rocksdb/utilities/transactions/write_prepared_txn.h
Manuel Ung ea212e5316 WriteUnPrepared: Implement unprepared batches for transactions (#4104)
Summary:
This adds support for writing unprepared batches based on size defined in `TransactionOptions::max_write_batch_size`. This is done by overriding methods that modify data (Put/Delete/SingleDelete/Merge) and checking first if write batch size has exceeded threshold. If so, the write batch is written to DB as an unprepared batch.

Support for Commit/Rollback for unprepared batch is added as well. This has been done by simply extending the WritePrepared Commit/Rollback logic to take care of all unprep_seq numbers either when updating prepare heap, or adding to commit map. For updating the commit map, this logic exists inside `WriteUnpreparedCommitEntryPreReleaseCallback`.

A test change was also made to have transactions unregister themselves when committing without prepare. This is because with write unprepared, there may be unprepared entries (which act similarly to prepared entries) already when a commit is done without prepare.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4104

Differential Revision: D8785717

Pulled By: lth

fbshipit-source-id: c02006e281ec1ce00f628e2a7beec0ee73096a91
2018-07-24 00:13:18 -07:00

112 lines
4.0 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 <algorithm>
#include <atomic>
#include <mutex>
#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 "util/autovector.h"
#include "utilities/transactions/pessimistic_transaction.h"
#include "utilities/transactions/pessimistic_transaction_db.h"
#include "utilities/transactions/transaction_base.h"
#include "utilities/transactions/transaction_util.h"
namespace rocksdb {
class WritePreparedTxnDB;
// This impl could write to DB also uncommitted data and then later tell apart
// committed data from uncommitted data. Uncommitted data could be after the
// Prepare phase in 2PC (WritePreparedTxn) or before that
// (WriteUnpreparedTxnImpl).
class WritePreparedTxn : public PessimisticTransaction {
public:
WritePreparedTxn(WritePreparedTxnDB* db, const WriteOptions& write_options,
const TransactionOptions& txn_options);
virtual ~WritePreparedTxn() {}
// To make WAL commit markers visible, the snapshot will be based on the last
// seq in the WAL that is also published, LastPublishedSequence, as opposed to
// the last seq in the memtable.
using Transaction::Get;
virtual Status Get(const ReadOptions& options,
ColumnFamilyHandle* column_family, const Slice& key,
PinnableSlice* value) override;
// To make WAL commit markers visible, the snapshot will be based on the last
// seq in the WAL that is also published, LastPublishedSequence, as opposed to
// the last seq in the memtable.
using Transaction::GetIterator;
virtual Iterator* GetIterator(const ReadOptions& options) override;
virtual Iterator* GetIterator(const ReadOptions& options,
ColumnFamilyHandle* column_family) override;
virtual void SetSnapshot() override;
protected:
void Initialize(const TransactionOptions& txn_options) override;
// Override the protected SetId to make it visible to the friend class
// WritePreparedTxnDB
inline void SetId(uint64_t id) override { Transaction::SetId(id); }
private:
friend class WritePreparedTransactionTest_BasicRecoveryTest_Test;
friend class WritePreparedTxnDB;
friend class WriteUnpreparedTxnDB;
friend class WriteUnpreparedTxn;
Status PrepareInternal() override;
Status CommitWithoutPrepareInternal() override;
Status CommitBatchInternal(WriteBatch* batch, size_t batch_cnt) override;
// Since the data is already written to memtables at the Prepare phase, the
// commit entails writing only a commit marker in the WAL. The sequence number
// of the commit marker is then the commit timestamp of the transaction. To
// make WAL commit markers visible, the snapshot will be based on the last seq
// in the WAL that is also published, LastPublishedSequence, as opposed to the
// last seq in the memtable.
Status CommitInternal() override;
Status RollbackInternal() override;
virtual Status ValidateSnapshot(ColumnFamilyHandle* column_family,
const Slice& key,
SequenceNumber* tracked_at_seq) override;
virtual Status RebuildFromWriteBatch(WriteBatch* src_batch) override;
// No copying allowed
WritePreparedTxn(const WritePreparedTxn&);
void operator=(const WritePreparedTxn&);
WritePreparedTxnDB* wpt_db_;
// Number of sub-batches in prepare
size_t prepare_batch_cnt_ = 0;
};
} // namespace rocksdb
#endif // ROCKSDB_LITE