mirror of https://github.com/facebook/rocksdb.git
125 lines
3.7 KiB
C++
125 lines
3.7 KiB
C++
// Copyright (c) 2015, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#ifndef ROCKSDB_LITE
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#include "utilities/transactions/optimistic_transaction_impl.h"
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#include <algorithm>
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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.h"
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#include "rocksdb/comparator.h"
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#include "rocksdb/db.h"
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#include "rocksdb/status.h"
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#include "rocksdb/utilities/optimistic_transaction_db.h"
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#include "util/string_util.h"
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#include "utilities/transactions/transaction_util.h"
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namespace rocksdb {
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struct WriteOptions;
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OptimisticTransactionImpl::OptimisticTransactionImpl(
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OptimisticTransactionDB* txn_db, const WriteOptions& write_options,
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const OptimisticTransactionOptions& txn_options)
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: TransactionBaseImpl(txn_db->GetBaseDB(), write_options), txn_db_(txn_db) {
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if (txn_options.set_snapshot) {
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SetSnapshot();
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}
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}
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OptimisticTransactionImpl::~OptimisticTransactionImpl() {
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}
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void OptimisticTransactionImpl::Cleanup() {
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tracked_keys_.clear();
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save_points_.reset(nullptr);
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write_batch_->Clear();
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}
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Status OptimisticTransactionImpl::Commit() {
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// Set up callback which will call CheckTransactionForConflicts() to
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// check whether this transaction is safe to be committed.
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OptimisticTransactionCallback callback(this);
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DBImpl* db_impl = dynamic_cast<DBImpl*>(db_->GetRootDB());
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if (db_impl == nullptr) {
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// This should only happen if we support creating transactions from
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// a StackableDB and someone overrides GetRootDB().
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return Status::InvalidArgument(
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"DB::GetRootDB() returned an unexpected DB class");
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}
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Status s = db_impl->WriteWithCallback(
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write_options_, write_batch_->GetWriteBatch(), &callback);
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if (s.ok()) {
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Cleanup();
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}
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return s;
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}
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void OptimisticTransactionImpl::Rollback() {
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Cleanup();
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}
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// Record this key so that we can check it for conflicts at commit time.
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Status OptimisticTransactionImpl::TryLock(ColumnFamilyHandle* column_family,
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const Slice& key, bool untracked) {
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if (untracked) {
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return Status::OK();
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}
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uint32_t cfh_id = GetColumnFamilyID(column_family);
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SequenceNumber seq;
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if (snapshot_) {
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seq = snapshot_->snapshot()->GetSequenceNumber();
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} else {
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seq = db_->GetLatestSequenceNumber();
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}
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std::string key_str = key.ToString();
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auto iter = tracked_keys_[cfh_id].find(key_str);
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if (iter == tracked_keys_[cfh_id].end()) {
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// key not yet seen, store it.
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tracked_keys_[cfh_id].insert({std::move(key_str), seq});
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} else {
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SequenceNumber old_seq = iter->second;
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if (seq < old_seq) {
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// Snapshot has changed since we last saw this key, need to
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// store the earliest seen sequence number.
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tracked_keys_[cfh_id][key_str] = seq;
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}
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}
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// Always return OK. Confilct checking will happen at commit time.
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return Status::OK();
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}
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// Returns OK if it is safe to commit this transaction. Returns Status::Busy
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// if there are read or write conflicts that would prevent us from committing OR
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// if we can not determine whether there would be any such conflicts.
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//
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// Should only be called on writer thread in order to avoid any race conditions
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// in detecting
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// write conflicts.
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Status OptimisticTransactionImpl::CheckTransactionForConflicts(DB* db) {
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Status result;
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assert(dynamic_cast<DBImpl*>(db) != nullptr);
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auto db_impl = reinterpret_cast<DBImpl*>(db);
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return TransactionUtil::CheckKeysForConflicts(db_impl, &tracked_keys_);
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}
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} // namespace rocksdb
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#endif // ROCKSDB_LITE
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