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/**
* Copyright (C) 2018 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kTransaction
#include "mongo/platform/basic.h"
#include "mongo/db/transaction_coordinator.h"
#include "mongo/db/transaction_coordinator_catalog.h"
#include "mongo/db/transaction_coordinator.h"
#include "mongo/util/log.h"
namespace mongo {
TransactionCoordinatorCatalog::TransactionCoordinatorCatalog() = default;
TransactionCoordinatorCatalog::~TransactionCoordinatorCatalog() = default;
std::shared_ptr<TransactionCoordinator> TransactionCoordinatorCatalog::create(LogicalSessionId lsid,
TxnNumber txnNumber) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
// Create a new map for the session if it does not exist
if (_coordinatorsBySession.find(lsid) == _coordinatorsBySession.end()) {
_coordinatorsBySession[lsid] = {};
}
// We should never try to insert a coordinator if one already exists for this session and txn
// number. Logic for avoiding this due to e.g. malformed commands should be handled external to
// the catalog.
invariant(_coordinatorsBySession[lsid].find(txnNumber) == _coordinatorsBySession[lsid].end(),
"Cannot insert a TransactionCoordinator into the TransactionCoordinatorCatalog with "
"the same session ID and transaction number as a previous coordinator");
auto newCoordinator = std::make_shared<TransactionCoordinator>();
_coordinatorsBySession[lsid][txnNumber] = newCoordinator;
return newCoordinator;
}
boost::optional<std::shared_ptr<TransactionCoordinator>> TransactionCoordinatorCatalog::get(
LogicalSessionId lsid, TxnNumber txnNumber) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
const auto& coordinatorsForSessionIter = _coordinatorsBySession.find(lsid);
if (coordinatorsForSessionIter == _coordinatorsBySession.end()) {
return boost::none;
}
const auto& coordinatorsForSession = coordinatorsForSessionIter->second;
const auto& coordinatorForTxnIter = coordinatorsForSession.find(txnNumber);
if (coordinatorForTxnIter == coordinatorsForSession.end()) {
return boost::none;
}
return coordinatorForTxnIter->second;
}
boost::optional<std::pair<TxnNumber, std::shared_ptr<TransactionCoordinator>>>
TransactionCoordinatorCatalog::getLatestOnSession(LogicalSessionId lsid) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
const auto& coordinatorsForSessionIter = _coordinatorsBySession.find(lsid);
if (coordinatorsForSessionIter == _coordinatorsBySession.end()) {
return boost::none;
}
const auto& coordinatorsForSession = coordinatorsForSessionIter->second;
const auto& lastCoordinatorOnSession = coordinatorsForSession.rbegin();
// Should never have empty map for a session. Entries for sessions with no transactions should
// be removed.
invariant(lastCoordinatorOnSession != coordinatorsForSession.rend());
return std::make_pair(lastCoordinatorOnSession->first, lastCoordinatorOnSession->second);
}
void TransactionCoordinatorCatalog::remove(LogicalSessionId lsid, TxnNumber txnNumber) {
using CoordinatorState = TransactionCoordinator::StateMachine::State;
stdx::lock_guard<stdx::mutex> lk(_mutex);
const auto& coordinatorsForSessionIter = _coordinatorsBySession.find(lsid);
if (coordinatorsForSessionIter != _coordinatorsBySession.end()) {
auto& coordinatorsForSession = coordinatorsForSessionIter->second;
const auto& coordinatorForTxnIter = coordinatorsForSession.find(txnNumber);
if (coordinatorForTxnIter != coordinatorsForSession.end()) {
auto coordinator = coordinatorForTxnIter->second;
// TODO (SERVER-36304/37021): Reenable the below invariant once transaction participants
// are able to send votes and once we validate the state of the coordinator when a new
// transaction comes in for an existing session. For now, we're not validating the state
// of the coordinator which means it is possible that starting a new transaction before
// waiting for the previous one's coordinator to reach state committed or aborted will
// corrupt the previous transaction.
// invariant(coordinator->state() == CoordinatorState::kCommitted ||
// coordinator->state() == CoordinatorState::kAborted);
coordinatorsForSession.erase(coordinatorForTxnIter);
if (coordinatorsForSession.size() == 0) {
_coordinatorsBySession.erase(coordinatorsForSessionIter);
}
}
}
}
} // namespace mongo
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