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 killSessionsLocalShutdownAllTransactions(OperationContext* opCtx) {
SessionKiller::Matcher matcherAllSessions(
KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
killSessionsAction(opCtx,
matcherAllSessions,
[](const ObservableSession&) { return true; },
[](OperationContext* opCtx, const SessionToKill& session) {
TransactionParticipant::get(session.get())->shutdown();
},
ErrorCodes::InterruptedAtShutdown);
}
void killSessionsAbortUnpreparedTransactions(OperationContext* opCtx,
const SessionKiller::Matcher& matcher,
ErrorCodes::Error reason) {
killSessionsAction(
opCtx,
matcher,
[](const ObservableSession& session) {
return !TransactionParticipant::get(session.get())->transactionIsPrepared();
},
[](OperationContext* opCtx, const SessionToKill& session) {
TransactionParticipant::get(session.get())->abortArbitraryTransaction();
},
reason);
}
void killSessionsAbortUnpreparedTransactions(OperationContext* opCtx,
const SessionKiller::Matcher& matcher,
ErrorCodes::Error reason) {
killSessionsAction(
opCtx,
matcher,
[](const ObservableSession& session) {
auto participant = TransactionParticipant::get(session);
return participant.inMultiDocumentTransaction() && !participant.transactionIsPrepared();
},
[](OperationContext* opCtx, const SessionToKill& session) {
TransactionParticipant::get(session).abortTransactionIfNotPrepared(opCtx);
},
reason);
}
void killSessionsAbortAllPreparedTransactions(OperationContext* opCtx) {
SessionKiller::Matcher matcherAllSessions(
KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
killSessionsAction(
opCtx,
matcherAllSessions,
[](const ObservableSession& session) {
// Filter for sessions that have a prepared transaction.
return TransactionParticipant::get(session.get())->transactionIsPrepared();
},
[](OperationContext* opCtx, const SessionToKill& session) {
// Abort the prepared transaction and invalidate the session it is
// associated with.
TransactionParticipant::get(session.get())->abortPreparedTransactionForRollback();
});
}
void killAllExpiredTransactions(OperationContext* opCtx) {
SessionKiller::Matcher matcherAllSessions(
KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
killSessionsAction(
opCtx,
matcherAllSessions,
[when = opCtx->getServiceContext()->getPreciseClockSource()->now()](
const ObservableSession& session) {
return TransactionParticipant::get(session).expiredAsOf(when);
},
[](OperationContext* opCtx, const SessionToKill& session) {
auto txnParticipant = TransactionParticipant::get(session);
log()
<< "Aborting transaction with txnNumber " << txnParticipant.getActiveTxnNumber()
<< " on session " << session.getSessionId().getId()
<< " because it has been running for longer than 'transactionLifetimeLimitSeconds'";
txnParticipant.abortTransactionIfNotPrepared(opCtx);
},
ErrorCodes::ExceededTimeLimit);
}
void killAllExpiredTransactions(OperationContext* opCtx) {
SessionKiller::Matcher matcherAllSessions(
KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
killSessionsAction(
opCtx,
matcherAllSessions,
[when = opCtx->getServiceContext()->getPreciseClockSource()->now()](
const ObservableSession& session) {
return TransactionParticipant::get(session.get())->expired();
},
[](OperationContext* opCtx, const SessionToKill& session) {
auto txnParticipant = TransactionParticipant::get(session.get());
LOG(0)
<< "Aborting transaction with txnNumber " << txnParticipant->getActiveTxnNumber()
<< " on session " << session.getSessionId().getId()
<< " because it has been running for longer than 'transactionLifetimeLimitSeconds'";
// The try/catch block below is necessary because expiredAsOf() in the filterFn above
// could return true for expired, but unprepared transaction, but by the time we get to
// actually kill it, the participant could theoretically become prepared (being under
// the SessionCatalog mutex doesn't prevent the concurrently running thread from doing
// preparing the participant).
//
// Then when the execution reaches the killSessionFn, it would find the transaction is
// prepared and not allowed to be killed, which would cause the exception below
try {
txnParticipant->abortArbitraryTransaction();
} catch (const DBException& ex) {
// TODO(schwerin): Can we catch a more specific exception?
warning() << "May have failed to abort expired transaction on session "
<< session.getSessionId().getId() << " due to " << redact(ex.toStatus());
}
},
ErrorCodes::ExceededTimeLimit);
}