60beefd6e0
Summary: By default the seq number in DB is increased once per written key. WritePrepared txns requires the seq to be increased once per the entire batch so that the seq would be used as the prepare timestamp by which the transaction is identified. Also we need to increase seq for the commit marker since it would give a unique id to the commit timestamp of transactions. Two unit tests are added to verify our understanding of how the seq should be increased. The recovery path requires much more work and is left to another patch. Closes https://github.com/facebook/rocksdb/pull/2885 Differential Revision: D5837843 Pulled By: maysamyabandeh fbshipit-source-id: a08960b93d727e1cf438c254d0c2636fb133cc1c
112 lines
4.1 KiB
C++
112 lines
4.1 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#ifndef ROCKSDB_LITE
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#include "utilities/transactions/write_prepared_txn.h"
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#include <map>
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#include "db/column_family.h"
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#include "db/db_impl.h"
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#include "rocksdb/db.h"
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#include "rocksdb/status.h"
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#include "rocksdb/utilities/transaction_db.h"
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#include "utilities/transactions/pessimistic_transaction.h"
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#include "utilities/transactions/pessimistic_transaction_db.h"
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namespace rocksdb {
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struct WriteOptions;
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WritePreparedTxn::WritePreparedTxn(WritePreparedTxnDB* txn_db,
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const WriteOptions& write_options,
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const TransactionOptions& txn_options)
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: PessimisticTransaction(txn_db, write_options, txn_options),
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wpt_db_(txn_db) {
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PessimisticTransaction::Initialize(txn_options);
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}
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Status WritePreparedTxn::Get(const ReadOptions& read_options,
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ColumnFamilyHandle* column_family,
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const Slice& key, PinnableSlice* pinnable_val) {
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auto snapshot = GetSnapshot();
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auto snap_seq =
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snapshot != nullptr ? snapshot->GetSequenceNumber() : kMaxSequenceNumber;
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WritePreparedTxnReadCallback callback(wpt_db_, snap_seq);
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return write_batch_.GetFromBatchAndDB(db_, read_options, column_family, key,
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pinnable_val, &callback);
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}
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Status WritePreparedTxn::PrepareInternal() {
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WriteOptions write_options = write_options_;
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write_options.disableWAL = false;
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WriteBatchInternal::MarkEndPrepare(GetWriteBatch()->GetWriteBatch(), name_);
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const bool disable_memtable = true;
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uint64_t seq_used = kMaxSequenceNumber;
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Status s =
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db_impl_->WriteImpl(write_options, GetWriteBatch()->GetWriteBatch(),
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/*callback*/ nullptr, &log_number_, /*log ref*/ 0,
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!disable_memtable, &seq_used);
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assert(seq_used != kMaxSequenceNumber);
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prepare_seq_ = seq_used;
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wpt_db_->AddPrepared(prepare_seq_);
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return s;
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}
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Status WritePreparedTxn::CommitWithoutPrepareInternal() {
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return CommitBatchInternal(GetWriteBatch()->GetWriteBatch());
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}
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Status WritePreparedTxn::CommitBatchInternal(WriteBatch* batch) {
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// In the absenese of Prepare markers, use Noop as a batch separator
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WriteBatchInternal::InsertNoop(batch);
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const bool disable_memtable = true;
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const uint64_t no_log_ref = 0;
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uint64_t seq_used;
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auto s = db_impl_->WriteImpl(write_options_, batch, nullptr, nullptr,
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no_log_ref, !disable_memtable, &seq_used);
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uint64_t& prepare_seq = seq_used;
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uint64_t& commit_seq = seq_used;
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// TODO(myabandeh): skip AddPrepared
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wpt_db_->AddPrepared(prepare_seq);
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wpt_db_->AddCommitted(prepare_seq, commit_seq);
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return s;
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}
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Status WritePreparedTxn::CommitInternal() {
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// We take the commit-time batch and append the Commit marker.
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// The Memtable will ignore the Commit marker in non-recovery mode
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WriteBatch* working_batch = GetCommitTimeWriteBatch();
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// TODO(myabandeh): prevent the users from writing to txn after the prepare
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// phase
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assert(working_batch->Count() == 0);
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WriteBatchInternal::MarkCommit(working_batch, name_);
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// any operations appended to this working_batch will be ignored from WAL
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working_batch->MarkWalTerminationPoint();
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const bool disable_memtable = true;
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uint64_t seq_used;
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auto s = db_impl_->WriteImpl(write_options_, working_batch, nullptr, nullptr,
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log_number_, disable_memtable, &seq_used);
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uint64_t& commit_seq = seq_used;
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// TODO(myabandeh): Reject a commit request if AddCommitted cannot encode
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// commit_seq. This happens if prep_seq <<< commit_seq.
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wpt_db_->AddCommitted(prepare_seq_, commit_seq);
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return s;
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}
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Status WritePreparedTxn::Rollback() {
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// TODO(myabandeh) Implement this
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throw std::runtime_error("Rollback not Implemented");
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return Status::OK();
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}
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} // namespace rocksdb
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#endif // ROCKSDB_LITE
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