rocksdb/utilities/transactions/transaction_impl.h

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// 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.
#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;
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
const TransactionID txn_id_;
// If non-zero, this transaction should not be committed after this time (in
// microseconds according to Env->NowMicros())
const 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;
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