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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 MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kCommand
#include "mongo/platform/basic.h"
#include "mongo/db/kill_sessions_local.h"
#include "mongo/db/client.h"
#include "mongo/db/cursor_manager.h"
#include "mongo/db/kill_sessions_common.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/service_context.h"
#include "mongo/db/session_catalog.h"
#include "mongo/db/transaction_participant.h"
#include "mongo/logv2/log.h"
namespace mongo {
namespace {
/**
* Shortcut method shared by the various forms of session kill below. Every session kill operation
* consists of the following stages:
* 1) Select the sessions to kill, based on their lsid or owning user account (achieved through the
* 'matcher') and further refining that list through the 'filterFn'.
* 2) If any of the selected sessions are currently checked out, interrupt the owning operation
* context with 'reason' as the code.
* 3) Finish killing the selected and interrupted sessions through the 'killSessionFn'.
*/
void killSessionsAction(
OperationContext* opCtx,
const SessionKiller::Matcher& matcher,
const std::function<bool(const ObservableSession&)>& filterFn,
const std::function<void(OperationContext*, const SessionToKill&)>& killSessionFn,
ErrorCodes::Error reason = ErrorCodes::Interrupted) {
const auto catalog = SessionCatalog::get(opCtx);
std::vector<SessionCatalog::KillToken> sessionKillTokens;
catalog->scanSessions(matcher, [&](const ObservableSession& session) {
if (filterFn(session))
sessionKillTokens.emplace_back(session.kill(reason));
});
for (auto& sessionKillToken : sessionKillTokens) {
auto session = catalog->checkOutSessionForKill(opCtx, std::move(sessionKillToken));
// TODO (SERVER-33850): Rename KillAllSessionsByPattern and
// ScopedKillAllSessionsByPatternImpersonator to not refer to session kill
const KillAllSessionsByPattern* pattern = matcher.match(session.getSessionId());
invariant(pattern);
ScopedKillAllSessionsByPatternImpersonator impersonator(opCtx, *pattern);
killSessionFn(opCtx, session);
}
}
} // namespace
void killSessionsAbortUnpreparedTransactions(OperationContext* opCtx,
const SessionKiller::Matcher& matcher,
ErrorCodes::Error reason) {
killSessionsAction(opCtx,
matcher,
[](const ObservableSession& session) {
auto participant = TransactionParticipant::get(session);
return participant.transactionIsInProgress();
},
[](OperationContext* opCtx, const SessionToKill& session) {
auto participant = TransactionParticipant::get(session);
// This is the same test as in the filter, but we must check again now
// that the session is checked out.
if (participant.transactionIsInProgress()) {
participant.abortTransaction(opCtx);
}
},
reason);
}
SessionKiller::Result killSessionsLocal(OperationContext* opCtx,
const SessionKiller::Matcher& matcher,
SessionKiller::UniformRandomBitGenerator* urbg) {
killSessionsAbortUnpreparedTransactions(opCtx, matcher);
uassertStatusOK(killSessionsLocalKillOps(opCtx, matcher));
auto res = CursorManager::get(opCtx)->killCursorsWithMatchingSessions(opCtx, matcher);
uassertStatusOK(res.first);
return {std::vector<HostAndPort>{}};
}
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);
// If the transaction is aborted here, it means it was aborted after
// the filter. The most likely reason for this is that the transaction
// was active and the session kill aborted it. We still want to log
// that as aborted due to transactionLifetimeLimitSessions.
if (txnParticipant.transactionIsInProgress() || txnParticipant.transactionIsAborted()) {
LOGV2(
20707,
"Aborting transaction with session id {sessionId} and txnNumber {txnNumber} "
"because it has been running for longer than 'transactionLifetimeLimitSeconds'",
"Aborting transaction because it has been running for longer than "
"'transactionLifetimeLimitSeconds'",
"sessionId"_attr = session.getSessionId().getId(),
"txnNumber"_attr = txnParticipant.getActiveTxnNumber());
if (txnParticipant.transactionIsInProgress()) {
txnParticipant.abortTransaction(opCtx);
}
}
},
ErrorCodes::TransactionExceededLifetimeLimitSeconds);
}
void killSessionsLocalShutdownAllTransactions(OperationContext* opCtx) {
SessionKiller::Matcher matcherAllSessions(
KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
killSessionsAction(opCtx,
matcherAllSessions,
[](const ObservableSession& session) {
return TransactionParticipant::get(session).transactionIsOpen();
},
[](OperationContext* opCtx, const SessionToKill& session) {
TransactionParticipant::get(session).shutdown(opCtx);
},
ErrorCodes::InterruptedAtShutdown);
}
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).transactionIsPrepared();
},
[](OperationContext* opCtx, const SessionToKill& session) {
// We're holding the RSTL, so the transaction shouldn't be otherwise
// affected.
invariant(TransactionParticipant::get(session).transactionIsPrepared());
// Abort the prepared transaction and invalidate the session it is
// associated with.
TransactionParticipant::get(session).abortTransaction(opCtx);
TransactionParticipant::get(session).invalidate(opCtx);
});
}
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.
LOGV2(6015318, "Yielding locks for prepared transactions.");
SessionKiller::Matcher matcherAllSessions(
KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(newOpCtx.get())});
killSessionsAction(newOpCtx.get(),
matcherAllSessions,
[](const ObservableSession& session) {
return TransactionParticipant::get(session).transactionIsPrepared();
},
[](OperationContext* killerOpCtx, const SessionToKill& session) {
auto txnParticipant = TransactionParticipant::get(session);
// 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()) {
LOGV2_DEBUG(20708,
3,
"Yielding locks of prepared transaction. SessionId: "
"{sessionId} TxnNumber: {txnNumber}",
"Yielding locks of prepared transaction",
"sessionId"_attr = session.getSessionId().getId(),
"txnNumber"_attr = txnParticipant.getActiveTxnNumber());
txnParticipant.refreshLocksForPreparedTransaction(killerOpCtx, true);
}
},
ErrorCodes::InterruptedDueToReplStateChange);
}
void invalidateSessionsForStepdown(OperationContext* opCtx) {
// It is illegal to invalidate the sessions if the operation has a session checked out.
invariant(!OperationContextSession::get(opCtx));
LOGV2(6015319, "Invalidating sessions for stepdown.");
SessionKiller::Matcher matcherAllSessions(
KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
killSessionsAction(opCtx,
matcherAllSessions,
[](const ObservableSession& session) {
return !TransactionParticipant::get(session).transactionIsPrepared();
},
[](OperationContext* killerOpCtx, const SessionToKill& session) {
auto txnParticipant = TransactionParticipant::get(session);
if (!txnParticipant.transactionIsPrepared()) {
txnParticipant.invalidate(killerOpCtx);
}
},
ErrorCodes::InterruptedDueToReplStateChange);
}
} // namespace mongo
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