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transaction_participant.cpp
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transaction_participant.cpp
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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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 LOGV2_FOR_TRANSACTION(ID, DLEVEL, MESSAGE, ...) \
LOGV2_DEBUG_OPTIONS(ID, DLEVEL, {logv2::LogComponent::kTransaction}, MESSAGE, ##__VA_ARGS__)
#include "mongo/db/transaction/transaction_participant.h"
#include <absl/container/node_hash_map.h>
#include <absl/container/node_hash_set.h>
#include <absl/meta/type_traits.h>
#include <algorithm>
#include <boost/cstdint.hpp>
#include <boost/none.hpp>
#include <boost/optional.hpp>
#include <boost/smart_ptr.hpp>
#include <boost/smart_ptr/intrusive_ptr.hpp>
#include <cstddef>
#include <exception>
#include <fmt/format.h>
#include <fstream> // IWYU pragma: keep
#include <future>
#include <type_traits>
#include <boost/move/utility_core.hpp>
#include <boost/optional/optional.hpp>
#include <boost/preprocessor/control/iif.hpp>
#include "mongo/base/status.h"
#include "mongo/base/status_with.h"
#include "mongo/bson/bsonelement.h"
#include "mongo/bson/bsonmisc.h"
#include "mongo/bson/util/builder.h"
#include "mongo/client/dbclient_cursor.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/collection_catalog.h"
#include "mongo/db/catalog/collection_write_path.h"
#include "mongo/db/catalog/database_holder.h"
#include "mongo/db/catalog/index_catalog.h"
#include "mongo/db/catalog/index_catalog_entry.h"
#include "mongo/db/catalog/local_oplog_info.h"
#include "mongo/db/catalog/uncommitted_catalog_updates.h"
#include "mongo/db/catalog_raii.h"
#include "mongo/db/cluster_role.h"
#include "mongo/db/commands/test_commands_enabled.h"
#include "mongo/db/concurrency/d_concurrency.h"
#include "mongo/db/concurrency/exception_util.h"
#include "mongo/db/concurrency/lock_manager_defs.h"
#include "mongo/db/concurrency/locker_impl.h"
#include "mongo/db/concurrency/replication_state_transition_lock_guard.h"
#include "mongo/db/curop.h"
#include "mongo/db/curop_failpoint_helpers.h"
#include "mongo/db/database_name.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/index/index_access_method.h"
#include "mongo/db/logical_time.h"
#include "mongo/db/matcher/expression.h"
#include "mongo/db/matcher/expression_parser.h"
#include "mongo/db/op_observer/op_observer.h"
#include "mongo/db/ops/write_ops_parsers.h"
#include "mongo/db/ops/write_ops_retryability.h"
#include "mongo/db/pipeline/expression_context.h"
#include "mongo/db/query/collation/collator_interface.h"
#include "mongo/db/query/find_command.h"
#include "mongo/db/record_id.h"
#include "mongo/db/repl/apply_ops_command_info.h"
#include "mongo/db/repl/oplog_entry_gen.h"
#include "mongo/db/repl/read_concern_level.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/db/repl/storage_interface.h"
#include "mongo/db/s/sharding_write_router.h"
#include "mongo/db/server_options.h"
#include "mongo/db/service_context.h"
#include "mongo/db/session/internal_session_pool.h"
#include "mongo/db/session/logical_session_id.h"
#include "mongo/db/session/logical_session_id_helpers.h"
#include "mongo/db/session/session_catalog_mongod.h"
#include "mongo/db/shard_role.h"
#include "mongo/db/stats/fill_locker_info.h"
#include "mongo/db/stats/resource_consumption_metrics.h"
#include "mongo/db/stats/top.h"
#include "mongo/db/storage/record_data.h"
#include "mongo/db/storage/record_store.h"
#include "mongo/db/storage/snapshot.h"
#include "mongo/db/storage/storage_stats.h"
#include "mongo/db/transaction/retryable_writes_stats.h"
#include "mongo/db/transaction/server_transactions_metrics.h"
#include "mongo/db/transaction/transaction_history_iterator.h"
#include "mongo/db/transaction/transaction_participant_gen.h"
#include "mongo/db/transaction_resources.h"
#include "mongo/db/txn_retry_counter_too_old_info.h"
#include "mongo/db/vector_clock_mutable.h"
#include "mongo/db/write_concern_options.h"
#include "mongo/idl/idl_parser.h"
#include "mongo/logv2/log.h"
#include "mongo/logv2/log_attr.h"
#include "mongo/logv2/log_component.h"
#include "mongo/platform/atomic_word.h"
#include "mongo/platform/compiler.h"
#include "mongo/s/database_version.h"
#include "mongo/s/shard_version.h"
#include "mongo/s/would_change_owning_shard_exception.h"
#include "mongo/transport/session.h"
#include "mongo/util/clock_source.h"
#include "mongo/util/concurrency/admission_context.h"
#include "mongo/util/decorable.h"
#include "mongo/util/duration.h"
#include "mongo/util/fail_point.h"
#include "mongo/util/intrusive_counter.h"
#include "mongo/util/log_with_sampling.h"
#include "mongo/util/net/socket_utils.h"
#include "mongo/util/scopeguard.h"
#include "mongo/util/str.h"
#include "mongo/util/string_map.h"
#include "mongo/util/tick_source.h"
#include "mongo/util/uuid.h"
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kStorage
namespace mongo {
using namespace fmt::literals;
namespace {
// Failpoint which will pause an operation just after allocating a point-in-time storage engine
// transaction.
MONGO_FAIL_POINT_DEFINE(hangAfterPreallocateSnapshot);
MONGO_FAIL_POINT_DEFINE(hangAfterReservingPrepareTimestamp);
MONGO_FAIL_POINT_DEFINE(hangAfterSettingPrepareStartTime);
MONGO_FAIL_POINT_DEFINE(hangBeforeReleasingTransactionOplogHole);
MONGO_FAIL_POINT_DEFINE(skipCommitTxnCheckPrepareMajorityCommitted);
MONGO_FAIL_POINT_DEFINE(restoreLocksFail);
MONGO_FAIL_POINT_DEFINE(failTransactionNoopWrite);
MONGO_FAIL_POINT_DEFINE(hangInCommitSplitPreparedTxnOnPrimary);
const auto getTransactionParticipant = Session::declareDecoration<TransactionParticipant>();
const auto retryableWriteTransactionParticipantCatalogDecoration =
Session::declareDecoration<RetryableWriteTransactionParticipantCatalog>();
/**
* Returns the RetryableWriteTransactionParticipantCatalog for the given session.
*/
RetryableWriteTransactionParticipantCatalog& getRetryableWriteTransactionParticipantCatalog(
Session* session) {
if (const auto parentSession = session->getParentSession()) {
return retryableWriteTransactionParticipantCatalogDecoration(parentSession);
}
return retryableWriteTransactionParticipantCatalogDecoration(session);
}
/**
* Returns the RetryableWriteTransactionParticipantCatalog for the session checked out by the
* given 'opCtx'.
*/
RetryableWriteTransactionParticipantCatalog& getRetryableWriteTransactionParticipantCatalog(
OperationContext* opCtx) {
auto session = OperationContextSession::get(opCtx);
return getRetryableWriteTransactionParticipantCatalog(session);
}
// The command names that are allowed in a prepared transaction.
const StringMap<int> preparedTxnCmdAllowlist = {
{"abortTransaction", 1}, {"commitTransaction", 1}, {"prepareTransaction", 1}};
void fassertOnRepeatedExecution(const LogicalSessionId& lsid,
TxnNumberAndRetryCounter txnNumberAndRetryCounter,
StmtId stmtId,
const repl::OpTime& firstOpTime,
const repl::OpTime& secondOpTime) {
LOGV2_FATAL(
40526,
"Statement id {stmtId} from transaction [ {lsid}:{txnNumberAndRetryCounter} ] was "
"committed once with opTime {firstCommitOpTime} and a second time with opTime { "
"secondCommitOpTime}. This indicates possible data corruption or server bug and the "
"process will be terminated.",
"Statement from transaction was committed twice. This indicates possible data corruption "
"or server bug and the process will be terminated",
"stmtId"_attr = stmtId,
"lsid"_attr = lsid.toBSON(),
"txnNumberAndRetryCounter"_attr = txnNumberAndRetryCounter,
"firstCommitOpTime"_attr = firstOpTime,
"secondCommitOpTime"_attr = secondOpTime);
}
void validateTransactionHistoryApplyOpsOplogEntry(const repl::OplogEntry& oplogEntry) {
uassert(5875601,
"Found an applyOps oplog entry for retryable writes that were executed without "
"using a retryable internal transaction",
isInternalSessionForRetryableWrite(*oplogEntry.getSessionId()));
uassert(5875602,
"Found an applyOps oplog entry for retryable internal transaction with top-level "
"'stmtId' field",
oplogEntry.getStatementIds().empty());
}
/**
* Runs the given 'callable' with a DBDirectClient with a no-timestamp read source, and restores
* the original timestamp read source after returning. Used for performing a read against the
* config.transactions collection during refresh below since snapshot reads and causal consistent
* majority reads against are not supported in that collection.
*/
template <typename Callable>
auto performReadWithNoTimestampDBDirectClient(OperationContext* opCtx, Callable&& callable) {
ReadSourceScope readSourceScope(opCtx, RecoveryUnit::ReadSource::kNoTimestamp);
// ReadConcern must also be fixed for the new scope. It will get restored when exiting this.
auto originalReadConcern =
std::exchange(repl::ReadConcernArgs::get(opCtx), repl::ReadConcernArgs());
ON_BLOCK_EXIT([&] { repl::ReadConcernArgs::get(opCtx) = std::move(originalReadConcern); });
DBDirectClient client(opCtx);
return callable(&client);
}
void rethrowPartialIndexQueryBadValueWithContext(const DBException& ex) {
if (ex.reason().find("hint provided does not correspond to an existing index") !=
std::string::npos) {
uassertStatusOKWithContext(
ex.toStatus(),
str::stream()
<< "Failed to find partial index for "
<< NamespaceString::kSessionTransactionsTableNamespace.toStringForErrorMsg()
<< ". Please create an index directly on this replica set with the specification: "
<< MongoDSessionCatalog::getConfigTxnPartialIndexSpec() << " or drop the "
<< NamespaceString::kSessionTransactionsTableNamespace.toStringForErrorMsg()
<< " collection and step up a new primary.");
}
}
struct ActiveTransactionHistory {
boost::optional<SessionTxnRecord> lastTxnRecord;
TransactionParticipant::CommittedStatementTimestampMap committedStatements;
bool hasIncompleteHistory{false};
};
ActiveTransactionHistory fetchActiveTransactionHistory(OperationContext* opCtx,
const LogicalSessionId& lsid,
bool fetchOplogEntries) {
// Storage engine operations require at a least global MODE_IS lock. In multi-document
// transactions, storage opeartions require at least a global MODE_IX lock. Prevent lock
// upgrading in the case of a multi-document transaction.
Lock::GlobalLock lk(opCtx, opCtx->inMultiDocumentTransaction() ? MODE_IX : MODE_IS);
ActiveTransactionHistory result;
result.lastTxnRecord = [&]() -> boost::optional<SessionTxnRecord> {
ReadSourceScope readSourceScope(opCtx, RecoveryUnit::ReadSource::kNoTimestamp);
auto originalReadConcern =
std::exchange(repl::ReadConcernArgs::get(opCtx), repl::ReadConcernArgs());
ON_BLOCK_EXIT([&] { repl::ReadConcernArgs::get(opCtx) = std::move(originalReadConcern); });
AutoGetCollectionForRead autoRead(opCtx,
NamespaceString::kSessionTransactionsTableNamespace);
BSONObjBuilder bob;
bob.append("_id", lsid.toBSON());
auto id = bob.obj();
BSONElement elementKey = id.firstElement();
auto storageInterface = repl::StorageInterface::get(opCtx);
auto swObj = storageInterface->findById(
opCtx, NamespaceString::kSessionTransactionsTableNamespace, elementKey);
if (!swObj.isOK()) {
if (swObj.getStatus() == ErrorCodes::NoSuchKey ||
swObj.getStatus() == ErrorCodes::NamespaceNotFound) {
return boost::none;
}
uassertStatusOK(swObj.getStatus());
}
return SessionTxnRecord::parse(IDLParserContext("parse latest txn record for session"),
swObj.getValue());
}();
if (!result.lastTxnRecord) {
return result;
}
if (auto state = result.lastTxnRecord->getState()) {
if (!isInternalSessionForRetryableWrite(lsid) || state != DurableTxnStateEnum::kCommitted) {
// When state is given, it must be a transaction, so we don't need to traverse the
// history if it is not a committed transaction for retryable writes.
return result;
}
}
if (!fetchOplogEntries) {
return result;
}
// Helper for registering statement ids of an oplog entry for a retryable write or a retryable
// internal transaction.
auto insertStmtIdsForOplogEntry = [&](const repl::OplogEntry& entry) {
for (auto stmtId : entry.getStatementIds()) {
uassert(5875604,
str::stream() << "Found an oplog entry with an invalid stmtId "
<< entry.toBSONForLogging(),
stmtId >= 0);
const auto insertRes = result.committedStatements.emplace(stmtId, entry.getOpTime());
if (!insertRes.second) {
const auto& existingOpTime = insertRes.first->second;
fassertOnRepeatedExecution(lsid,
result.lastTxnRecord->getTxnNum(),
stmtId,
existingOpTime,
entry.getOpTime());
}
}
};
// Restore the current timestamp read source after fetching transaction history, which may
// change our ReadSource.
ReadSourceScope readSourceScope(opCtx, RecoveryUnit::ReadSource::kNoTimestamp);
auto originalReadConcern =
std::exchange(repl::ReadConcernArgs::get(opCtx), repl::ReadConcernArgs());
ON_BLOCK_EXIT([&] { repl::ReadConcernArgs::get(opCtx) = std::move(originalReadConcern); });
auto it = TransactionHistoryIterator(result.lastTxnRecord->getLastWriteOpTime());
while (it.hasNext()) {
try {
const auto entry = it.next(opCtx);
auto stmtIds = entry.getStatementIds();
if (isInternalSessionForRetryableWrite(lsid)) {
uassert(5875605,
"Found an oplog entry for retryable internal transaction with top-level "
"'stmtId' field",
stmtIds.empty());
if (entry.getCommandType() == repl::OplogEntry::CommandType::kCommitTransaction) {
continue;
} else if (entry.getCommandType() == repl::OplogEntry::CommandType::kApplyOps) {
validateTransactionHistoryApplyOpsOplogEntry(entry);
std::vector<repl::OplogEntry> innerEntries;
repl::ApplyOps::extractOperationsTo(
entry, entry.getEntry().toBSON(), &innerEntries);
for (const auto& innerEntry : innerEntries) {
insertStmtIdsForOplogEntry(innerEntry);
}
} else {
MONGO_UNREACHABLE;
}
} else {
// Oplog entries for retryable writes are expected to have a statement id.
invariant(!stmtIds.empty());
if (stmtIds.front() == kIncompleteHistoryStmtId) {
// Only the dead end sentinel can have this id for oplog write history
invariant(stmtIds.size() == 1);
invariant(entry.getObject2());
invariant(entry.getObject2()->woCompare(
TransactionParticipant::kDeadEndSentinel) == 0);
result.hasIncompleteHistory = true;
continue;
}
insertStmtIdsForOplogEntry(entry);
}
} catch (const DBException& ex) {
if (ex.code() == ErrorCodes::IncompleteTransactionHistory) {
result.hasIncompleteHistory = true;
break;
}
throw;
}
}
return result;
}
/**
* Returns the highest txnNumber in the given session that has corresponding internal sessions as
* found in the config.transactions collection.
*/
TxnNumber fetchHighestTxnNumberWithInternalSessions(OperationContext* opCtx,
const LogicalSessionId& parentLsid) {
TxnNumber highestTxnNumber = kUninitializedTxnNumber;
try {
performReadWithNoTimestampDBDirectClient(opCtx, [&](DBDirectClient* client) {
FindCommandRequest findRequest{NamespaceString::kSessionTransactionsTableNamespace};
findRequest.setFilter(
BSON(SessionTxnRecord::kParentSessionIdFieldName << parentLsid.toBSON()));
findRequest.setSort(BSON((SessionTxnRecord::kSessionIdFieldName + "." +
LogicalSessionId::kTxnNumberFieldName)
<< -1));
findRequest.setProjection(BSON(SessionTxnRecord::kSessionIdFieldName << 1));
findRequest.setLimit(1);
findRequest.setHint(BSON("$hint" << MongoDSessionCatalog::kConfigTxnsPartialIndexName));
auto cursor = client->find(findRequest);
while (cursor->more()) {
const auto doc = cursor->next();
const auto childLsid = LogicalSessionId::parse(IDLParserContext("LogicalSessionId"),
doc.getObjectField("_id"));
invariant(!cursor->more());
// All config.transactions entries with the parentLsid field should have a txnNumber
// in their sessionId, but users may manually modify that collection so we can't
// assume that.
if (childLsid.getTxnNumber().has_value()) {
highestTxnNumber = *childLsid.getTxnNumber();
}
}
});
} catch (const ExceptionFor<ErrorCodes::BadValue>& ex) {
rethrowPartialIndexQueryBadValueWithContext(ex);
throw;
}
return highestTxnNumber;
}
void updateSessionEntry(OperationContext* opCtx,
const UpdateRequest& updateRequest,
const LogicalSessionId& sessionId,
TxnNumber txnNum) {
// Current code only supports replacement update.
dassert(updateRequest.getUpdateModification().type() ==
write_ops::UpdateModification::Type::kReplacement);
const auto updateMod = updateRequest.getUpdateModification().getUpdateReplacement();
// TODO SERVER-58243: evaluate whether this is safe or whether acquiring the lock can block.
AllowLockAcquisitionOnTimestampedUnitOfWork allowLockAcquisition(opCtx->lockState());
const auto collection = acquireCollection(
opCtx,
CollectionAcquisitionRequest(NamespaceString::kSessionTransactionsTableNamespace,
PlacementConcern{boost::none, ShardVersion::UNSHARDED()},
repl::ReadConcernArgs::get(opCtx),
AcquisitionPrerequisites::kWrite),
MODE_IX);
uassert(
40527,
str::stream() << "Unable to persist transaction state because the session transaction "
"collection is missing. This indicates that the "
<< NamespaceString::kSessionTransactionsTableNamespace.toStringForErrorMsg()
<< " collection has been manually deleted.",
collection.exists());
WriteUnitOfWork wuow(opCtx);
auto idIndex = collection.getCollectionPtr()->getIndexCatalog()->findIdIndex(opCtx);
uassert(
40672,
str::stream() << "Failed to fetch _id index for "
<< NamespaceString::kSessionTransactionsTableNamespace.toStringForErrorMsg(),
idIndex);
const IndexCatalogEntry* entry =
collection.getCollectionPtr()->getIndexCatalog()->getEntry(idIndex);
auto indexAccess = entry->accessMethod()->asSortedData();
// Since we are looking up a key inside the _id index, create a key object consisting of only
// the _id field.
auto idToFetch = updateRequest.getQuery().firstElement();
auto toUpdateIdDoc = idToFetch.wrap();
dassert(idToFetch.fieldNameStringData() == "_id"_sd);
auto recordId =
indexAccess->findSingle(opCtx, collection.getCollectionPtr(), entry, toUpdateIdDoc);
auto startingSnapshotId = opCtx->recoveryUnit()->getSnapshotId();
if (recordId.isNull()) {
// Upsert case.
auto status = collection_internal::insertDocument(
opCtx, collection.getCollectionPtr(), InsertStatement(updateMod), nullptr, false);
if (status == ErrorCodes::DuplicateKey) {
throwWriteConflictException(
str::stream() << "Updating session entry failed with duplicate key, session "_sd
<< sessionId << ", transaction "_sd << txnNum);
}
uassertStatusOK(status);
wuow.commit();
return;
}
auto originalRecordData =
collection.getCollectionPtr()->getRecordStore()->dataFor(opCtx, recordId);
auto originalDoc = originalRecordData.toBson();
const auto parentLsidFieldName = SessionTxnRecord::kParentSessionIdFieldName;
uassert(
5875700,
str::stream() << "Cannot modify the '" << parentLsidFieldName << "' field of "
<< NamespaceString::kSessionTransactionsTableNamespace.toStringForErrorMsg()
<< " entries",
updateMod.getObjectField(parentLsidFieldName)
.woCompare(originalDoc.getObjectField(parentLsidFieldName)) == 0);
invariant(collection.getCollectionPtr()->getDefaultCollator() == nullptr);
boost::intrusive_ptr<ExpressionContext> expCtx(
new ExpressionContext(opCtx, nullptr, updateRequest.getNamespaceString()));
auto matcher =
fassert(40673, MatchExpressionParser::parse(updateRequest.getQuery(), std::move(expCtx)));
if (!matcher->matchesBSON(originalDoc)) {
// Document no longer match what we expect so throw WCE to make the caller re-examine.
throwWriteConflictException(
str::stream() << "Updating session entry failed as document no longer matches, "_sd
<< "session "_sd << sessionId << ", transaction "_sd << txnNum);
}
CollectionUpdateArgs args{originalDoc};
args.criteria = toUpdateIdDoc;
args.update = updateMod;
// Specify kUpdateNoIndexes because the sessions collection has two indexes: {_id: 1} and
// {parentLsid: 1, _id.txnNumber: 1, _id: 1}, and none of the fields are mutable.
collection_internal::updateDocument(opCtx,
collection.getCollectionPtr(),
recordId,
Snapshotted<BSONObj>(startingSnapshotId, originalDoc),
updateMod,
collection_internal::kUpdateNoIndexes,
nullptr /* indexesAffected */,
nullptr /* opDebug */,
&args);
wuow.commit();
}
// Failpoint which allows different failure actions to happen after each write. Supports the
// parameters below, which can be combined with each other (unless explicitly disallowed):
//
// closeConnection (bool, default = true): Closes the connection on which the write was executed.
// failBeforeCommitExceptionCode (int, default = not specified): If set, the specified exception
// code will be thrown, which will cause the write to not commit; if not specified, the write
// will be allowed to commit.
MONGO_FAIL_POINT_DEFINE(onPrimaryTransactionalWrite);
} // namespace
const BSONObj TransactionParticipant::kDeadEndSentinel(BSON("$incompleteOplogHistory" << 1));
TransactionParticipant::TransactionParticipant() = default;
TransactionParticipant::~TransactionParticipant() {
// invariant(!_o.txnState.isInProgress());
}
TransactionParticipant::Observer::Observer(const ObservableSession& osession)
: Observer(&getTransactionParticipant(osession.get())) {}
TransactionParticipant::Participant::Participant(OperationContext* opCtx)
: Observer([opCtx]() -> TransactionParticipant* {
if (auto session = OperationContextSession::get(opCtx)) {
return &getTransactionParticipant(session);
}
return nullptr;
}()) {}
TransactionParticipant::Participant::Participant(OperationContext* opCtx, Session* session)
: Observer([opCtx, session]() -> TransactionParticipant* {
invariant(session);
auto checkedOutSession = OperationContextSession::get(opCtx);
uassert(6202000,
str::stream() << "Cannot get the transaction participant for the session "
<< session->getSessionId()
<< " without having it or its parent checked out",
checkedOutSession &&
(castToParentSessionId(checkedOutSession->getSessionId()) ==
castToParentSessionId(session->getSessionId())));
return &getTransactionParticipant(session);
}()) {}
TransactionParticipant::Participant::Participant(const SessionToKill& session)
: Observer(&getTransactionParticipant(session.get())) {}
void TransactionParticipant::performNoopWrite(OperationContext* opCtx, StringData msg) {
const auto replCoord = repl::ReplicationCoordinator::get(opCtx);
// The locker must not have a max lock timeout when this noop write is performed, since if it
// threw LockTimeout, this would be treated as a TransientTransactionError, which would indicate
// it's safe to retry the entire transaction. We cannot know it is safe to attach
// TransientTransactionError until the noop write has been performed and the writeConcern has
// been satisfied.
invariant(!opCtx->lockState()->hasMaxLockTimeout());
// Simulate an operation timeout and fail the noop write if the fail point is enabled. This is
// to test that NoSuchTransaction error is not considered transient if the noop write cannot
// occur.
if (MONGO_unlikely(failTransactionNoopWrite.shouldFail())) {
uasserted(ErrorCodes::MaxTimeMSExpired, "failTransactionNoopWrite fail point enabled");
}
{
AutoGetOplog oplogWrite(opCtx, OplogAccessMode::kWrite);
uassert(ErrorCodes::NotWritablePrimary,
"Not primary when performing noop write for {}"_format(msg),
replCoord->canAcceptWritesForDatabase(opCtx, DatabaseName::kAdmin));
writeConflictRetry(
opCtx, "performNoopWrite", NamespaceString::kRsOplogNamespace, [&opCtx, &msg] {
WriteUnitOfWork wuow(opCtx);
opCtx->getClient()->getServiceContext()->getOpObserver()->onOpMessage(
opCtx, BSON("msg" << msg));
wuow.commit();
});
}
}
StorageEngine::OldestActiveTransactionTimestampResult
TransactionParticipant::getOldestActiveTimestamp(Timestamp stableTimestamp) {
// Read from config.transactions at the stable timestamp for the oldest active transaction
// timestamp. Use a short timeout: another thread might have the global lock e.g. to shut down
// the server, and it both blocks this thread from querying config.transactions and waits for
// this thread to terminate.
auto client = getGlobalServiceContext()->makeClient("OldestActiveTxnTimestamp");
// TODO(SERVER-74656): Please revisit if this thread could be made killable.
{
stdx::lock_guard<Client> lk(*client.get());
client.get()->setSystemOperationUnkillableByStepdown(lk);
}
AlternativeClientRegion acr(client);
try {
auto opCtx = cc().makeOperationContext();
auto nss = NamespaceString::kSessionTransactionsTableNamespace;
auto deadline = Date_t::now() + Milliseconds(100);
ShouldNotConflictWithSecondaryBatchApplicationBlock shouldNotConflictBlock(
opCtx->lockState());
Lock::DBLock dbLock(opCtx.get(), nss.dbName(), MODE_IS, deadline);
Lock::CollectionLock collLock(opCtx.get(), nss, MODE_IS, deadline);
auto databaseHolder = DatabaseHolder::get(opCtx.get());
auto db = databaseHolder->getDb(opCtx.get(), nss.dbName());
if (!db) {
// There is no config database, so there cannot be any active transactions.
return boost::none;
}
auto collection =
CollectionCatalog::get(opCtx.get())->lookupCollectionByNamespace(opCtx.get(), nss);
if (!collection) {
return boost::none;
}
if (!stableTimestamp.isNull()) {
opCtx->recoveryUnit()->setTimestampReadSource(RecoveryUnit::ReadSource::kProvided,
stableTimestamp);
}
// Scan. We guess that occasional scans are cheaper than the write overhead of an index.
boost::optional<Timestamp> oldestTxnTimestamp;
auto cursor = collection->getCursor(opCtx.get());
while (auto record = cursor->next()) {
auto doc = record.value().data.toBson();
auto txnRecord =
SessionTxnRecord::parse(IDLParserContext("parse oldest active txn record"), doc);
if (txnRecord.getState() != DurableTxnStateEnum::kPrepared &&
txnRecord.getState() != DurableTxnStateEnum::kInProgress) {
continue;
}
// A prepared transaction must have a start timestamp.
invariant(txnRecord.getStartOpTime());
auto ts = txnRecord.getStartOpTime()->getTimestamp();
if (!oldestTxnTimestamp || ts < oldestTxnTimestamp.value()) {
oldestTxnTimestamp = ts;
}
}
return oldestTxnTimestamp;
} catch (const DBException&) {
return exceptionToStatus();
}
}
boost::optional<TxnNumber> TransactionParticipant::Observer::getClientTxnNumber(
const TxnNumberAndRetryCounter& txnNumberAndRetryCounter) const {
if (_isInternalSessionForNonRetryableWrite()) {
return boost::none;
} else if (_isInternalSessionForRetryableWrite()) {
invariant(_sessionId().getTxnNumber());
return _sessionId().getTxnNumber();
}
return {txnNumberAndRetryCounter.getTxnNumber()};
}
Session* TransactionParticipant::Observer::_session() const {
return getTransactionParticipant.owner(_tp);
}
const LogicalSessionId& TransactionParticipant::Observer::_sessionId() const {
return _session()->getSessionId();
}
bool TransactionParticipant::Observer::_isInternalSession() const {
return isChildSession(_sessionId());
}
bool TransactionParticipant::Observer::_isInternalSessionForRetryableWrite() const {
return isInternalSessionForRetryableWrite(_sessionId());
}
bool TransactionParticipant::Observer::_isInternalSessionForNonRetryableWrite() const {
return isInternalSessionForNonRetryableWrite(_sessionId());
}
boost::optional<TxnNumber> TransactionParticipant::Observer::_activeRetryableWriteTxnNumber()
const {
if (_isInternalSessionForNonRetryableWrite()) {
return boost::none;
}
if (_isInternalSessionForRetryableWrite()) {
return *_sessionId().getTxnNumber();
}
invariant(!_isInternalSession());
if (o().txnState.isInRetryableWriteMode()) {
const auto txnNumber = o().activeTxnNumberAndRetryCounter.getTxnNumber();
return txnNumber != kUninitializedTxnNumber ? boost::make_optional(txnNumber) : boost::none;
}
return boost::none;
}
void TransactionParticipant::Participant::_uassertNoConflictingInternalTransactionForRetryableWrite(
OperationContext* opCtx, const TxnNumberAndRetryCounter& txnNumberAndRetryCounter) {
auto clientTxnNumber = getClientTxnNumber(txnNumberAndRetryCounter);
if (!clientTxnNumber) {
// This must be a non-retryable child session transaction so there can't be a conflict.
return;
}
auto& retryableWriteTxnParticipantCatalog =
getRetryableWriteTransactionParticipantCatalog(opCtx);
retryableWriteTxnParticipantCatalog.checkForConflictingInternalTransactions(
opCtx, *clientTxnNumber, txnNumberAndRetryCounter);
}
bool TransactionParticipant::Participant::_verifyCanBeginMultiDocumentTransaction(
OperationContext* opCtx, const TxnNumberAndRetryCounter& txnNumberAndRetryCounter) {
if (txnNumberAndRetryCounter.getTxnNumber() ==
o().activeTxnNumberAndRetryCounter.getTxnNumber()) {
if (txnNumberAndRetryCounter.getTxnRetryCounter() <
o().activeTxnNumberAndRetryCounter.getTxnRetryCounter()) {
uasserted(
TxnRetryCounterTooOldInfo(*o().activeTxnNumberAndRetryCounter.getTxnRetryCounter()),
str::stream() << "Cannot start a transaction at given transaction number "
<< txnNumberAndRetryCounter.getTxnNumber() << " on session "
<< _sessionId() << " using txnRetryCounter "
<< txnNumberAndRetryCounter.getTxnRetryCounter()
<< " because it has already been restarted using a "
<< "higher txnRetryCounter "
<< o().activeTxnNumberAndRetryCounter.getTxnRetryCounter());
} else if (txnNumberAndRetryCounter.getTxnRetryCounter() ==
o().activeTxnNumberAndRetryCounter.getTxnRetryCounter() ||
o().activeTxnNumberAndRetryCounter.getTxnRetryCounter() ==
kUninitializedTxnRetryCounter) {
// Servers in a sharded cluster can start a new transaction at the active transaction
// number to allow internal retries by routers on re-targeting errors, like
// StaleShard/DatabaseVersion or SnapshotTooOld.
uassert(ErrorCodes::ConflictingOperationInProgress,
"Only servers in a sharded cluster can start a new transaction at the active "
"transaction number",
!serverGlobalParams.clusterRole.has(ClusterRole::None));
if (_isInternalSessionForRetryableWrite() &&
o().txnState.isInSet(TransactionState::kCommitted)) {
// This is a retry of a committed internal transaction for retryable writes so
// skip resetting the state and updating the metrics.
return true;
}
_uassertCanReuseActiveTxnNumberForTransaction(opCtx);
} else {
const auto restartableStates = TransactionState::kNone | TransactionState::kInProgress |
TransactionState::kAbortedWithoutPrepare | TransactionState::kAbortedWithPrepare;
uassert(ErrorCodes::IllegalOperation,
str::stream() << "Cannot restart transaction "
<< txnNumberAndRetryCounter.getTxnNumber()
<< " using txnRetryCounter "
<< txnNumberAndRetryCounter.getTxnRetryCounter()
<< " because it is already in state " << o().txnState
<< " with txnRetryCounter "
<< o().activeTxnNumberAndRetryCounter.getTxnRetryCounter(),
o().txnState.isInSet(restartableStates));
}
} else {
invariant(txnNumberAndRetryCounter.getTxnNumber() >
o().activeTxnNumberAndRetryCounter.getTxnNumber());
}
_uassertNoConflictingInternalTransactionForRetryableWrite(opCtx, txnNumberAndRetryCounter);
return false;
}
void TransactionParticipant::Participant::_uassertCanReuseActiveTxnNumberForTransaction(
OperationContext* opCtx) {
if (o().txnState.isInSet(TransactionState::kNone)) {
const auto& retryableWriteTxnParticipantCatalog =
getRetryableWriteTransactionParticipantCatalog(opCtx);
invariant(retryableWriteTxnParticipantCatalog.isValid());
for (const auto& it : retryableWriteTxnParticipantCatalog.getParticipants()) {
const auto& txnParticipant = it.second;
if (txnParticipant._sessionId() == _sessionId()) {
continue;
}
invariant(txnParticipant._isInternalSessionForRetryableWrite());
uassert(
6202002,
str::stream() << "Cannot start transaction with session id " << _sessionId()
<< " and transaction number "
<< o().activeTxnNumberAndRetryCounter.getTxnNumber()
<< " because a retryable write with the same transaction number"
<< " is being executed in a retryable internal transaction "
<< " with session id " << txnParticipant._sessionId()
<< " and transaction number "
<< txnParticipant.getActiveTxnNumberAndRetryCounter().getTxnNumber()
<< " in state " << txnParticipant.o().txnState,
txnParticipant.transactionIsAbortedWithoutPrepare());
}
} else {
uassert(
50911,
str::stream() << "Cannot start a transaction with session id " << _sessionId()
<< " and transaction number "
<< o().activeTxnNumberAndRetryCounter.toBSON()
<< " because a transaction with the same transaction number is in state "
<< o().txnState,
o().txnState.isInSet(TransactionState::kAbortedWithoutPrepare));
}
}
void TransactionParticipant::Participant::_beginOrContinueRetryableWrite(
OperationContext* opCtx, const TxnNumberAndRetryCounter& txnNumberAndRetryCounter) {
invariant(!txnNumberAndRetryCounter.getTxnRetryCounter());
_uassertNoConflictingInternalTransactionForRetryableWrite(opCtx, txnNumberAndRetryCounter);
if (txnNumberAndRetryCounter.getTxnNumber() >
o().activeTxnNumberAndRetryCounter.getTxnNumber()) {
// New retryable write.
_setNewTxnNumberAndRetryCounter(
opCtx, {txnNumberAndRetryCounter.getTxnNumber(), kUninitializedTxnRetryCounter});
p().autoCommit = boost::none;
auto& retryableWriteTxnParticipantCatalog =
getRetryableWriteTransactionParticipantCatalog(opCtx);
retryableWriteTxnParticipantCatalog.addParticipant(*this);
} else {
// Retrying a retryable write.
// If this retryable write's transaction id has been converted to a transaction, and that
// transaction is in prepare, wait for it to exit prepare before throwing
// IncompleteTransactionHistory so the error response's operationTime is inclusive of the
// transaction's 2PC decision, guaranteeing causally consistent sessions will always read
// the transaction's writes.
uassert(ErrorCodes::PreparedTransactionInProgress,
"Retryable write that has been converted to a transaction is in prepare",
!o().txnState.isInSet(TransactionState::kPrepared));
uassert(ErrorCodes::IncompleteTransactionHistory,
"Cannot retry a retryable write that has been converted into a transaction",
o().txnState.isInRetryableWriteMode());
invariant(p().autoCommit == boost::none);
}
}
void TransactionParticipant::Participant::_continueMultiDocumentTransaction(
OperationContext* opCtx, const TxnNumberAndRetryCounter& txnNumberAndRetryCounter) {
uassert(ErrorCodes::NoSuchTransaction,
str::stream()
<< "Given transaction number " << txnNumberAndRetryCounter.getTxnNumber()
<< " does not match any in-progress transactions. The active transaction number is "
<< o().activeTxnNumberAndRetryCounter.getTxnNumber(),
txnNumberAndRetryCounter.getTxnNumber() ==
o().activeTxnNumberAndRetryCounter.getTxnNumber() &&
!o().txnState.isInRetryableWriteMode());
uassert(TxnRetryCounterTooOldInfo(*o().activeTxnNumberAndRetryCounter.getTxnRetryCounter()),
str::stream() << "Cannot continue transaction "
<< txnNumberAndRetryCounter.getTxnNumber() << " on session "
<< _sessionId() << " using txnRetryCounter "
<< txnNumberAndRetryCounter.getTxnRetryCounter()
<< " because it has already been restarted using a higher"
<< " txnRetryCounter "
<< o().activeTxnNumberAndRetryCounter.getTxnRetryCounter(),
txnNumberAndRetryCounter.getTxnRetryCounter() >=
o().activeTxnNumberAndRetryCounter.getTxnRetryCounter());
uassert(ErrorCodes::IllegalOperation,
str::stream() << "Cannot continue transaction "
<< txnNumberAndRetryCounter.getTxnNumber() << " on session "
<< _sessionId() << " using txnNumberAndRetryCounter.getTxnRetryCounter() "
<< txnNumberAndRetryCounter.getTxnRetryCounter()
<< " because it is currently in state " << o().txnState
<< " with txnRetryCounter "
<< o().activeTxnNumberAndRetryCounter.getTxnRetryCounter(),
txnNumberAndRetryCounter.getTxnRetryCounter() ==
o().activeTxnNumberAndRetryCounter.getTxnRetryCounter());
if (o().txnState.isInProgress() && !o().txnResourceStash) {
// This indicates that the first command in the transaction failed but did not implicitly
// abort the transaction. It is not safe to continue the transaction, in particular because
// we have not saved the readConcern from the first statement of the transaction. Mark the
// transaction as active here, since _abortTransactionOnSession() will assume we are
// aborting an active transaction since there are no stashed resources.
{
stdx::lock_guard<Client> lk(*opCtx->getClient());
o(lk).transactionMetricsObserver.onUnstash(
ServerTransactionsMetrics::get(opCtx->getServiceContext()),
opCtx->getServiceContext()->getTickSource());
}
_abortTransactionOnSession(opCtx);
uasserted(
ErrorCodes::NoSuchTransaction,
str::stream()
<< "Transaction with " << txnNumberAndRetryCounter.toBSON()
<< " has been aborted because an earlier command in this transaction failed.");
}
}
void TransactionParticipant::Participant::_beginMultiDocumentTransaction(
OperationContext* opCtx, const TxnNumberAndRetryCounter& txnNumberAndRetryCounter) {
// Aborts any in-progress txns.
_setNewTxnNumberAndRetryCounter(opCtx, txnNumberAndRetryCounter);
p().autoCommit = false;
auto& retryableWriteTxnParticipantCatalog =
getRetryableWriteTransactionParticipantCatalog(opCtx);
if (_isInternalSessionForRetryableWrite()) {
retryableWriteTxnParticipantCatalog.addParticipant(*this);
} else if (!_isInternalSessionForNonRetryableWrite()) {
// Don't reset the RetryableWriteTransactionParticipantCatalog upon starting an internal
// transaction for a non-retryable write since the transaction is unrelated to the
// retryable write or transaction in the original session that the write runs in. In
// addition, it is incorrect to clear the transaction history in the original session since
// the history should be kept until there is a retryable write or transaction with a higher
// txnNumber.
retryableWriteTxnParticipantCatalog.reset();
}
{
stdx::lock_guard<Client> lk(*opCtx->getClient());
o(lk).txnState.transitionTo(TransactionState::kInProgress);
// Start tracking various transactions metrics.
//
// We measure the start time in both microsecond and millisecond resolution. The TickSource
// provides microsecond resolution to record the duration of the transaction. The start
// "wall clock" time can be considered an approximation to the microsecond measurement.
auto now = opCtx->getServiceContext()->getPreciseClockSource()->now();
auto tickSource = opCtx->getServiceContext()->getTickSource();
o(lk).transactionExpireDate = now + Seconds(gTransactionLifetimeLimitSeconds.load());
o(lk).transactionMetricsObserver.onStart(
ServerTransactionsMetrics::get(opCtx->getServiceContext()),
*p().autoCommit,
tickSource,
now,
*o().transactionExpireDate);
invariant(p().transactionOperations.isEmpty());