rocksdb/utilities/transactions/write_prepared_txn.cc

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// 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::PrepareInternal() {
WriteOptions write_options = write_options_;
write_options.disableWAL = false;
WriteBatchInternal::MarkEndPrepare(GetWriteBatch()->GetWriteBatch(), name_);
const bool disable_memtable = true;
uint64_t seq_used = kMaxSequenceNumber;
Status s =
db_impl_->WriteImpl(write_options, GetWriteBatch()->GetWriteBatch(),
/*callback*/ nullptr, &log_number_, /*log ref*/ 0,
!disable_memtable, &seq_used);
assert(seq_used != kMaxSequenceNumber);
auto prepare_seq = seq_used;
SetId(prepare_seq);
wpt_db_->AddPrepared(prepare_seq);
return s;
}
Status WritePreparedTxn::CommitWithoutPrepareInternal() {
return CommitBatchInternal(GetWriteBatch()->GetWriteBatch());
}
Status WritePreparedTxn::CommitBatchInternal(WriteBatch* batch) {
// In the absense of Prepare markers, use Noop as a batch separator
WriteBatchInternal::InsertNoop(batch);
const bool disable_memtable = true;
const uint64_t no_log_ref = 0;
uint64_t seq_used = kMaxSequenceNumber;
auto s = db_impl_->WriteImpl(write_options_, batch, nullptr, nullptr,
no_log_ref, !disable_memtable, &seq_used);
assert(seq_used != kMaxSequenceNumber);
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 = kMaxSequenceNumber;
// Since the prepared batch is directly written to memtable, there is already
// a connection between the memtable and its WAL, so there is no need to
// redundantly reference the log that contains the prepared data.
const uint64_t zero_log_number = 0ull;
auto s = db_impl_->WriteImpl(write_options_, working_batch, nullptr, nullptr,
zero_log_number, disable_memtable, &seq_used);
assert(seq_used != kMaxSequenceNumber);
uint64_t& commit_seq = seq_used;
// TODO(myabandeh): Reject a commit request if AddCommitted cannot encode
// commit_seq. This happens if prep_seq <<< commit_seq.
auto prepare_seq = GetId();
wpt_db_->AddCommitted(prepare_seq, commit_seq);
return s;
}
Status WritePreparedTxn::RollbackInternal() {
WriteBatch rollback_batch;
assert(GetId() != kMaxSequenceNumber);
assert(GetId() > 0);
// In the absense of Prepare markers, use Noop as a batch separator
WriteBatchInternal::InsertNoop(&rollback_batch);
// In WritePrepared, the txn is is the same as prepare seq
auto last_visible_txn = GetId() - 1;
struct RollbackWriteBatchBuilder : public WriteBatch::Handler {
DBImpl* db_;
ReadOptions roptions;
WritePreparedTxnReadCallback callback;
WriteBatch* rollback_batch_;
RollbackWriteBatchBuilder(DBImpl* db, WritePreparedTxnDB* wpt_db,
SequenceNumber snap_seq, WriteBatch* dst_batch)
: db_(db), callback(wpt_db, snap_seq), rollback_batch_(dst_batch) {}
Status Rollback(uint32_t cf, const Slice& key) {
PinnableSlice pinnable_val;
bool not_used;
auto cf_handle = db_->GetColumnFamilyHandle(cf);
auto s = db_->GetImpl(roptions, cf_handle, key, &pinnable_val, &not_used,
&callback);
assert(s.ok() || s.IsNotFound());
if (s.ok()) {
s = rollback_batch_->Put(cf_handle, key, pinnable_val);
assert(s.ok());
} else if (s.IsNotFound()) {
// There has been no readable value before txn. By adding a delete we
// make sure that there will be none afterwards either.
s = rollback_batch_->Delete(cf_handle, key);
assert(s.ok());
} else {
// Unexpected status. Return it to the user.
}
return s;
}
Status PutCF(uint32_t cf, const Slice& key, const Slice& val) override {
return Rollback(cf, key);
}
Status DeleteCF(uint32_t cf, const Slice& key) override {
return Rollback(cf, key);
}
Status SingleDeleteCF(uint32_t cf, const Slice& key) override {
return Rollback(cf, key);
}
Status MergeCF(uint32_t cf, const Slice& key, const Slice& val) override {
return Rollback(cf, key);
}
Status MarkNoop(bool) override { return Status::OK(); }
Status MarkBeginPrepare() override { return Status::OK(); }
Status MarkEndPrepare(const Slice&) override { return Status::OK(); }
Status MarkCommit(const Slice&) override { return Status::OK(); }
Status MarkRollback(const Slice&) override {
return Status::InvalidArgument();
}
} rollback_handler(db_impl_, wpt_db_, last_visible_txn, &rollback_batch);
auto s = GetWriteBatch()->GetWriteBatch()->Iterate(&rollback_handler);
assert(s.ok());
if (!s.ok()) {
return s;
}
WriteBatchInternal::MarkRollback(&rollback_batch, name_);
const bool disable_memtable = true;
const uint64_t no_log_ref = 0;
uint64_t seq_used = kMaxSequenceNumber;
s = db_impl_->WriteImpl(write_options_, &rollback_batch, nullptr, nullptr,
no_log_ref, !disable_memtable, &seq_used);
assert(seq_used != kMaxSequenceNumber);
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);
// Mark the txn as rolled back
wpt_db_->RollbackPrepared(GetId(), commit_seq);
return s;
}
} // namespace rocksdb
#endif // ROCKSDB_LITE