-#line 2217 "yacc_sql.cpp"
+#line 2223 "yacc_sql.cpp"
+    break;
+
+  case 76: /* set_variable: SET ID EQ value  */
+#line 579 "yacc_sql.y"
+    {
+      (yyval.command) = new Command(SCF_SET_VARIABLE);
+      (yyval.command)->set_variable.name = (yyvsp[-2].string);
+      (yyval.command)->set_variable.value = *(yyvsp[0].value);
+      free((yyvsp[-2].string));
+      delete (yyvsp[0].value);
+    }
+#line 2235 "yacc_sql.cpp"
     break;
 
 
-#line 2221 "yacc_sql.cpp"
+#line 2239 "yacc_sql.cpp"
 
       default: break;
     }
@@ -2447,7 +2465,7 @@ yyreturn:
   return yyresult;
 }
 
-#line 578 "yacc_sql.y"
+#line 591 "yacc_sql.y"
 
 //_____________________________________________________________________
 extern void scan_string(const char *str, yyscan_t scanner);

src/observer/sql/parser/yacc_sql.y

@@ -132,6 +132,7 @@ int yyerror(YYLTYPE *llocp, ParsedSqlResult *sql_result, yyscan_t scanner, const
 %type <command> rollback
 %type <command> load_data
 %type <command> explain
+%type <command> set_variable
 %type <command> help
 %type <command> exit
 %type <command> command_wrapper
@@ -163,6 +164,7 @@ command_wrapper:
   | rollback
   | load_data
   | explain
+  | set_variable
   | help
   | exit
     ;
@@ -572,6 +574,17 @@ explain:
     }
     ;
 
+set_variable:
+    SET ID EQ value
+    {
+      $$ = new Command(SCF_SET_VARIABLE);
+      $$->set_variable.name = $2;
+      $$->set_variable.value = *$4;
+      free($2);
+      delete $4;
+    }
+    ;
+
 opt_semicolon: /*empty*/
     | SEMICOLON
     ;

src/observer/sql/stmt/create_table_stmt.cpp

@@ -13,9 +13,11 @@ See the Mulan PSL v2 for more details. */
 //
 
 #include "sql/stmt/create_table_stmt.h"
+#include "event/sql_debug.h"
 
 RC CreateTableStmt::create(Db *db, const CreateTable &create_table, Stmt *&stmt)
 {
   stmt = new CreateTableStmt(create_table.relation_name, create_table.attr_infos);
+  sql_debug("create table statement: table name %s", create_table.relation_name.c_str());
   return RC::SUCCESS;
 }

src/observer/event/optimize_event.h → src/observer/sql/stmt/set_variable_stmt.h

@@ -9,35 +9,39 @@ MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
 See the Mulan PSL v2 for more details. */
 
 //
-// Created by Wangyunlai on 2022/6/7.
+// Created by Wangyunlai on 2023/6/29.
 //
 
 #pragma once
 
-#include "common/seda/stage_event.h"
+#include <string>
+#include <vector>
 
-class SQLStageEvent;
-class Stmt;
+#include "sql/stmt/stmt.h"
 
-class OptimizeEvent : public common::StageEvent {
+/**
+ * @brief SetVairable 语句，设置变量，当前是会话变量，但是只有会话变量，没有全局变量
+ * @ingroup Statement
+ */
+class SetVariableStmt : public Stmt
+{
 public:
-  OptimizeEvent(SQLStageEvent *sql_event, common::StageEvent *parent_event)
-      : sql_event_(sql_event), parent_event_(parent_event)
+  SetVariableStmt(const SetVariable &set_variable) : set_variable_(set_variable)
   {}
+  virtual ~SetVariableStmt() = default;
 
-  virtual ~OptimizeEvent() noexcept = default;
+  StmtType type() const override { return StmtType::SET_VARIABLE; }
 
-  SQLStageEvent *sql_event() const
+  const char *var_name() const { return set_variable_.name.c_str(); }
+  const Value &var_value() const { return set_variable_.value; }
+  
+  static RC create(const SetVariable &set_variable, Stmt *&stmt)
   {
-    return sql_event_;
-  }
-
-  common::StageEvent *parent_event() const
-  {
-    return parent_event_;
+    /// 可以校验是否存在某个变量，但是这里忽略
+    stmt = new SetVariableStmt(set_variable);
+    return RC::SUCCESS;
   }
 
 private:
-  SQLStageEvent *sql_event_ = nullptr;
-  common::StageEvent *parent_event_ = nullptr;
-};
+  SetVariable set_variable_;
+};
\ No newline at end of file

src/observer/sql/stmt/stmt.cpp

@@ -26,6 +26,7 @@ See the Mulan PSL v2 for more details. */
 #include "sql/stmt/trx_begin_stmt.h"
 #include "sql/stmt/trx_end_stmt.h"
 #include "sql/stmt/exit_stmt.h"
+#include "sql/stmt/set_variable_stmt.h"
 
 RC Stmt::create_stmt(Db *db, const Command &cmd, Stmt *&stmt)
 {
@@ -79,6 +80,10 @@ RC Stmt::create_stmt(Db *db, const Command &cmd, Stmt *&stmt)
       return ExitStmt::create(stmt);
     }
 
+    case SCF_SET_VARIABLE: {
+      return SetVariableStmt::create(cmd.set_variable, stmt);
+    }
+
     default: {
       LOG_INFO("Command::type %d doesn't need to create statement.", cmd.flag);
     } break;

src/observer/sql/stmt/stmt.h

@@ -48,7 +48,8 @@ class Db;
   DEFINE_ENUM_ITEM(HELP)            \
   DEFINE_ENUM_ITEM(EXIT)            \
   DEFINE_ENUM_ITEM(EXPLAIN)         \
-  DEFINE_ENUM_ITEM(PREDICATE)
+  DEFINE_ENUM_ITEM(PREDICATE)       \
+  DEFINE_ENUM_ITEM(SET_VARIABLE)
 
 enum class StmtType {
   #define DEFINE_ENUM_ITEM(name)  name,

src/observer/storage/field/field.h

@@ -17,6 +17,10 @@ See the Mulan PSL v2 for more details. */
 #include "storage/table/table.h"
 #include "storage/field/field_meta.h"
 
+/**
+ * @brief 字段
+ * 
+ */
 class Field 
 {
 public:

src/observer/storage/field/field_meta.h

@@ -23,7 +23,10 @@ namespace Json {
 class Value;
 }  // namespace Json
 
-// Take care of shallow copy
+/**
+ * @brief 字段元数据
+ * 
+ */
 class FieldMeta 
 {
 public:

src/observer/storage/index/bplus_tree.h

@@ -34,9 +34,6 @@ See the Mulan PSL v2 for more details. */
  * @defgroup BPlusTree
  */
 
-#define EMPTY_RID_PAGE_NUM -1 // TODO remove me
-#define EMPTY_RID_SLOT_NUM -1
-
 /**
  * @brief B+树的操作类型
  * @ingroup BPlusTree
@@ -49,7 +46,7 @@ enum class BplusTreeOperationType
 };
 
 /**
- * @brief 属性比较
+ * @brief 属性比较(BplusTree)
  * @ingroup BPlusTree
  */
 class AttrComparator 
@@ -91,7 +88,8 @@ private:
 };
 
 /**
- * @brief 键值比较
+ * @brief 键值比较(BplusTree)
+ * @details BplusTree的键值除了字段属性，还有RID，是为了避免属性值重复而增加的。
  * @ingroup BPlusTree
  */
 class KeyComparator 
@@ -124,7 +122,7 @@ private:
 };
 
 /**
- * @brief 属性打印,调试使用
+ * @brief 属性打印,调试使用(BplusTree)
  * @ingroup BPlusTree
  */
 class AttrPrinter 
@@ -173,7 +171,7 @@ private:
 };
 
 /**
- * @brief 键值打印,调试使用
+ * @brief 键值打印,调试使用(BplusTree)
  * @ingroup BPlusTree
  */
 class KeyPrinter 
@@ -358,8 +356,7 @@ public:
 
   /**
    * 查找指定key的插入位置(注意不是key本身)
-   * 如果key已经存在，会设置found的值
-   * NOTE: 当前lookup的实现效率非常低，你是否可以优化它?
+   * 如果key已经存在，会设置found的值。
    */
   int lookup(const KeyComparator &comparator, const char *key, bool *found = nullptr) const;
 
@@ -418,11 +415,10 @@ public:
   /**
    * 与Leaf节点不同，lookup返回指定key应该属于哪个子节点，返回这个子节点在当前节点中的索引
    * 如果想要返回插入位置，就提供 `insert_position` 参数
-   * @param comparator 用于键值比较的函数
-   * @param key 查找的键值
-   * @param found 如果是有效指针，将会返回当前是否存在指定的键值
-   * @param insert_position 如果是有效指针，将会返回可以插入指定键值的位置
-   * NOTE: 查找效率不高，你可以优化它吗?
+   * @param[in] comparator 用于键值比较的函数
+   * @param[in] key 查找的键值
+   * @param[out] found 如果是有效指针，将会返回当前是否存在指定的键值
+   * @param[out] insert_position 如果是有效指针，将会返回可以插入指定键值的位置
    */
   int lookup(const KeyComparator &comparator, 
              const char *key, 

src/observer/storage/table/table.h

@@ -29,7 +29,10 @@ class IndexScanner;
 class RecordDeleter;
 class Trx;
 
-// TODO remove the routines with condition
+/**
+ * @brief 表
+ * 
+ */
 class Table 
 {
 public:

src/observer/storage/table/table_meta.h

@@ -22,6 +22,10 @@ See the Mulan PSL v2 for more details. */
 #include "storage/index/index_meta.h"
 #include "common/lang/serializable.h"
 
+/**
+ * @brief 表元数据
+ * 
+ */
 class TableMeta : public common::Serializable
 {
 public:

src/observer/storage/trx/mvcc_trx.h

@@ -55,8 +55,9 @@ private:
 };
 
 /**
+ * @brief 多版本并发事务
+ * @ingroup Transaction
  * TODO 没有垃圾回收
- * 
  */
 class MvccTrx : public Trx
 {