YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.

// This source code is licensed under the BSD-style license found in the

// LICENSE file in the root directory of this source tree. An additional grant

// of patent rights can be found in the PATENTS file in the same directory.

//

// The following only applies to changes made to this file as part of YugaByte development.

//

// Portions Copyright (c) YugaByte, Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except

// in compliance with the License.  You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software distributed under the License

// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

// or implied.  See the License for the specific language governing permissions and limitations

// under the License.

//

#ifndef ROCKSDB_UTILITIES_TRANSACTIONS_TRANSACTION_IMPL_H

#define ROCKSDB_UTILITIES_TRANSACTIONS_TRANSACTION_IMPL_H

#pragma once

#ifndef ROCKSDB_LITE

#include <atomic>

#include <stack>

#include <string>

#include <unordered_map>

#include <vector>

#include "yb/rocksdb/db/write_callback.h"

#include "yb/rocksdb/db.h"

#include "yb/util/slice.h"

#include "yb/rocksdb/snapshot.h"

#include "yb/rocksdb/status.h"

#include "yb/rocksdb/types.h"

#include "yb/rocksdb/utilities/transaction.h"

#include "yb/rocksdb/utilities/transaction_db.h"

#include "yb/rocksdb/utilities/write_batch_with_index.h"

#include "yb/rocksdb/utilities/transactions/transaction_base.h"

#include "yb/rocksdb/utilities/transactions/transaction_util.h"

namespace rocksdb {

using TransactionID = uint64_t;

class TransactionDBImpl;

class TransactionImpl : public TransactionBaseImpl {

 public:

  TransactionImpl(TransactionDB* db, const WriteOptions& write_options,

                  const TransactionOptions& txn_options);

  virtual ~TransactionImpl();

  void Reinitialize(TransactionDB* txn_db, const WriteOptions& write_options,

                    const TransactionOptions& txn_options);

  Status Commit() override;

  Status CommitBatch(WriteBatch* batch);

  void Rollback() override;

  Status RollbackToSavePoint() override;

  // Generate a new unique transaction identifier

  static TransactionID GenTxnID();

  TransactionID GetTxnID() const { return txn_id_; }

  // Returns the time (in microseconds according to Env->GetMicros())

  // that this transaction will be expired.  Returns 0 if this transaction does

  // not expire.

  uint64_t GetExpirationTime() const { return expiration_time_; }

  // returns true if this transaction has an expiration_time and has expired.

  bool IsExpired() const;

  // Returns the number of microseconds a transaction can wait on acquiring a

  // lock or -1 if there is no timeout.

  int64_t GetLockTimeout() const { return lock_timeout_; }

  void SetLockTimeout(int64_t timeout) override {

    lock_timeout_ = timeout * 1000;

  }

  // Returns true if locks were stolen successfully, false otherwise.

  bool TryStealingLocks();

 protected:

  Status TryLock(ColumnFamilyHandle* column_family, const Slice& key,

                 bool read_only, bool untracked = false) override;

 private:

  enum ExecutionStatus { STARTED, COMMITTING, LOCKS_STOLEN };

  TransactionDBImpl* txn_db_impl_;

  // Used to create unique ids for transactions.

  static std::atomic<TransactionID> txn_id_counter_;

  // Unique ID for this transaction

  TransactionID txn_id_;

  // If non-zero, this transaction should not be committed after this time (in

  // microseconds according to Env->NowMicros())

  uint64_t expiration_time_;

  // Timeout in microseconds when locking a key or -1 if there is no timeout.

  int64_t lock_timeout_;

  // Execution status of the transaction.

  std::atomic<ExecutionStatus> exec_status_;

  void Clear() override;

  void Initialize(const TransactionOptions& txn_options);

  Status ValidateSnapshot(ColumnFamilyHandle* column_family, const Slice& key,

                          SequenceNumber prev_seqno, SequenceNumber* new_seqno);

  Status LockBatch(WriteBatch* batch, TransactionKeyMap* keys_to_unlock);

  Status DoCommit(WriteBatch* batch);

  void RollbackLastN(size_t num);

  void UnlockGetForUpdate(ColumnFamilyHandle* column_family,

                          const Slice& key) override;

  // No copying allowed

  TransactionImpl(const TransactionImpl&);

  void operator=(const TransactionImpl&);

};

// Used at commit time to check whether transaction is committing before its

// expiration time.

class TransactionCallback : public WriteCallback {

 public:

  explicit TransactionCallback(TransactionImpl* txn) : txn_(txn) {}

  Status Callback(DB* db) override {

    if (txn_->IsExpired()) {

      return STATUS(Expired, "");

    } else {

      return Status::OK();

    }

  }

  bool AllowWriteBatching() override { return true; }

 private:

  TransactionImpl* txn_;

};

}  // namespace rocksdb

#endif  // ROCKSDB_LITE

#endif // ROCKSDB_UTILITIES_TRANSACTIONS_TRANSACTION_IMPL_H