rocksdb/utilities/transactions/write_prepared_txn.cc
Maysam Yabandeh f46464d383 write-prepared txn: call IsInSnapshot
Summary:
This patch instruments the read path to verify each read value against an optional ReadCallback class. If the value is rejected, the reader moves on to the next value. The WritePreparedTxn makes use of this feature to skip sequence numbers that are not in the read snapshot.
Closes https://github.com/facebook/rocksdb/pull/2850

Differential Revision: D5787375

Pulled By: maysamyabandeh

fbshipit-source-id: 49d808b3062ab35e7ae98ad388f659757794184c
2017-09-11 09:14:48 -07:00

113 lines
3.9 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).
#ifndef ROCKSDB_LITE
#include "utilities/transactions/write_prepared_txn.h"
#include <map>
#include "db/column_family.h"
#include "db/db_impl.h"
#include "rocksdb/db.h"
#include "rocksdb/status.h"
#include "rocksdb/utilities/transaction_db.h"
#include "utilities/transactions/pessimistic_transaction.h"
#include "utilities/transactions/pessimistic_transaction_db.h"
namespace rocksdb {
struct WriteOptions;
WritePreparedTxn::WritePreparedTxn(WritePreparedTxnDB* txn_db,
const WriteOptions& write_options,
const TransactionOptions& txn_options)
: PessimisticTransaction(txn_db, write_options, txn_options),
wpt_db_(txn_db) {
PessimisticTransaction::Initialize(txn_options);
}
Status WritePreparedTxn::Get(const ReadOptions& read_options,
ColumnFamilyHandle* column_family,
const Slice& key, PinnableSlice* pinnable_val) {
auto snapshot = GetSnapshot();
auto snap_seq =
snapshot != nullptr ? snapshot->GetSequenceNumber() : kMaxSequenceNumber;
WritePreparedTxnReadCallback callback(wpt_db_, snap_seq);
return write_batch_.GetFromBatchAndDB(db_, read_options, column_family, key,
pinnable_val, &callback);
}
Status WritePreparedTxn::CommitBatch(WriteBatch* /* unused */) {
// TODO(myabandeh) Implement this
throw std::runtime_error("CommitBatch not Implemented");
return Status::OK();
}
Status WritePreparedTxn::PrepareInternal() {
WriteOptions write_options = write_options_;
write_options.disableWAL = false;
WriteBatchInternal::MarkEndPrepare(GetWriteBatch()->GetWriteBatch(), name_);
const bool disable_memtable = true;
uint64_t seq_used;
Status s =
db_impl_->WriteImpl(write_options, GetWriteBatch()->GetWriteBatch(),
/*callback*/ nullptr, &log_number_, /*log ref*/ 0,
!disable_memtable, &seq_used);
prepare_seq_ = seq_used;
wpt_db_->AddPrepared(prepare_seq_);
return s;
}
Status WritePreparedTxn::CommitWithoutPrepareInternal() {
return CommitBatchInternal(GetWriteBatch()->GetWriteBatch());
}
Status WritePreparedTxn::CommitBatchInternal(WriteBatch* batch) {
const bool disable_memtable = true;
const uint64_t no_log_ref = 0;
uint64_t seq_used;
auto s = db_impl_->WriteImpl(write_options_, batch, nullptr, nullptr,
no_log_ref, !disable_memtable, &seq_used);
uint64_t& prepare_seq = seq_used;
uint64_t& commit_seq = seq_used;
// TODO(myabandeh): skip AddPrepared
wpt_db_->AddPrepared(prepare_seq);
wpt_db_->AddCommitted(prepare_seq, commit_seq);
return s;
}
Status WritePreparedTxn::CommitInternal() {
// We take the commit-time batch and append the Commit marker.
// The Memtable will ignore the Commit marker in non-recovery mode
WriteBatch* working_batch = GetCommitTimeWriteBatch();
// TODO(myabandeh): prevent the users from writing to txn after the prepare
// phase
assert(working_batch->Count() == 0);
WriteBatchInternal::MarkCommit(working_batch, name_);
// any operations appended to this working_batch will be ignored from WAL
working_batch->MarkWalTerminationPoint();
const bool disable_memtable = true;
uint64_t seq_used;
auto s = db_impl_->WriteImpl(write_options_, working_batch, nullptr, nullptr,
log_number_, disable_memtable, &seq_used);
uint64_t& commit_seq = seq_used;
wpt_db_->AddCommitted(prepare_seq_, commit_seq);
return s;
}
Status WritePreparedTxn::Rollback() {
// TODO(myabandeh) Implement this
throw std::runtime_error("Rollback not Implemented");
return Status::OK();
}
} // namespace rocksdb
#endif // ROCKSDB_LITE