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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/optimistic_transaction.h"
#include <string>
#include "db/column_family.h"
#include "db/db_impl/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"
#include "utilities/transactions/optimistic_transaction.h"
#include "utilities/transactions/optimistic_transaction_db_impl.h"
namespace ROCKSDB_NAMESPACE {
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() {
auto txn_db_impl = static_cast_with_check<OptimisticTransactionDBImpl,
OptimisticTransactionDB>(txn_db_);
assert(txn_db_impl);
switch (txn_db_impl->GetValidatePolicy()) {
case OccValidationPolicy::kValidateParallel:
return CommitWithParallelValidate();
case OccValidationPolicy::kValidateSerial:
return CommitWithSerialValidate();
default:
assert(0);
}
// unreachable, just void compiler complain
return Status::OK();
}
Status OptimisticTransaction::CommitWithSerialValidate() {
// 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::CommitWithParallelValidate() {
auto txn_db_impl = static_cast_with_check<OptimisticTransactionDBImpl,
OptimisticTransactionDB>(txn_db_);
assert(txn_db_impl);
DBImpl* db_impl = static_cast_with_check<DBImpl, DB>(db_->GetRootDB());
assert(db_impl);
const size_t space = txn_db_impl->GetLockBucketsSize();
std::set<size_t> lk_idxes;
std::vector<std::unique_lock<std::mutex>> lks;
for (auto& cfit : GetTrackedKeys()) {
for (auto& keyit : cfit.second) {
lk_idxes.insert(fastrange64(GetSliceNPHash64(keyit.first), space));
}
}
// NOTE: in a single txn, all bucket-locks are taken in ascending order.
// In this way, txns from different threads all obey this rule so that
// deadlock can be avoided.
for (auto v : lk_idxes) {
lks.emplace_back(txn_db_impl->LockBucket(v));
}
Status s = TransactionUtil::CheckKeysForConflicts(db_impl, GetTrackedKeys(),
true /* cache_only */);
if (!s.ok()) {
return s;
}
s = db_impl->Write(write_options_, GetWriteBatch()->GetWriteBatch());
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_NAMESPACE
#endif // ROCKSDB_LITE
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