rocksdb/utilities/transactions/optimistic_transaction.cc
Maysam Yabandeh b878f93c70 Extend Transaction::GetForUpdate with do_validate (#4680)
Summary:
Transaction::GetForUpdate is extended with a do_validate parameter with default value of true. If false it skips validating the snapshot (if there is any) before doing the read. After the read it also returns the latest value (expects the ReadOptions::snapshot to be nullptr). This allows RocksDB applications to use GetForUpdate similarly to how InnoDB does. Similarly ::Merge, ::Put, ::Delete, and ::SingleDelete are extended with assume_exclusive_tracked with default value of false. It true it indicates that call is assumed to be after a ::GetForUpdate(do_validate=false).
The Java APIs are accordingly updated.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4680

Differential Revision: D13068508

Pulled By: maysamyabandeh

fbshipit-source-id: f0b59db28f7f6a078b60844d902057140765e67d
2018-12-06 17:49:00 -08:00

135 lines
4.2 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/optimistic_transaction.h"
#include <string>
#include "db/column_family.h"
#include "db/db_impl.h"
#include "rocksdb/comparator.h"
#include "rocksdb/db.h"
#include "rocksdb/status.h"
#include "rocksdb/utilities/optimistic_transaction_db.h"
#include "util/cast_util.h"
#include "util/string_util.h"
#include "utilities/transactions/transaction_util.h"
namespace rocksdb {
struct WriteOptions;
OptimisticTransaction::OptimisticTransaction(
OptimisticTransactionDB* txn_db, const WriteOptions& write_options,
const OptimisticTransactionOptions& txn_options)
: TransactionBaseImpl(txn_db->GetBaseDB(), write_options), txn_db_(txn_db) {
Initialize(txn_options);
}
void OptimisticTransaction::Initialize(
const OptimisticTransactionOptions& txn_options) {
if (txn_options.set_snapshot) {
SetSnapshot();
}
}
void OptimisticTransaction::Reinitialize(
OptimisticTransactionDB* txn_db, const WriteOptions& write_options,
const OptimisticTransactionOptions& txn_options) {
TransactionBaseImpl::Reinitialize(txn_db->GetBaseDB(), write_options);
Initialize(txn_options);
}
OptimisticTransaction::~OptimisticTransaction() {}
void OptimisticTransaction::Clear() { TransactionBaseImpl::Clear(); }
Status OptimisticTransaction::Prepare() {
return Status::InvalidArgument(
"Two phase commit not supported for optimistic transactions.");
}
Status OptimisticTransaction::Commit() {
// Set up callback which will call CheckTransactionForConflicts() to
// check whether this transaction is safe to be committed.
OptimisticTransactionCallback callback(this);
DBImpl* db_impl = static_cast_with_check<DBImpl, DB>(db_->GetRootDB());
Status s = db_impl->WriteWithCallback(
write_options_, GetWriteBatch()->GetWriteBatch(), &callback);
if (s.ok()) {
Clear();
}
return s;
}
Status OptimisticTransaction::Rollback() {
Clear();
return Status::OK();
}
// Record this key so that we can check it for conflicts at commit time.
//
// 'exclusive' is unused for OptimisticTransaction.
Status OptimisticTransaction::TryLock(ColumnFamilyHandle* column_family,
const Slice& key, bool read_only,
bool exclusive, const bool do_validate,
const bool assume_tracked) {
assert(!assume_tracked); // not supported
(void)assume_tracked;
if (!do_validate) {
return Status::OK();
}
uint32_t cfh_id = GetColumnFamilyID(column_family);
SetSnapshotIfNeeded();
SequenceNumber seq;
if (snapshot_) {
seq = snapshot_->GetSequenceNumber();
} else {
seq = db_->GetLatestSequenceNumber();
}
std::string key_str = key.ToString();
TrackKey(cfh_id, key_str, seq, read_only, exclusive);
// Always return OK. Confilct checking will happen at commit time.
return Status::OK();
}
// Returns OK if it is safe to commit this transaction. Returns Status::Busy
// if there are read or write conflicts that would prevent us from committing OR
// if we can not determine whether there would be any such conflicts.
//
// Should only be called on writer thread in order to avoid any race conditions
// in detecting write conflicts.
Status OptimisticTransaction::CheckTransactionForConflicts(DB* db) {
Status result;
auto db_impl = static_cast_with_check<DBImpl, DB>(db);
// Since we are on the write thread and do not want to block other writers,
// we will do a cache-only conflict check. This can result in TryAgain
// getting returned if there is not sufficient memtable history to check
// for conflicts.
return TransactionUtil::CheckKeysForConflicts(db_impl, GetTrackedKeys(),
true /* cache_only */);
}
Status OptimisticTransaction::SetName(const TransactionName& /* unused */) {
return Status::InvalidArgument("Optimistic transactions cannot be named.");
}
} // namespace rocksdb
#endif // ROCKSDB_LITE