Remove new first page when creating table

Signed-off-by: Wenbo Li <[email protected]>

src/catalog/simple_catalog.cpp

@@ -97,7 +97,8 @@ void SimpleCatalog::CreateTable(const std::string &table_name, const ColumnList
     Disk::CreateFile(Disk::GetFilePath(db_oid, oid));
   }
   name2oid_[table_name] = oid;
-  oid2table_[oid] = std::make_shared<Table>(buffer_pool_, log_manager_, oid, db_oid, column_list, new_table);
+  oid2table_[oid] = std::make_shared<Table>(buffer_pool_, log_manager_, oid, db_oid, column_list, new_table,
+                                            Disk::EmptyFile(Disk::GetFilePath(db_oid, oid)));
 
   // 检查：非新表不需要添加到Meta中
   if (!new_table) {

src/catalog/system_catalog.cpp

@@ -195,7 +195,8 @@ void SystemCatalog::CreateTable(const std::string &table_name, const ColumnList
   if (new_table) {
     Disk::CreateFile(Disk::GetFilePath(db_oid, oid));
   }
-  oid2table_[oid] = std::make_shared<Table>(buffer_pool_, log_manager_, oid, db_oid, column_list, new_table);
+  oid2table_[oid] = std::make_shared<Table>(buffer_pool_, log_manager_, oid, db_oid, column_list, new_table,
+                                            Disk::EmptyFile(Disk::GetFilePath(db_oid, oid)));
 
   // 检查：非新表不需要添加到 Meta 中
   if (!new_table) {
@@ -430,8 +431,8 @@ void SystemCatalog::LoadTableMeta() {
 
       // 添加数据表
       oid_manager_.SetEntryOid(OidType::TABLE, table_name, oid);
-      oid2table_[oid] =
-          std::make_shared<Table>(buffer_pool_, log_manager_, oid, current_database_oid_, column_list, false);
+      oid2table_[oid] = std::make_shared<Table>(buffer_pool_, log_manager_, oid, current_database_oid_, column_list,
+                                                false, Disk::EmptyFile(Disk::GetFilePath(GetDatabaseOid(oid), oid)));
       table2cardinality_[table_name] = cardinality;
     }
   }

src/log/log_manager.cpp

@@ -32,7 +32,7 @@ lsn_t LogManager::AppendInsertLog(xid_t xid, oid_t oid, pageid_t page_id, slotid
   if (att_.find(xid) == att_.end()) {
     throw DbException(std::to_string(xid) + " does not exist in att (in AppendInsertLog)");
   }
-  auto log = std::make_shared<InsertLog>(NULL_LSN, xid, att_[xid], oid, page_id, slot_id, offset, size, new_record);
+  auto log = std::make_shared<InsertLog>(NULL_LSN, xid, att_.at(xid), oid, page_id, slot_id, offset, size, new_record);
   lsn_t lsn = next_lsn_.fetch_add(log->GetSize(), std::memory_order_relaxed);
   log->SetLSN(lsn);
   att_[xid] = lsn;
@@ -50,7 +50,7 @@ lsn_t LogManager::AppendDeleteLog(xid_t xid, oid_t oid, pageid_t page_id, slotid
   if (att_.find(xid) == att_.end()) {
     throw DbException(std::to_string(xid) + " does not exist in att (in AppendDeleteLog)");
   }
-  auto log = std::make_shared<DeleteLog>(NULL_LSN, xid, att_[xid], oid, page_id, slot_id);
+  auto log = std::make_shared<DeleteLog>(NULL_LSN, xid, att_.at(xid), oid, page_id, slot_id);
   lsn_t lsn = next_lsn_.fetch_add(log->GetSize(), std::memory_order_relaxed);
   log->SetLSN(lsn);
   att_[xid] = lsn;
@@ -72,7 +72,7 @@ lsn_t LogManager::AppendNewPageLog(xid_t xid, oid_t oid, pageid_t prev_page_id,
   if (xid == DDL_XID) {
     log_xid = NULL_XID;
   } else {
-    log_xid = att_[xid];
+    log_xid = att_.at(xid);
   }
   auto log = std::make_shared<NewPageLog>(NULL_LSN, xid, log_xid, oid, prev_page_id, page_id);
   lsn_t lsn = next_lsn_.fetch_add(log->GetSize(), std::memory_order_relaxed);
@@ -113,7 +113,7 @@ lsn_t LogManager::AppendCommitLog(xid_t xid) {
   if (att_.find(xid) == att_.end()) {
     throw DbException(std::to_string(xid) + " does not exist in att (in AppendCommitLog)");
   }
-  auto log = std::make_shared<CommitLog>(NULL_LSN, xid, att_[xid]);
+  auto log = std::make_shared<CommitLog>(NULL_LSN, xid, att_.at(xid));
   lsn_t lsn = next_lsn_.fetch_add(log->GetSize(), std::memory_order_relaxed);
   log->SetLSN(lsn);
   {
@@ -129,7 +129,7 @@ lsn_t LogManager::AppendRollbackLog(xid_t xid) {
   if (att_.find(xid) == att_.end()) {
     throw DbException(std::to_string(xid) + " does not exist in att (in AppendRollbackLog)");
   }
-  auto log = std::make_shared<RollbackLog>(NULL_LSN, xid, att_[xid]);
+  auto log = std::make_shared<RollbackLog>(NULL_LSN, xid, att_.at(xid));
   lsn_t lsn = next_lsn_.fetch_add(log->GetSize(), std::memory_order_relaxed);
   log->SetLSN(lsn);
   {
@@ -246,6 +246,7 @@ void LogManager::Analyze() {
     in >> checkpoint_lsn;
   }
   // 根据 Checkpoint 日志恢复脏页表、活跃事务表等元信息
+  // 必要时调用 transaction_manager_.SetNextXid 来恢复事务 id
   // LAB 2 BEGIN
 }
 

src/storage/disk.cpp

@@ -49,6 +49,13 @@ void Disk::RemoveDirectory(const std::string &path) { std::filesystem::remove_al
 
 bool Disk::FileExists(const std::string &path) { return std::filesystem::is_regular_file(path); }
 
+bool Disk::EmptyFile(const std::string &path) {
+  if (!FileExists(path)) {
+    throw DbException("file " + path + " does not exist");
+  }
+  return std::filesystem::is_empty(path);
+}
+
 void Disk::CreateFile(const std::string &path) { std::ofstream ofs(path); }
 
 void Disk::RemoveFile(const std::string &path) { std::filesystem::remove(path); }
@@ -76,7 +83,7 @@ void Disk::ReadPage(const std::string &path, pageid_t page_id, char *data) {
   fs.seekg(page_id * DB_PAGE_SIZE);
   fs.read(data, DB_PAGE_SIZE);
   if (fs.gcount() != DB_PAGE_SIZE) {
-    throw DbException("read page failed: read " + std::to_string(fs.gcount()) + " bytes, expected " +
+    throw DbException(path + " read page failed: read " + std::to_string(fs.gcount()) + " bytes, expected " +
                       std::to_string(DB_PAGE_SIZE) + " bytes");
   }
 }

src/storage/disk.h

@@ -19,6 +19,8 @@ class Disk {
   static void RemoveDirectory(const std::string &path);
 
   static bool FileExists(const std::string &path);
+  static bool EmptyFile(const std::string &path);
+
   static void CreateFile(const std::string &path);
   static void RemoveFile(const std::string &path);
 

src/table/table.cpp

@@ -5,22 +5,18 @@
 namespace huadb {
 
 Table::Table(BufferPool &buffer_pool, LogManager &log_manager, oid_t oid, oid_t db_oid, ColumnList column_list,
-             bool new_table)
+             bool new_table, bool is_empty)
     : buffer_pool_(buffer_pool),
       log_manager_(log_manager),
       oid_(oid),
       db_oid_(db_oid),
       column_list_(std::move(column_list)) {
   // 新建表时初始化第一个页面
-  if (new_table) {
-    auto table_page = std::make_unique<TablePage>(buffer_pool_.NewPage(db_oid_, oid_, 0));
-    table_page->Init();
-    if (oid >= PRESERVED_OID) {
-      lsn_t lsn = log_manager_.AppendNewPageLog(DDL_XID, oid_, NULL_PAGE_ID, 0);
-      table_page->SetPageLSN(lsn);
-    }
+  if (new_table || is_empty) {
+    first_page_id_ = NULL_PAGE_ID;
+  } else {
+    first_page_id_ = 0;
   }
-  first_page_id_ = 0;
 }
 
 Rid Table::InsertRecord(std::shared_ptr<Record> record, xid_t xid, cid_t cid, bool write_log) {

src/table/table.h

@@ -11,7 +11,7 @@ namespace huadb {
 class Table {
  public:
   Table(BufferPool &buffer_pool, LogManager &log_manager, oid_t oid, oid_t db_oid, ColumnList column_list,
-        bool new_table);
+        bool new_table, bool is_empty);
 
   // 插入记录，返回插入记录的 rid
   // write_log: 是否写日志。系统表操作不写日志，用户表操作写日志，lab 2 相关参数