Feat: Spring24 project4 starter code modification (#709)

* remove version link

Signed-off-by: AveryQi115 <[email protected]>

* add update tuple and undo link atomically

Signed-off-by: AveryQi115 <[email protected]>

* use new helper function

Signed-off-by: AveryQi115 <[email protected]>

---------

Signed-off-by: AveryQi115 <[email protected]>

Author: AveryQi115

src/concurrency/transaction_manager_impl.cpp

@@ -27,19 +27,6 @@ namespace bustub {
 
 auto TransactionManager::UpdateUndoLink(RID rid, std::optional<UndoLink> prev_link,
                                         std::function<bool(std::optional<UndoLink>)> &&check) -> bool {
-  std::function<bool(std::optional<VersionUndoLink>)> wrapper_func =
-      [check](std::optional<VersionUndoLink> link) -> bool {
-    if (link.has_value()) {
-      return check(link->prev_);
-    }
-    return check(std::nullopt);
-  };
-  return UpdateVersionLink(rid, prev_link.has_value() ? std::make_optional(VersionUndoLink{*prev_link}) : std::nullopt,
-                           check != nullptr ? wrapper_func : nullptr);
-}
-
-auto TransactionManager::UpdateVersionLink(RID rid, std::optional<VersionUndoLink> prev_version,
-                                           std::function<bool(std::optional<VersionUndoLink>)> &&check) -> bool {
   std::unique_lock<std::shared_mutex> lck(version_info_mutex_);
   std::shared_ptr<PageVersionInfo> pg_ver_info = nullptr;
   auto iter = version_info_.find(rid.GetPageId());
@@ -51,8 +38,8 @@ auto TransactionManager::UpdateVersionLink(RID rid, std::optional<VersionUndoLin
   }
   std::unique_lock<std::shared_mutex> lck2(pg_ver_info->mutex_);
   lck.unlock();
-  auto iter2 = pg_ver_info->prev_version_.find(rid.GetSlotNum());
-  if (iter2 == pg_ver_info->prev_version_.end()) {
+  auto iter2 = pg_ver_info->prev_link_.find(rid.GetSlotNum());
+  if (iter2 == pg_ver_info->prev_link_.end()) {
     if (check != nullptr && !check(std::nullopt)) {
       return false;
     }
@@ -61,15 +48,15 @@ auto TransactionManager::UpdateVersionLink(RID rid, std::optional<VersionUndoLin
       return false;
     }
   }
-  if (prev_version.has_value()) {
-    pg_ver_info->prev_version_[rid.GetSlotNum()] = *prev_version;
+  if (prev_link.has_value()) {
+    pg_ver_info->prev_link_[rid.GetSlotNum()] = *prev_link;
   } else {
-    pg_ver_info->prev_version_.erase(rid.GetSlotNum());
+    pg_ver_info->prev_link_.erase(rid.GetSlotNum());
   }
   return true;
 }
 
-auto TransactionManager::GetVersionLink(RID rid) -> std::optional<VersionUndoLink> {
+auto TransactionManager::GetUndoLink(RID rid) -> std::optional<UndoLink> {
   std::shared_lock<std::shared_mutex> lck(version_info_mutex_);
   auto iter = version_info_.find(rid.GetPageId());
   if (iter == version_info_.end()) {
@@ -78,21 +65,13 @@ auto TransactionManager::GetVersionLink(RID rid) -> std::optional<VersionUndoLin
   std::shared_ptr<PageVersionInfo> pg_ver_info = iter->second;
   std::unique_lock<std::shared_mutex> lck2(pg_ver_info->mutex_);
   lck.unlock();
-  auto iter2 = pg_ver_info->prev_version_.find(rid.GetSlotNum());
-  if (iter2 == pg_ver_info->prev_version_.end()) {
+  auto iter2 = pg_ver_info->prev_link_.find(rid.GetSlotNum());
+  if (iter2 == pg_ver_info->prev_link_.end()) {
     return std::nullopt;
   }
   return std::make_optional(iter2->second);
 }
 
-auto TransactionManager::GetUndoLink(RID rid) -> std::optional<UndoLink> {
-  auto version_link = GetVersionLink(rid);
-  if (version_link.has_value()) {
-    return version_link->prev_;
-  }
-  return std::nullopt;
-}
-
 auto TransactionManager::GetUndoLogOptional(UndoLink link) -> std::optional<UndoLog> {
   std::shared_lock<std::shared_mutex> lck(txn_map_mutex_);
   auto iter = txn_map_.find(link.prev_txn_);
@@ -122,4 +101,36 @@ void Transaction::SetTainted() {
   std::terminate();
 }
 
+auto UpdateTupleAndUndoLink(
+    TransactionManager *txn_mgr, RID rid, std::optional<UndoLink> undo_link, TableHeap *table_heap, Transaction *txn,
+    const TupleMeta &meta, const Tuple &tuple,
+    std::function<bool(const TupleMeta &meta, const Tuple &tuple, RID rid, std::optional<UndoLink>)> &&check) -> bool {
+  auto page_write_guard = table_heap->AcquireTablePageWriteLock(rid);
+  auto page = page_write_guard.AsMut<TablePage>();
+
+  auto [base_meta, base_tuple] = page->GetTuple(rid);
+  if (check != nullptr && !check(base_meta, base_tuple, rid, undo_link)) {
+    return false;
+  }
+
+  // Update tuple and tupleMeta if pass in tuple and meta are different
+  if (meta != base_meta || !IsTupleContentEqual(tuple, base_tuple)) {
+    table_heap->UpdateTupleInPlaceWithLockAcquired(meta, tuple, rid, page);
+  }
+
+  txn_mgr->UpdateUndoLink(rid, undo_link);
+
+  return true;
+}
+
+auto GetTupleAndUndoLink(TransactionManager *txn_mgr, TableHeap *table_heap, RID rid)
+    -> std::tuple<TupleMeta, Tuple, std::optional<UndoLink>> {
+  auto page_read_guard = table_heap->AcquireTablePageReadLock(rid);
+  auto page = page_read_guard.As<TablePage>();
+  auto [meta, tuple] = page->GetTuple(rid);
+
+  auto undo_link = txn_mgr->GetUndoLink(rid);
+  return std::make_tuple(meta, tuple, undo_link);
+}
+
 }  // namespace bustub

src/include/concurrency/transaction_manager.h

@@ -18,6 +18,7 @@
 #include <mutex>  // NOLINT
 #include <optional>
 #include <shared_mutex>
+#include <tuple>
 #include <unordered_map>
 #include <unordered_set>
 
@@ -26,32 +27,10 @@
 #include "concurrency/transaction.h"
 #include "concurrency/watermark.h"
 #include "recovery/log_manager.h"
+#include "storage/table/table_heap.h"
 #include "storage/table/tuple.h"
 
 namespace bustub {
-
-/// The first undo link in the version chain, that links table heap tuple to the undo log.
-struct VersionUndoLink {
-  /** The next version in the version chain. */
-  UndoLink prev_;
-  /** Whether a transaction is modifying the version link. Fall 2023: you do not need to read / write this field until
-   * task 4.2. */
-  bool in_progress_{false};
-
-  friend auto operator==(const VersionUndoLink &a, const VersionUndoLink &b) {
-    return a.prev_ == b.prev_ && a.in_progress_ == b.in_progress_;
-  }
-
-  friend auto operator!=(const VersionUndoLink &a, const VersionUndoLink &b) { return !(a == b); }
-
-  inline static auto FromOptionalUndoLink(std::optional<UndoLink> undo_link) -> std::optional<VersionUndoLink> {
-    if (undo_link.has_value()) {
-      return VersionUndoLink{*undo_link};
-    }
-    return std::nullopt;
-  }
-};
-
 /**
  * TransactionManager keeps track of all the transactions running in the system.
  */
@@ -81,25 +60,15 @@ class TransactionManager {
   void Abort(Transaction *txn);
 
   /**
-   * @brief Use this function before task 4.2. Update an undo link that links table heap tuple to the first undo log.
+   * @brief Update an undo link that links table heap tuple to the first undo log.
    * Before updating, `check` function will be called to ensure validity.
    */
   auto UpdateUndoLink(RID rid, std::optional<UndoLink> prev_link,
                       std::function<bool(std::optional<UndoLink>)> &&check = nullptr) -> bool;
 
-  /**
-   * @brief Use this function after task 4.2. Update an undo link that links table heap tuple to the first undo log.
-   * Before updating, `check` function will be called to ensure validity.
-   */
-  auto UpdateVersionLink(RID rid, std::optional<VersionUndoLink> prev_version,
-                         std::function<bool(std::optional<VersionUndoLink>)> &&check = nullptr) -> bool;
-
-  /** @brief Get the first undo log of a table heap tuple. Use this before task 4.2 */
+  /** @brief Get the first undo log of a table heap tuple. */
   auto GetUndoLink(RID rid) -> std::optional<UndoLink>;
 
-  /** @brief Get the first undo log of a table heap tuple. Use this after task 4.2 */
-  auto GetVersionLink(RID rid) -> std::optional<VersionUndoLink>;
-
   /** @brief Access the transaction undo log buffer and get the undo log. Return nullopt if the txn does not exist. Will
    * still throw an exception if the index is out of range. */
   auto GetUndoLogOptional(UndoLink link) -> std::optional<UndoLog>;
@@ -127,7 +96,7 @@ class TransactionManager {
     /** Stores previous version info for all slots. Note: DO NOT use `[x]` to access it because
      * it will create new elements even if it does not exist. Use `find` instead.
      */
-    std::unordered_map<slot_offset_t, VersionUndoLink> prev_version_;
+    std::unordered_map<slot_offset_t, UndoLink> prev_link_;
   };
 
   /** protects version info */
@@ -155,4 +124,19 @@ class TransactionManager {
   auto VerifyTxn(Transaction *txn) -> bool;
 };
 
+/**
+ * @brief Update the tuple and its undo link in the table heap atomically.
+ */
+auto UpdateTupleAndUndoLink(
+    TransactionManager *txn_mgr, RID rid, std::optional<UndoLink> undo_link, TableHeap *table_heap, Transaction *txn,
+    const TupleMeta &meta, const Tuple &tuple,
+    std::function<bool(const TupleMeta &meta, const Tuple &tuple, RID rid, std::optional<UndoLink>)> &&check = nullptr)
+    -> bool;
+
+/**
+ * @brief Get the tuple and its undo link in the table heap atomically.
+ */
+auto GetTupleAndUndoLink(TransactionManager *txn_mgr, TableHeap *table_heap, RID rid)
+    -> std::tuple<TupleMeta, Tuple, std::optional<UndoLink>>;
+
 }  // namespace bustub

test/txn/txn_scan_test.cpp

@@ -188,16 +188,16 @@ TEST(TxnScanTest, DISABLED_ScanTest) {  // NOLINT
 
   auto rid1 = *table_info->table_->InsertTuple(TupleMeta{txn4->GetTransactionTempTs(), false},
                                                Tuple{{Int(1), DoubleNull(), BoolNull()}, schema.get()});
-  bustub->txn_manager_->UpdateVersionLink(rid1, VersionUndoLink{prev_log_1}, nullptr);
+  bustub->txn_manager_->UpdateUndoLink(rid1, prev_log_1, nullptr);
   auto rid2 = *table_info->table_->InsertTuple(TupleMeta{txn3->GetReadTs(), false},
                                                Tuple{{Int(3), DoubleNull(), BoolNull()}, schema.get()});
-  bustub->txn_manager_->UpdateVersionLink(rid2, VersionUndoLink{prev_log_2}, nullptr);
+  bustub->txn_manager_->UpdateUndoLink(rid2, prev_log_2, nullptr);
   auto rid3 = *table_info->table_->InsertTuple(TupleMeta{txn4->GetReadTs(), true},
                                                Tuple{{IntNull(), DoubleNull(), BoolNull()}, schema.get()});
-  bustub->txn_manager_->UpdateVersionLink(rid3, VersionUndoLink{prev_log_4}, nullptr);
+  bustub->txn_manager_->UpdateUndoLink(rid3, prev_log_4, nullptr);
   auto rid4 = *table_info->table_->InsertTuple(TupleMeta{txn3->GetTransactionTempTs(), true},
                                                Tuple{{IntNull(), DoubleNull(), BoolNull()}, schema.get()});
-  bustub->txn_manager_->UpdateVersionLink(rid4, VersionUndoLink{prev_log_5}, nullptr);
+  bustub->txn_manager_->UpdateUndoLink(rid4, prev_log_5, nullptr);
 
   TxnMgrDbg("before verify scan", bustub->txn_manager_.get(), table_info, table_info->table_.get());