rocksdb/utilities/transactions/optimistic_transaction.h
Maysam Yabandeh eb6425303e Update WritePrepared with the pseudo code
Summary:
Implement the main body of WritePrepared pseudo code. This includes PrepareInternal and CommitInternal, as well as AddCommitted which updates the commit map. It also provides a IsInSnapshot method that could be later called form the read path to decide if a version is in the read snapshot or it should other be skipped.

This patch lacks unit tests and does not attempt to offer an efficient implementation. The idea is that to have the API specified so that we can work on related tasks in parallel.
Closes https://github.com/facebook/rocksdb/pull/2713

Differential Revision: D5640021

Pulled By: maysamyabandeh

fbshipit-source-id: bfa7a05e8d8498811fab714ce4b9c21530514e1c
2017-08-16 16:57:47 -07:00

99 lines
2.8 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#ifndef ROCKSDB_LITE
#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/optimistic_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 {
class OptimisticTransaction : public TransactionBaseImpl {
public:
OptimisticTransaction(OptimisticTransactionDB* db,
const WriteOptions& write_options,
const OptimisticTransactionOptions& txn_options);
virtual ~OptimisticTransaction();
void Reinitialize(OptimisticTransactionDB* txn_db,
const WriteOptions& write_options,
const OptimisticTransactionOptions& txn_options);
Status Prepare() override;
Status Commit() override;
Status Rollback() override;
Status SetName(const TransactionName& name) override;
protected:
Status TryLock(ColumnFamilyHandle* column_family, const Slice& key,
bool read_only, bool exclusive,
bool untracked = false) override;
private:
OptimisticTransactionDB* const txn_db_;
friend class OptimisticTransactionCallback;
void Initialize(const OptimisticTransactionOptions& txn_options);
// Returns OK if it is safe to commit this transaction. Returns Status::Busy
// if there are read or write conflicts that would prevent us from committing
// OR if we can not determine whether there would be any such conflicts.
//
// Should only be called on writer thread.
Status CheckTransactionForConflicts(DB* db);
void Clear() override;
void UnlockGetForUpdate(ColumnFamilyHandle* /* unused */,
const Slice& /* unused */) override {
// Nothing to unlock.
}
// No copying allowed
OptimisticTransaction(const OptimisticTransaction&);
void operator=(const OptimisticTransaction&);
};
// Used at commit time to trigger transaction validation
class OptimisticTransactionCallback : public WriteCallback {
public:
explicit OptimisticTransactionCallback(OptimisticTransaction* txn)
: txn_(txn) {}
Status Callback(DB* db) override {
return txn_->CheckTransactionForConflicts(db);
}
bool AllowWriteBatching() override { return false; }
private:
OptimisticTransaction* txn_;
};
} // namespace rocksdb
#endif // ROCKSDB_LITE