d6e1e6f37a
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/9537 Add `Transaction::SetReadTimestampForValidation()` and `Transaction::SetCommitTimestamp()` APIs with default implementation returning `Status::NotSupported()`. Currently, calling these two APIs do not have any effect. Also add checks to `PessimisticTransactionDB` to enforce that column families in the same db either - disable user-defined timestamp - enable 64-bit timestamp Just to clarify, a `PessimisticTransactionDB` can have some column families without timestamps as well as column families that enable timestamp. Each `PessimisticTransaction` can have two optional timestamps, `read_timestamp_` used for additional validation and `commit_timestamp_` which denotes when the transaction commits. For now, we are going to support `WriteCommittedTxn` (in a series of subsequent PRs) Once set, we do not allow decreasing `read_timestamp_`. The `commit_timestamp_` must be greater than `read_timestamp_` for each transaction and must be set before commit, unless the transaction does not involve any column family that enables user-defined timestamp. TransactionDB builds on top of RocksDB core `DB` layer. Though `DB` layer assumes that user-defined timestamps are byte arrays, `TransactionDB` uses uint64_t to store timestamps. When they are passed down, they are still interpreted as byte-arrays by `DB`. Reviewed By: ltamasi Differential Revision: D31567959 fbshipit-source-id: b0b6b69acab5d8e340cf174f33e8b09f1c3d3502
782 lines
26 KiB
C++
782 lines
26 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/pessimistic_transaction.h"
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#include <map>
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#include <set>
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#include <string>
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#include <vector>
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#include "db/column_family.h"
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#include "db/db_impl/db_impl.h"
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#include "logging/logging.h"
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#include "rocksdb/comparator.h"
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#include "rocksdb/db.h"
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#include "rocksdb/snapshot.h"
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#include "rocksdb/status.h"
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#include "rocksdb/utilities/transaction_db.h"
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#include "test_util/sync_point.h"
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#include "util/cast_util.h"
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#include "util/string_util.h"
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#include "utilities/transactions/pessimistic_transaction_db.h"
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#include "utilities/transactions/transaction_util.h"
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namespace ROCKSDB_NAMESPACE {
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struct WriteOptions;
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std::atomic<TransactionID> PessimisticTransaction::txn_id_counter_(1);
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TransactionID PessimisticTransaction::GenTxnID() {
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return txn_id_counter_.fetch_add(1);
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}
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PessimisticTransaction::PessimisticTransaction(
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TransactionDB* txn_db, const WriteOptions& write_options,
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const TransactionOptions& txn_options, const bool init)
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: TransactionBaseImpl(
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txn_db->GetRootDB(), write_options,
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static_cast_with_check<PessimisticTransactionDB>(txn_db)
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->GetLockTrackerFactory()),
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txn_db_impl_(nullptr),
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expiration_time_(0),
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txn_id_(0),
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waiting_cf_id_(0),
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waiting_key_(nullptr),
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lock_timeout_(0),
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deadlock_detect_(false),
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deadlock_detect_depth_(0),
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skip_concurrency_control_(false) {
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txn_db_impl_ = static_cast_with_check<PessimisticTransactionDB>(txn_db);
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db_impl_ = static_cast_with_check<DBImpl>(db_);
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if (init) {
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Initialize(txn_options);
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}
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}
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void PessimisticTransaction::Initialize(const TransactionOptions& txn_options) {
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txn_id_ = GenTxnID();
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txn_state_ = STARTED;
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deadlock_detect_ = txn_options.deadlock_detect;
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deadlock_detect_depth_ = txn_options.deadlock_detect_depth;
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write_batch_.SetMaxBytes(txn_options.max_write_batch_size);
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skip_concurrency_control_ = txn_options.skip_concurrency_control;
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lock_timeout_ = txn_options.lock_timeout * 1000;
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if (lock_timeout_ < 0) {
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// Lock timeout not set, use default
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lock_timeout_ =
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txn_db_impl_->GetTxnDBOptions().transaction_lock_timeout * 1000;
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}
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if (txn_options.expiration >= 0) {
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expiration_time_ = start_time_ + txn_options.expiration * 1000;
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} else {
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expiration_time_ = 0;
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}
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if (txn_options.set_snapshot) {
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SetSnapshot();
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}
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if (expiration_time_ > 0) {
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txn_db_impl_->InsertExpirableTransaction(txn_id_, this);
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}
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use_only_the_last_commit_time_batch_for_recovery_ =
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txn_options.use_only_the_last_commit_time_batch_for_recovery;
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skip_prepare_ = txn_options.skip_prepare;
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}
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PessimisticTransaction::~PessimisticTransaction() {
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txn_db_impl_->UnLock(this, *tracked_locks_);
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if (expiration_time_ > 0) {
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txn_db_impl_->RemoveExpirableTransaction(txn_id_);
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}
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if (!name_.empty() && txn_state_ != COMMITTED) {
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txn_db_impl_->UnregisterTransaction(this);
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}
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}
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void PessimisticTransaction::Clear() {
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txn_db_impl_->UnLock(this, *tracked_locks_);
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TransactionBaseImpl::Clear();
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}
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void PessimisticTransaction::Reinitialize(
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TransactionDB* txn_db, const WriteOptions& write_options,
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const TransactionOptions& txn_options) {
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if (!name_.empty() && txn_state_ != COMMITTED) {
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txn_db_impl_->UnregisterTransaction(this);
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}
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TransactionBaseImpl::Reinitialize(txn_db->GetRootDB(), write_options);
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Initialize(txn_options);
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}
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bool PessimisticTransaction::IsExpired() const {
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if (expiration_time_ > 0) {
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if (dbimpl_->GetSystemClock()->NowMicros() >= expiration_time_) {
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// Transaction is expired.
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return true;
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}
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}
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return false;
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}
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WriteCommittedTxn::WriteCommittedTxn(TransactionDB* 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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Status WriteCommittedTxn::SetReadTimestampForValidation(TxnTimestamp ts) {
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if (read_timestamp_ < kMaxTxnTimestamp && ts < read_timestamp_) {
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return Status::InvalidArgument(
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"Cannot decrease read timestamp for validation");
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}
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read_timestamp_ = ts;
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return Status::OK();
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}
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Status WriteCommittedTxn::SetCommitTimestamp(TxnTimestamp ts) {
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if (read_timestamp_ < kMaxTxnTimestamp && ts <= read_timestamp_) {
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return Status::InvalidArgument(
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"Cannot commit at timestamp smaller than or equal to read timestamp");
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}
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commit_timestamp_ = ts;
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return Status::OK();
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}
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Status PessimisticTransaction::CommitBatch(WriteBatch* batch) {
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std::unique_ptr<LockTracker> keys_to_unlock(lock_tracker_factory_.Create());
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Status s = LockBatch(batch, keys_to_unlock.get());
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if (!s.ok()) {
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return s;
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}
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bool can_commit = false;
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if (IsExpired()) {
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s = Status::Expired();
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} else if (expiration_time_ > 0) {
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TransactionState expected = STARTED;
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can_commit = std::atomic_compare_exchange_strong(&txn_state_, &expected,
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AWAITING_COMMIT);
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} else if (txn_state_ == STARTED) {
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// lock stealing is not a concern
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can_commit = true;
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}
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if (can_commit) {
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txn_state_.store(AWAITING_COMMIT);
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s = CommitBatchInternal(batch);
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if (s.ok()) {
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txn_state_.store(COMMITTED);
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}
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} else if (txn_state_ == LOCKS_STOLEN) {
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s = Status::Expired();
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} else {
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s = Status::InvalidArgument("Transaction is not in state for commit.");
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}
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txn_db_impl_->UnLock(this, *keys_to_unlock);
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return s;
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}
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Status PessimisticTransaction::Prepare() {
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if (name_.empty()) {
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return Status::InvalidArgument(
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"Cannot prepare a transaction that has not been named.");
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}
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if (IsExpired()) {
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return Status::Expired();
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}
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Status s;
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bool can_prepare = false;
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if (expiration_time_ > 0) {
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// must concern ourselves with expiraton and/or lock stealing
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// need to compare/exchange bc locks could be stolen under us here
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TransactionState expected = STARTED;
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can_prepare = std::atomic_compare_exchange_strong(&txn_state_, &expected,
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AWAITING_PREPARE);
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} else if (txn_state_ == STARTED) {
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// expiration and lock stealing is not possible
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txn_state_.store(AWAITING_PREPARE);
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can_prepare = true;
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}
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if (can_prepare) {
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// transaction can't expire after preparation
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expiration_time_ = 0;
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assert(log_number_ == 0 ||
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txn_db_impl_->GetTxnDBOptions().write_policy == WRITE_UNPREPARED);
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s = PrepareInternal();
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if (s.ok()) {
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txn_state_.store(PREPARED);
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}
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} else if (txn_state_ == LOCKS_STOLEN) {
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s = Status::Expired();
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} else if (txn_state_ == PREPARED) {
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s = Status::InvalidArgument("Transaction has already been prepared.");
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} else if (txn_state_ == COMMITTED) {
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s = Status::InvalidArgument("Transaction has already been committed.");
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} else if (txn_state_ == ROLLEDBACK) {
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s = Status::InvalidArgument("Transaction has already been rolledback.");
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} else {
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s = Status::InvalidArgument("Transaction is not in state for commit.");
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}
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return s;
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}
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Status WriteCommittedTxn::PrepareInternal() {
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WriteOptions write_options = write_options_;
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write_options.disableWAL = false;
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auto s = WriteBatchInternal::MarkEndPrepare(GetWriteBatch()->GetWriteBatch(),
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name_);
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assert(s.ok());
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class MarkLogCallback : public PreReleaseCallback {
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public:
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MarkLogCallback(DBImpl* db, bool two_write_queues)
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: db_(db), two_write_queues_(two_write_queues) {
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(void)two_write_queues_; // to silence unused private field warning
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}
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virtual Status Callback(SequenceNumber, bool is_mem_disabled,
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uint64_t log_number, size_t /*index*/,
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size_t /*total*/) override {
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#ifdef NDEBUG
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(void)is_mem_disabled;
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#endif
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assert(log_number != 0);
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assert(!two_write_queues_ || is_mem_disabled); // implies the 2nd queue
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db_->logs_with_prep_tracker()->MarkLogAsContainingPrepSection(log_number);
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return Status::OK();
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}
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private:
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DBImpl* db_;
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bool two_write_queues_;
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} mark_log_callback(db_impl_,
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db_impl_->immutable_db_options().two_write_queues);
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WriteCallback* const kNoWriteCallback = nullptr;
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const uint64_t kRefNoLog = 0;
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const bool kDisableMemtable = true;
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SequenceNumber* const KIgnoreSeqUsed = nullptr;
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const size_t kNoBatchCount = 0;
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s = db_impl_->WriteImpl(write_options, GetWriteBatch()->GetWriteBatch(),
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kNoWriteCallback, &log_number_, kRefNoLog,
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kDisableMemtable, KIgnoreSeqUsed, kNoBatchCount,
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&mark_log_callback);
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return s;
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}
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Status PessimisticTransaction::Commit() {
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bool commit_without_prepare = false;
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bool commit_prepared = false;
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if (IsExpired()) {
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return Status::Expired();
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}
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if (expiration_time_ > 0) {
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// we must atomicaly compare and exchange the state here because at
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// this state in the transaction it is possible for another thread
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// to change our state out from under us in the even that we expire and have
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// our locks stolen. In this case the only valid state is STARTED because
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// a state of PREPARED would have a cleared expiration_time_.
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TransactionState expected = STARTED;
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commit_without_prepare = std::atomic_compare_exchange_strong(
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&txn_state_, &expected, AWAITING_COMMIT);
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TEST_SYNC_POINT("TransactionTest::ExpirableTransactionDataRace:1");
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} else if (txn_state_ == PREPARED) {
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// expiration and lock stealing is not a concern
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commit_prepared = true;
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} else if (txn_state_ == STARTED) {
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// expiration and lock stealing is not a concern
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if (skip_prepare_) {
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commit_without_prepare = true;
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} else {
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return Status::TxnNotPrepared();
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}
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}
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Status s;
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if (commit_without_prepare) {
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assert(!commit_prepared);
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if (WriteBatchInternal::Count(GetCommitTimeWriteBatch()) > 0) {
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s = Status::InvalidArgument(
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"Commit-time batch contains values that will not be committed.");
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} else {
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txn_state_.store(AWAITING_COMMIT);
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if (log_number_ > 0) {
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dbimpl_->logs_with_prep_tracker()->MarkLogAsHavingPrepSectionFlushed(
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log_number_);
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}
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s = CommitWithoutPrepareInternal();
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if (!name_.empty()) {
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txn_db_impl_->UnregisterTransaction(this);
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}
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Clear();
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if (s.ok()) {
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txn_state_.store(COMMITTED);
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}
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}
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} else if (commit_prepared) {
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txn_state_.store(AWAITING_COMMIT);
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s = CommitInternal();
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if (!s.ok()) {
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ROCKS_LOG_WARN(db_impl_->immutable_db_options().info_log,
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"Commit write failed");
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return s;
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}
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// FindObsoleteFiles must now look to the memtables
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// to determine what prep logs must be kept around,
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// not the prep section heap.
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assert(log_number_ > 0);
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dbimpl_->logs_with_prep_tracker()->MarkLogAsHavingPrepSectionFlushed(
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log_number_);
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txn_db_impl_->UnregisterTransaction(this);
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Clear();
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txn_state_.store(COMMITTED);
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} else if (txn_state_ == LOCKS_STOLEN) {
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s = Status::Expired();
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} else if (txn_state_ == COMMITTED) {
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s = Status::InvalidArgument("Transaction has already been committed.");
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} else if (txn_state_ == ROLLEDBACK) {
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s = Status::InvalidArgument("Transaction has already been rolledback.");
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} else {
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s = Status::InvalidArgument("Transaction is not in state for commit.");
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}
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return s;
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}
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Status WriteCommittedTxn::CommitWithoutPrepareInternal() {
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uint64_t seq_used = kMaxSequenceNumber;
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auto s =
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db_impl_->WriteImpl(write_options_, GetWriteBatch()->GetWriteBatch(),
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/*callback*/ nullptr, /*log_used*/ nullptr,
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/*log_ref*/ 0, /*disable_memtable*/ false, &seq_used);
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assert(!s.ok() || seq_used != kMaxSequenceNumber);
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if (s.ok()) {
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SetId(seq_used);
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}
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return s;
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}
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Status WriteCommittedTxn::CommitBatchInternal(WriteBatch* batch, size_t) {
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uint64_t seq_used = kMaxSequenceNumber;
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auto s = db_impl_->WriteImpl(write_options_, batch, /*callback*/ nullptr,
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/*log_used*/ nullptr, /*log_ref*/ 0,
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/*disable_memtable*/ false, &seq_used);
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assert(!s.ok() || seq_used != kMaxSequenceNumber);
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if (s.ok()) {
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SetId(seq_used);
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}
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return s;
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}
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Status WriteCommittedTxn::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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auto s = WriteBatchInternal::MarkCommit(working_batch, name_);
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assert(s.ok());
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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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// insert prepared batch into Memtable only skipping WAL.
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// Memtable will ignore BeginPrepare/EndPrepare markers
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// in non recovery mode and simply insert the values
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s = WriteBatchInternal::Append(working_batch,
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GetWriteBatch()->GetWriteBatch());
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assert(s.ok());
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uint64_t seq_used = kMaxSequenceNumber;
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s = db_impl_->WriteImpl(write_options_, working_batch, /*callback*/ nullptr,
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/*log_used*/ nullptr, /*log_ref*/ log_number_,
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/*disable_memtable*/ false, &seq_used);
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assert(!s.ok() || seq_used != kMaxSequenceNumber);
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if (s.ok()) {
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SetId(seq_used);
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}
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return s;
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}
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Status PessimisticTransaction::Rollback() {
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Status s;
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if (txn_state_ == PREPARED) {
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txn_state_.store(AWAITING_ROLLBACK);
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s = RollbackInternal();
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if (s.ok()) {
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// we do not need to keep our prepared section around
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assert(log_number_ > 0);
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dbimpl_->logs_with_prep_tracker()->MarkLogAsHavingPrepSectionFlushed(
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log_number_);
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Clear();
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txn_state_.store(ROLLEDBACK);
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}
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} else if (txn_state_ == STARTED) {
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if (log_number_ > 0) {
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assert(txn_db_impl_->GetTxnDBOptions().write_policy == WRITE_UNPREPARED);
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assert(GetId() > 0);
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s = RollbackInternal();
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if (s.ok()) {
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dbimpl_->logs_with_prep_tracker()->MarkLogAsHavingPrepSectionFlushed(
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log_number_);
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}
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}
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// prepare couldn't have taken place
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Clear();
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} else if (txn_state_ == COMMITTED) {
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s = Status::InvalidArgument("This transaction has already been committed.");
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} else {
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s = Status::InvalidArgument(
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"Two phase transaction is not in state for rollback.");
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}
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return s;
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}
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Status WriteCommittedTxn::RollbackInternal() {
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WriteBatch rollback_marker;
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auto s = WriteBatchInternal::MarkRollback(&rollback_marker, name_);
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assert(s.ok());
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s = db_impl_->WriteImpl(write_options_, &rollback_marker);
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return s;
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}
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Status PessimisticTransaction::RollbackToSavePoint() {
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if (txn_state_ != STARTED) {
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return Status::InvalidArgument("Transaction is beyond state for rollback.");
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}
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if (save_points_ != nullptr && !save_points_->empty()) {
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// Unlock any keys locked since last transaction
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auto& save_point_tracker = *save_points_->top().new_locks_;
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std::unique_ptr<LockTracker> t(
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|
tracked_locks_->GetTrackedLocksSinceSavePoint(save_point_tracker));
|
|
if (t) {
|
|
txn_db_impl_->UnLock(this, *t);
|
|
}
|
|
}
|
|
|
|
return TransactionBaseImpl::RollbackToSavePoint();
|
|
}
|
|
|
|
// Lock all keys in this batch.
|
|
// On success, caller should unlock keys_to_unlock
|
|
Status PessimisticTransaction::LockBatch(WriteBatch* batch,
|
|
LockTracker* keys_to_unlock) {
|
|
class Handler : public WriteBatch::Handler {
|
|
public:
|
|
// Sorted map of column_family_id to sorted set of keys.
|
|
// Since LockBatch() always locks keys in sorted order, it cannot deadlock
|
|
// with itself. We're not using a comparator here since it doesn't matter
|
|
// what the sorting is as long as it's consistent.
|
|
std::map<uint32_t, std::set<std::string>> keys_;
|
|
|
|
Handler() {}
|
|
|
|
void RecordKey(uint32_t column_family_id, const Slice& key) {
|
|
std::string key_str = key.ToString();
|
|
|
|
auto& cfh_keys = keys_[column_family_id];
|
|
auto iter = cfh_keys.find(key_str);
|
|
if (iter == cfh_keys.end()) {
|
|
// key not yet seen, store it.
|
|
cfh_keys.insert({std::move(key_str)});
|
|
}
|
|
}
|
|
|
|
Status PutCF(uint32_t column_family_id, const Slice& key,
|
|
const Slice& /* unused */) override {
|
|
RecordKey(column_family_id, key);
|
|
return Status::OK();
|
|
}
|
|
Status MergeCF(uint32_t column_family_id, const Slice& key,
|
|
const Slice& /* unused */) override {
|
|
RecordKey(column_family_id, key);
|
|
return Status::OK();
|
|
}
|
|
Status DeleteCF(uint32_t column_family_id, const Slice& key) override {
|
|
RecordKey(column_family_id, key);
|
|
return Status::OK();
|
|
}
|
|
};
|
|
|
|
// Iterating on this handler will add all keys in this batch into keys
|
|
Handler handler;
|
|
Status s = batch->Iterate(&handler);
|
|
if (!s.ok()) {
|
|
return s;
|
|
}
|
|
|
|
// Attempt to lock all keys
|
|
for (const auto& cf_iter : handler.keys_) {
|
|
uint32_t cfh_id = cf_iter.first;
|
|
auto& cfh_keys = cf_iter.second;
|
|
|
|
for (const auto& key_iter : cfh_keys) {
|
|
const std::string& key = key_iter;
|
|
|
|
s = txn_db_impl_->TryLock(this, cfh_id, key, true /* exclusive */);
|
|
if (!s.ok()) {
|
|
break;
|
|
}
|
|
PointLockRequest r;
|
|
r.column_family_id = cfh_id;
|
|
r.key = key;
|
|
r.seq = kMaxSequenceNumber;
|
|
r.read_only = false;
|
|
r.exclusive = true;
|
|
keys_to_unlock->Track(r);
|
|
}
|
|
|
|
if (!s.ok()) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!s.ok()) {
|
|
txn_db_impl_->UnLock(this, *keys_to_unlock);
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
// Attempt to lock this key.
|
|
// Returns OK if the key has been successfully locked. Non-ok, otherwise.
|
|
// If check_shapshot is true and this transaction has a snapshot set,
|
|
// this key will only be locked if there have been no writes to this key since
|
|
// the snapshot time.
|
|
Status PessimisticTransaction::TryLock(ColumnFamilyHandle* column_family,
|
|
const Slice& key, bool read_only,
|
|
bool exclusive, const bool do_validate,
|
|
const bool assume_tracked) {
|
|
assert(!assume_tracked || !do_validate);
|
|
Status s;
|
|
if (UNLIKELY(skip_concurrency_control_)) {
|
|
return s;
|
|
}
|
|
uint32_t cfh_id = GetColumnFamilyID(column_family);
|
|
std::string key_str = key.ToString();
|
|
|
|
PointLockStatus status;
|
|
bool lock_upgrade;
|
|
bool previously_locked;
|
|
if (tracked_locks_->IsPointLockSupported()) {
|
|
status = tracked_locks_->GetPointLockStatus(cfh_id, key_str);
|
|
previously_locked = status.locked;
|
|
lock_upgrade = previously_locked && exclusive && !status.exclusive;
|
|
} else {
|
|
// If the record is tracked, we can assume it was locked, too.
|
|
previously_locked = assume_tracked;
|
|
status.locked = false;
|
|
lock_upgrade = false;
|
|
}
|
|
|
|
// Lock this key if this transactions hasn't already locked it or we require
|
|
// an upgrade.
|
|
if (!previously_locked || lock_upgrade) {
|
|
s = txn_db_impl_->TryLock(this, cfh_id, key_str, exclusive);
|
|
}
|
|
|
|
SetSnapshotIfNeeded();
|
|
|
|
// Even though we do not care about doing conflict checking for this write,
|
|
// we still need to take a lock to make sure we do not cause a conflict with
|
|
// some other write. However, we do not need to check if there have been
|
|
// any writes since this transaction's snapshot.
|
|
// TODO(agiardullo): could optimize by supporting shared txn locks in the
|
|
// future
|
|
SequenceNumber tracked_at_seq =
|
|
status.locked ? status.seq : kMaxSequenceNumber;
|
|
if (!do_validate || snapshot_ == nullptr) {
|
|
if (assume_tracked && !previously_locked &&
|
|
tracked_locks_->IsPointLockSupported()) {
|
|
s = Status::InvalidArgument(
|
|
"assume_tracked is set but it is not tracked yet");
|
|
}
|
|
// Need to remember the earliest sequence number that we know that this
|
|
// key has not been modified after. This is useful if this same
|
|
// transaction
|
|
// later tries to lock this key again.
|
|
if (tracked_at_seq == kMaxSequenceNumber) {
|
|
// Since we haven't checked a snapshot, we only know this key has not
|
|
// been modified since after we locked it.
|
|
// Note: when last_seq_same_as_publish_seq_==false this is less than the
|
|
// latest allocated seq but it is ok since i) this is just a heuristic
|
|
// used only as a hint to avoid actual check for conflicts, ii) this would
|
|
// cause a false positive only if the snapthot is taken right after the
|
|
// lock, which would be an unusual sequence.
|
|
tracked_at_seq = db_->GetLatestSequenceNumber();
|
|
}
|
|
} else {
|
|
// If a snapshot is set, we need to make sure the key hasn't been modified
|
|
// since the snapshot. This must be done after we locked the key.
|
|
// If we already have validated an earilier snapshot it must has been
|
|
// reflected in tracked_at_seq and ValidateSnapshot will return OK.
|
|
if (s.ok()) {
|
|
s = ValidateSnapshot(column_family, key, &tracked_at_seq);
|
|
|
|
if (!s.ok()) {
|
|
// Failed to validate key
|
|
// Unlock key we just locked
|
|
if (lock_upgrade) {
|
|
s = txn_db_impl_->TryLock(this, cfh_id, key_str,
|
|
false /* exclusive */);
|
|
assert(s.ok());
|
|
} else if (!previously_locked) {
|
|
txn_db_impl_->UnLock(this, cfh_id, key.ToString());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (s.ok()) {
|
|
// We must track all the locked keys so that we can unlock them later. If
|
|
// the key is already locked, this func will update some stats on the
|
|
// tracked key. It could also update the tracked_at_seq if it is lower
|
|
// than the existing tracked key seq. These stats are necessary for
|
|
// RollbackToSavePoint to determine whether a key can be safely removed
|
|
// from tracked_keys_. Removal can only be done if a key was only locked
|
|
// during the current savepoint.
|
|
//
|
|
// Recall that if assume_tracked is true, we assume that TrackKey has been
|
|
// called previously since the last savepoint, with the same exclusive
|
|
// setting, and at a lower sequence number, so skipping here should be
|
|
// safe.
|
|
if (!assume_tracked) {
|
|
TrackKey(cfh_id, key_str, tracked_at_seq, read_only, exclusive);
|
|
} else {
|
|
#ifndef NDEBUG
|
|
if (tracked_locks_->IsPointLockSupported()) {
|
|
PointLockStatus lock_status =
|
|
tracked_locks_->GetPointLockStatus(cfh_id, key_str);
|
|
assert(lock_status.locked);
|
|
assert(lock_status.seq <= tracked_at_seq);
|
|
assert(lock_status.exclusive == exclusive);
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
Status PessimisticTransaction::GetRangeLock(ColumnFamilyHandle* column_family,
|
|
const Endpoint& start_endp,
|
|
const Endpoint& end_endp) {
|
|
ColumnFamilyHandle* cfh =
|
|
column_family ? column_family : db_impl_->DefaultColumnFamily();
|
|
uint32_t cfh_id = GetColumnFamilyID(cfh);
|
|
|
|
Status s = txn_db_impl_->TryRangeLock(this, cfh_id, start_endp, end_endp);
|
|
|
|
if (s.ok()) {
|
|
RangeLockRequest req{cfh_id, start_endp, end_endp};
|
|
tracked_locks_->Track(req);
|
|
}
|
|
return s;
|
|
}
|
|
|
|
// Return OK() if this key has not been modified more recently than the
|
|
// transaction snapshot_.
|
|
// tracked_at_seq is the global seq at which we either locked the key or already
|
|
// have done ValidateSnapshot.
|
|
Status PessimisticTransaction::ValidateSnapshot(
|
|
ColumnFamilyHandle* column_family, const Slice& key,
|
|
SequenceNumber* tracked_at_seq) {
|
|
assert(snapshot_);
|
|
|
|
SequenceNumber snap_seq = snapshot_->GetSequenceNumber();
|
|
if (*tracked_at_seq <= snap_seq) {
|
|
// If the key has been previous validated (or locked) at a sequence number
|
|
// earlier than the current snapshot's sequence number, we already know it
|
|
// has not been modified aftter snap_seq either.
|
|
return Status::OK();
|
|
}
|
|
// Otherwise we have either
|
|
// 1: tracked_at_seq == kMaxSequenceNumber, i.e., first time tracking the key
|
|
// 2: snap_seq < tracked_at_seq: last time we lock the key was via
|
|
// do_validate=false which means we had skipped ValidateSnapshot. In both
|
|
// cases we should do ValidateSnapshot now.
|
|
|
|
*tracked_at_seq = snap_seq;
|
|
|
|
ColumnFamilyHandle* cfh =
|
|
column_family ? column_family : db_impl_->DefaultColumnFamily();
|
|
|
|
assert(cfh);
|
|
const Comparator* const ucmp = cfh->GetComparator();
|
|
assert(ucmp);
|
|
size_t ts_sz = ucmp->timestamp_size();
|
|
std::string ts_buf;
|
|
if (ts_sz > 0 && read_timestamp_ < kMaxTxnTimestamp) {
|
|
assert(ts_sz == sizeof(read_timestamp_));
|
|
PutFixed64(&ts_buf, read_timestamp_);
|
|
}
|
|
|
|
return TransactionUtil::CheckKeyForConflicts(
|
|
db_impl_, cfh, key.ToString(), snap_seq, ts_sz == 0 ? nullptr : &ts_buf,
|
|
false /* cache_only */);
|
|
}
|
|
|
|
bool PessimisticTransaction::TryStealingLocks() {
|
|
assert(IsExpired());
|
|
TransactionState expected = STARTED;
|
|
return std::atomic_compare_exchange_strong(&txn_state_, &expected,
|
|
LOCKS_STOLEN);
|
|
}
|
|
|
|
void PessimisticTransaction::UnlockGetForUpdate(
|
|
ColumnFamilyHandle* column_family, const Slice& key) {
|
|
txn_db_impl_->UnLock(this, GetColumnFamilyID(column_family), key.ToString());
|
|
}
|
|
|
|
Status PessimisticTransaction::SetName(const TransactionName& name) {
|
|
Status s;
|
|
if (txn_state_ == STARTED) {
|
|
if (name_.length()) {
|
|
s = Status::InvalidArgument("Transaction has already been named.");
|
|
} else if (txn_db_impl_->GetTransactionByName(name) != nullptr) {
|
|
s = Status::InvalidArgument("Transaction name must be unique.");
|
|
} else if (name.length() < 1 || name.length() > 512) {
|
|
s = Status::InvalidArgument(
|
|
"Transaction name length must be between 1 and 512 chars.");
|
|
} else {
|
|
name_ = name;
|
|
txn_db_impl_->RegisterTransaction(this);
|
|
}
|
|
} else {
|
|
s = Status::InvalidArgument("Transaction is beyond state for naming.");
|
|
}
|
|
return s;
|
|
}
|
|
|
|
} // namespace ROCKSDB_NAMESPACE
|
|
|
|
#endif // ROCKSDB_LITE
|