void yieldLocksForPreparedTransactions(OperationContext* opCtx) {
// Create a new opCtx because we need an empty locker to refresh the locks.
auto newClient = opCtx->getServiceContext()->makeClient("prepared-txns-yield-locks");
AlternativeClientRegion acr(newClient);
auto newOpCtx = cc().makeOperationContext();
// Scan the sessions again to get the list of all sessions with prepared transaction
// to yield their locks.
SessionKiller::Matcher matcherAllSessions(
KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(newOpCtx.get())});
killSessionsAction(
newOpCtx.get(),
matcherAllSessions,
[](const ObservableSession& session) {
return TransactionParticipant::get(session.get())->transactionIsPrepared();
},
[](OperationContext* killerOpCtx, const SessionToKill& session) {
auto const txnParticipant = TransactionParticipant::get(session.get());
// Yield locks for prepared transactions.
// When scanning and killing operations, all prepared transactions are included in the
// list. Even though new sessions may be created after the scan, none of them can become
// prepared during stepdown, since the RSTL has been enqueued, preventing any new
// writes.
if (txnParticipant->transactionIsPrepared()) {
LOG(3) << "Yielding locks of prepared transaction. SessionId: "
<< session.getSessionId().getId()
<< " TxnNumber: " << txnParticipant->getActiveTxnNumber();
txnParticipant->refreshLocksForPreparedTransaction(killerOpCtx, true);
}
});
}
void MongoDSessionCatalog::onStepUp(OperationContext* opCtx) {
// Invalidate sessions that could have a retryable write on it, so that we can refresh from disk
// in case the in-memory state was out of sync.
const auto catalog = SessionCatalog::get(opCtx);
// The use of shared_ptr here is in order to work around the limitation of stdx::function that
// the functor must be copyable.
auto sessionKillTokens = std::make_shared<std::vector<SessionCatalog::KillToken>>();
// Scan all sessions and reacquire locks for prepared transactions.
// There may be sessions that are checked out during this scan, but none of them
// can be prepared transactions, since only oplog application can make transactions
// prepared on secondaries and oplog application has been stopped at this moment.
std::vector<LogicalSessionId> sessionIdToReacquireLocks;
SessionKiller::Matcher matcher(
KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
catalog->scanSessions(matcher, [&](const ObservableSession& session) {
const auto txnParticipant = TransactionParticipant::get(session.get());
if (!txnParticipant->inMultiDocumentTransaction()) {
sessionKillTokens->emplace_back(session.kill());
}
if (txnParticipant->transactionIsPrepared()) {
sessionIdToReacquireLocks.emplace_back(session.getSessionId());
}
});
killSessionTokensFunction(opCtx, sessionKillTokens);
{
// Create a new opCtx because we need an empty locker to refresh the locks.
auto newClient = opCtx->getServiceContext()->makeClient("restore-prepared-txn");
AlternativeClientRegion acr(newClient);
for (const auto& sessionId : sessionIdToReacquireLocks) {
auto newOpCtx = cc().makeOperationContext();
newOpCtx->setLogicalSessionId(sessionId);
MongoDOperationContextSession ocs(newOpCtx.get());
auto txnParticipant =
TransactionParticipant::get(OperationContextSession::get(newOpCtx.get()));
txnParticipant->refreshLocksForPreparedTransaction(newOpCtx.get(), false);
}
}
const size_t initialExtentSize = 0;
const bool capped = false;
const bool maxSize = 0;
BSONObj result;
DBDirectClient client(opCtx);
if (client.createCollection(NamespaceString::kSessionTransactionsTableNamespace.ns(),
initialExtentSize,
capped,
maxSize,
&result)) {
return;
}
const auto status = getStatusFromCommandResult(result);
if (status == ErrorCodes::NamespaceExists) {
return;
}
uassertStatusOKWithContext(status,
str::stream()
<< "Failed to create the "
<< NamespaceString::kSessionTransactionsTableNamespace.ns()
<< " collection");
}