rocksdb/utilities/transactions/transaction_impl.h
agiardullo 20d1e547d1 Common base class for transactions
Summary:
As I keep adding new features to transactions, I keep creating more duplicate code.  This diff cleans this up by creating a base implementation class for Transaction and OptimisticTransaction to inherit from.

The code in TransactionBase.h/.cc is all just copied from elsewhere.  The only entertaining part of this class worth looking at is the virtual TryLock method which allows OptimisticTransactions and Transactions to share the same common code for Put/Get/etc.

The rest of this diff is mostly red and easy on the eyes.

Test Plan: No functionality change.  existing tests pass.

Reviewers: sdong, jkedgar, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45135
2015-08-24 19:09:43 -07:00

127 lines
3.5 KiB
C++

// Copyright (c) 2015, 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.
#pragma once
#ifndef ROCKSDB_LITE
#include <atomic>
#include <stack>
#include <string>
#include <unordered_map>
#include <vector>
#include "db/write_callback.h"
#include "rocksdb/db.h"
#include "rocksdb/slice.h"
#include "rocksdb/snapshot.h"
#include "rocksdb/status.h"
#include "rocksdb/types.h"
#include "rocksdb/utilities/transaction.h"
#include "rocksdb/utilities/transaction_db.h"
#include "rocksdb/utilities/write_batch_with_index.h"
#include "utilities/transactions/transaction_base.h"
#include "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();
Status Commit() override;
Status CommitBatch(WriteBatch* batch);
void Rollback() override;
// Generate a new unique transaction identifier
static TransactionID GenTxnID();
TransactionID GetTxnID() const { return txn_id_; }
// Returns the time (in milliseconds according to Env->GetMicros()*1000)
// 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 milliseconds 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) { lock_timeout_ = timeout; }
protected:
Status TryLock(ColumnFamilyHandle* column_family, const Slice& key,
bool untracked = false) override;
private:
TransactionDBImpl* txn_db_impl_;
// Used to create unique ids for transactions.
static std::atomic<TransactionID> txn_id_counter_;
// Unique ID for this transaction
const TransactionID txn_id_;
// If non-zero, this transaction should not be committed after this time (in
// milliseconds)
const uint64_t expiration_time_;
// Timeout in microseconds when locking a key or -1 if there is no timeout.
int64_t lock_timeout_;
// Map from column_family_id to map of keys to Sequence Numbers. Stores keys
// that have been locked.
// The key is known to not have been modified after the Sequence Number
// stored.
TransactionKeyMap tracked_keys_;
void Cleanup();
Status CheckKeySequence(ColumnFamilyHandle* column_family, const Slice& key);
Status LockBatch(WriteBatch* batch, TransactionKeyMap* keys_to_unlock);
Status DoCommit(WriteBatch* batch);
void RollbackLastN(size_t num);
// 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();
}
}
private:
TransactionImpl* txn_;
};
} // namespace rocksdb
#endif // ROCKSDB_LITE