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wiredtiger_kv_engine.cpp
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wiredtiger_kv_engine.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_RECOVERY(ID, DLEVEL, MESSAGE, ...) \
LOGV2_DEBUG_OPTIONS(ID, DLEVEL, {logv2::LogComponent::kStorageRecovery}, MESSAGE, ##__VA_ARGS__)
#define LOGV2_FOR_ROLLBACK(ID, DLEVEL, MESSAGE, ...) \
LOGV2_DEBUG_OPTIONS( \
ID, DLEVEL, {logv2::LogComponent::kReplicationRollback}, MESSAGE, ##__VA_ARGS__)
#include "mongo/base/checked_cast.h"
#include "mongo/base/parse_number.h"
#include "mongo/bson/bsonelement.h"
#include "mongo/bson/bsonmisc.h"
#include "mongo/db/catalog/collection_options_gen.h"
#include "mongo/db/index_names.h"
#include "mongo/db/repl/member_state.h"
#include "mongo/db/server_parameter.h"
#include "mongo/db/storage/backup_block.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_oplog_manager.h"
#include "mongo/logv2/log_attr.h"
#include "mongo/logv2/log_component.h"
#include "mongo/logv2/log_severity.h"
#include "mongo/platform/atomic_proxy.h"
#include "mongo/platform/compiler.h"
#include "mongo/stdx/unordered_map.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/duration.h"
#include "mongo/util/exit_code.h"
#include "mongo/util/fail_point.h"
#include "mongo/util/str.h"
#include "mongo/util/uuid.h"
#include "mongo/util/version/releases.h"
#ifdef _WIN32
#define NVALGRIND
#endif
#include <absl/container/node_hash_map.h>
#include <boost/algorithm/string/join.hpp>
#include <boost/filesystem/fstream.hpp>
#include <boost/filesystem/operations.hpp>
#include <boost/filesystem/path.hpp>
#include <boost/none.hpp>
#include <boost/none_t.hpp>
#include <boost/optional.hpp>
#include <boost/preprocessor/control/iif.hpp>
#include <fmt/format.h>
#include <valgrind/valgrind.h>
// IWYU pragma: no_include "boost/system/detail/error_code.hpp"
#include <boost/move/utility_core.hpp>
#include <boost/optional/optional.hpp>
#include <wiredtiger.h>
// IWYU pragma: no_include "cxxabi.h"
#include <algorithm>
#include <cerrno>
#include <chrono>
#include <cstddef>
#include <exception>
#include <iomanip>
#include <memory>
#include <mutex>
#include <sstream>
#include <utility>
#include "mongo/base/error_codes.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/db/bson/dotted_path_support.h"
#include "mongo/db/client.h"
#include "mongo/db/concurrency/exception_util.h"
#include "mongo/db/concurrency/locker.h"
#include "mongo/db/global_settings.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/repl/repl_settings.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/db/server_options.h"
#include "mongo/db/server_recovery.h"
#include "mongo/db/service_context.h"
#include "mongo/db/snapshot_window_options_gen.h"
#include "mongo/db/storage/journal_listener.h"
#include "mongo/db/storage/key_format.h"
#include "mongo/db/storage/storage_file_util.h"
#include "mongo/db/storage/storage_options.h"
#include "mongo/db/storage/storage_parameters_gen.h"
#include "mongo/db/storage/storage_repair_observer.h"
#include "mongo/db/storage/ticketholder_manager.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_column_store.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_cursor.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_customization_hooks.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_extensions.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_global_options.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_index.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_kv_engine.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_parameters_gen.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_record_store.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_session_cache.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_size_storer.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_util.h"
#include "mongo/logv2/log.h"
#include "mongo/platform/atomic_word.h"
#include "mongo/util/background.h"
#include "mongo/util/concurrency/idle_thread_block.h"
#include "mongo/util/debug_util.h"
#include "mongo/util/log_and_backoff.h"
#include "mongo/util/quick_exit.h"
#include "mongo/util/scopeguard.h"
#include "mongo/util/testing_proctor.h"
#include "mongo/util/time_support.h"
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kStorage
using namespace fmt::literals;
namespace mongo {
namespace {
MONGO_FAIL_POINT_DEFINE(WTDropEBUSY);
MONGO_FAIL_POINT_DEFINE(WTPauseStableTimestamp);
MONGO_FAIL_POINT_DEFINE(WTPreserveSnapshotHistoryIndefinitely);
MONGO_FAIL_POINT_DEFINE(WTSetOldestTSToStableTS);
MONGO_FAIL_POINT_DEFINE(WTWriteConflictExceptionForImportCollection);
MONGO_FAIL_POINT_DEFINE(WTWriteConflictExceptionForImportIndex);
MONGO_FAIL_POINT_DEFINE(WTRollbackToStableReturnOnEBUSY);
MONGO_FAIL_POINT_DEFINE(hangBeforeUnrecoverableRollbackError);
MONGO_FAIL_POINT_DEFINE(WTDisableFastShutDown);
const std::string kPinOldestTimestampAtStartupName = "_wt_startup";
#if __has_feature(address_sanitizer)
constexpr bool kAddressSanitizerEnabled = true;
#else
constexpr bool kAddressSanitizerEnabled = false;
#endif
#if __has_feature(thread_sanitizer)
constexpr bool kThreadSanitizerEnabled = true;
#else
constexpr bool kThreadSanitizerEnabled = false;
#endif
boost::filesystem::path getOngoingBackupPath() {
return boost::filesystem::path(storageGlobalParams.dbpath) /
WiredTigerBackup::kOngoingBackupFile;
}
} // namespace
bool WiredTigerFileVersion::shouldDowngrade(bool hasRecoveryTimestamp) {
const auto replCoord = repl::ReplicationCoordinator::get(getGlobalServiceContext());
if (replCoord && replCoord->getMemberState().arbiter()) {
// SERVER-35361: Arbiters will no longer downgrade their data files. To downgrade
// binaries, the user must delete the dbpath. It's not particularly expensive for a
// replica set to re-initialize an arbiter that comes online.
return false;
}
if (!serverGlobalParams.featureCompatibility.isVersionInitialized()) {
// If the FCV document hasn't been read, trust the WT compatibility. MongoD will
// downgrade to the same compatibility it discovered on startup.
return _startupVersion == StartupVersion::IS_44_FCV_42 ||
_startupVersion == StartupVersion::IS_42;
}
// (Generic FCV reference): Only consider downgrading when FCV has been fully downgraded to last
// continuous or last LTS. It's possible for WiredTiger to introduce a data format change in a
// continuous release. This FCV gate must remain across binary version releases.
const auto currentVersion = serverGlobalParams.featureCompatibility.getVersion();
if (currentVersion != multiversion::GenericFCV::kLastContinuous &&
currentVersion != multiversion::GenericFCV::kLastLTS) {
return false;
}
if (getGlobalReplSettings().isReplSet()) {
// If this process is run with `--replSet`, it must have run any startup replication
// recovery and downgrading at this point is safe.
return true;
}
if (hasRecoveryTimestamp) {
// If we're not running with `--replSet`, don't allow downgrades if the node needed to run
// replication recovery. Having a recovery timestamp implies recovery must be run, but it
// was not.
return false;
}
// If there is no `recoveryTimestamp`, then the data should be consistent with the top of
// oplog and downgrading can proceed. This is expected for standalone datasets that use FCV.
return true;
}
std::string WiredTigerFileVersion::getDowngradeString() {
if (!serverGlobalParams.featureCompatibility.isVersionInitialized()) {
invariant(_startupVersion != StartupVersion::IS_44_FCV_44);
switch (_startupVersion) {
case StartupVersion::IS_44_FCV_42:
return "compatibility=(release=3.3)";
case StartupVersion::IS_42:
return "compatibility=(release=3.3)";
default:
MONGO_UNREACHABLE;
}
}
// With the introduction of continuous releases, there are two downgrade paths from kLatest.
// Either to kLastContinuous or kLastLTS. It's possible for the data format to differ between
// kLastContinuous and kLastLTS and we'll need to handle that appropriately here. We only
// consider downgrading when FCV has been fully downgraded.
const auto currentVersion = serverGlobalParams.featureCompatibility.getVersion();
// (Generic FCV reference): This FCV check should exist across LTS binary versions because the
// logic for keeping the WiredTiger release version compatible with the server FCV version will
// be the same across different LTS binary versions.
if (currentVersion == multiversion::GenericFCV::kLastContinuous) {
// If the data format between kLatest and kLastContinuous differs, change the
// 'kLastContinuousWTRelease' version.
return kLastContinuousWTRelease;
// (Generic FCV reference): This FCV check should exist across LTS binary versions because
// the logic for keeping the WiredTiger release version compatible with the server FCV
// version will be the same across different LTS binary versions.
} else if (currentVersion == multiversion::GenericFCV::kLastLTS) {
// If the data format between kLatest and kLastLTS differs, change the
// 'kLastLTSWTRelease' version.
return kLastLTSWTRelease;
}
// We're in a state that's not ready to downgrade. Use the latest WiredTiger version for this
// binary.
return kLatestWTRelease;
}
using std::set;
using std::string;
namespace dps = ::mongo::dotted_path_support;
class WiredTigerKVEngine::WiredTigerSessionSweeper : public BackgroundJob {
public:
explicit WiredTigerSessionSweeper(WiredTigerSessionCache* sessionCache)
: BackgroundJob(false /* deleteSelf */), _sessionCache(sessionCache) {}
virtual string name() const {
return "WTIdleSessionSweeper";
}
virtual void run() {
ThreadClient tc(name(), getGlobalServiceContext());
// TODO(SERVER-74657): Please revisit if this thread could be made killable.
{
stdx::lock_guard<Client> lk(*tc.get());
tc.get()->setSystemOperationUnkillableByStepdown(lk);
}
LOGV2_DEBUG(22303, 1, "starting {name} thread", "name"_attr = name());
while (!_shuttingDown.load()) {
{
stdx::unique_lock<Latch> lock(_mutex);
MONGO_IDLE_THREAD_BLOCK;
// Check every 10 seconds or sooner in the debug builds
_condvar.wait_for(lock, stdx::chrono::seconds(kDebugBuild ? 1 : 10));
}
_sessionCache->closeExpiredIdleSessions(gWiredTigerSessionCloseIdleTimeSecs.load() *
1000);
}
LOGV2_DEBUG(22304, 1, "stopping {name} thread", "name"_attr = name());
}
void shutdown() {
_shuttingDown.store(true);
{
stdx::unique_lock<Latch> lock(_mutex);
// Wake up the session sweeper thread early, we do not want the shutdown
// to wait for us too long.
_condvar.notify_one();
}
wait();
}
private:
WiredTigerSessionCache* _sessionCache;
AtomicWord<bool> _shuttingDown{false};
Mutex _mutex = MONGO_MAKE_LATCH("WiredTigerSessionSweeper::_mutex"); // protects _condvar
// The session sweeper thread idles on this condition variable for a particular time duration
// between cleaning up expired sessions. It can be triggered early to expediate shutdown.
stdx::condition_variable _condvar;
};
std::string toString(const StorageEngine::OldestActiveTransactionTimestampResult& r) {
if (r.isOK()) {
if (r.getValue()) {
// Timestamp.
return r.getValue().value().toString();
} else {
// boost::none.
return "null";
}
} else {
return r.getStatus().toString();
}
}
StringData WiredTigerKVEngine::kTableUriPrefix = "table:"_sd;
WiredTigerKVEngine::WiredTigerKVEngine(OperationContext* opCtx,
const std::string& canonicalName,
const std::string& path,
ClockSource* cs,
const std::string& extraOpenOptions,
size_t cacheSizeMB,
size_t maxHistoryFileSizeMB,
bool ephemeral,
bool repair)
: _clockSource(cs),
_oplogManager(std::make_unique<WiredTigerOplogManager>()),
_canonicalName(canonicalName),
_path(path),
_sizeStorerSyncTracker(cs, 100000, Seconds(60)),
_ephemeral(ephemeral),
_inRepairMode(repair),
_cacheSizeMB(cacheSizeMB) {
_pinnedOplogTimestamp.store(Timestamp::max().asULL());
boost::filesystem::path journalPath = path;
journalPath /= "journal";
if (!_ephemeral) {
if (!boost::filesystem::exists(journalPath)) {
try {
boost::filesystem::create_directory(journalPath);
} catch (std::exception& e) {
LOGV2_ERROR(22312,
"error creating journal dir {directory} {error}",
"Error creating journal directory",
"directory"_attr = journalPath.generic_string(),
"error"_attr = e.what());
throw;
}
}
}
std::stringstream ss;
ss << "create,";
ss << "cache_size=" << cacheSizeMB << "M,";
ss << "session_max=33000,";
ss << "eviction=(threads_min=4,threads_max=4),";
if (gWiredTigerEvictionDirtyTargetGB)
ss << "eviction_dirty_target="
<< static_cast<size_t>(gWiredTigerEvictionDirtyTargetGB * 1024) << "MB,";
if (!gWiredTigerExtraDiagnostics.empty())
ss << "extra_diagnostics=[" << boost::algorithm::join(gWiredTigerExtraDiagnostics, ",")
<< "],";
if (gWiredTigerEvictionDirtyMaxGB)
ss << "eviction_dirty_trigger=" << static_cast<size_t>(gWiredTigerEvictionDirtyMaxGB * 1024)
<< "MB,";
ss << "config_base=false,";
ss << "statistics=(fast),";
if (!WiredTigerSessionCache::isEngineCachingCursors()) {
ss << "cache_cursors=false,";
}
if (_ephemeral) {
// If we've requested an ephemeral instance we store everything into memory instead of
// backing it onto disk. Logging is not supported in this instance, thus we also have to
// disable it.
ss << ",in_memory=true,log=(enabled=false),";
} else {
// In persistent mode we enable the journal and set the compression settings.
ss << "log=(enabled=true,remove=true,path=journal,compressor=";
ss << wiredTigerGlobalOptions.journalCompressor << "),";
ss << "builtin_extension_config=(zstd=(compression_level="
<< wiredTigerGlobalOptions.zstdCompressorLevel << ")),";
}
ss << "file_manager=(close_idle_time=" << gWiredTigerFileHandleCloseIdleTime
<< ",close_scan_interval=" << gWiredTigerFileHandleCloseScanInterval
<< ",close_handle_minimum=" << gWiredTigerFileHandleCloseMinimum << "),";
ss << "statistics_log=(wait=" << wiredTigerGlobalOptions.statisticsLogDelaySecs << "),";
// Enable JSON output for errors and messages.
ss << "json_output=(error,message),";
// Generate the settings related to the verbose configuration.
ss << WiredTigerUtil::generateWTVerboseConfiguration() << ",";
if (kDebugBuild) {
// Do not abort the process when corruption is found in debug builds, which supports
// increased test coverage.
ss << "debug_mode=(corruption_abort=false,";
// For select debug builds, support enabling WiredTiger eviction debug mode. This uses
// more aggressive eviction tactics, but may have a negative performance impact.
if (gWiredTigerEvictionDebugMode) {
ss << "eviction=true,";
}
ss << "),";
}
if constexpr (kAddressSanitizerEnabled || kThreadSanitizerEnabled) {
// For applications using WT, advancing a cursor invalidates the data/memory that cursor was
// pointing to. WT performs the optimization of managing its own memory. The unit of memory
// allocation is a page. Walking a cursor from one key/value to the next often lands on the
// same page, which has the effect of keeping the address of the prior key/value valid. For
// a bug to occur, the cursor must move across pages, and the prior page must be
// evicted. While rare, this can happen, resulting in reading random memory.
//
// The cursor copy debug mode will instead cause WT to malloc/free memory for each key/value
// a cursor is positioned on. Thus, enabling when using with address sanitizer will catch
// many cases of dereferencing invalid cursor positions. Note, there is a known caveat: a
// free/malloc for roughly the same allocation size can often return the same memory
// address. This is a scenario where the address sanitizer is not able to detect a
// use-after-free error.
//
// Additionally, WT does not use the standard C thread model and thus TSAN can report false
// data races when touching memory that was allocated within WT. The cursor_copy mode
// alleviates this by copying all returned data to its own buffer before leaving the storage
// engine.
ss << "debug_mode=(cursor_copy=true),";
}
if constexpr (kThreadSanitizerEnabled) {
// TSAN builds may take longer for certain operations, increase or disable the relevant
// timeouts.
ss << "cache_stuck_timeout_ms=600000,";
ss << "generation_drain_timeout_ms=0,";
}
if (TestingProctor::instance().isEnabled()) {
// Enable debug write-ahead logging for all tables when testing is enabled.
//
// If MongoDB startup fails, there may be clues from the previous run still left in the WT
// log files that can provide some insight into how the system got into a bad state. When
// testing is enabled, keep around some of these files for investigative purposes.
//
// We strive to keep 4 minutes of logs. Increase the retention for tests that take
// checkpoints more often.
const double fourMinutesInSeconds = 240.0;
int ckptsPerFourMinutes;
if (storageGlobalParams.syncdelay <= 0.0) {
ckptsPerFourMinutes = 1;
} else {
ckptsPerFourMinutes =
static_cast<int>(fourMinutesInSeconds / storageGlobalParams.syncdelay);
}
if (ckptsPerFourMinutes < 1) {
LOGV2_WARNING(8423377,
"Unexpected value for checkpoint retention",
"syncdelay"_attr =
static_cast<std::int64_t>(storageGlobalParams.syncdelay),
"ckptsPerFourMinutes"_attr = ckptsPerFourMinutes);
ckptsPerFourMinutes = 1;
}
ss << fmt::format("debug_mode=(table_logging=true,checkpoint_retention={}),",
ckptsPerFourMinutes);
}
if (gWiredTigerStressConfig) {
ss << "timing_stress_for_test=[history_store_checkpoint_delay,checkpoint_slow],";
}
ss << WiredTigerCustomizationHooks::get(getGlobalServiceContext())
->getTableCreateConfig("system");
ss << WiredTigerExtensions::get(getGlobalServiceContext())->getOpenExtensionsConfig();
ss << extraOpenOptions;
if (WiredTigerUtil::willRestoreFromBackup()) {
ss << WiredTigerUtil::generateRestoreConfig() << ",";
}
string config = ss.str();
LOGV2(22315, "Opening WiredTiger", "config"_attr = config);
auto startTime = Date_t::now();
_openWiredTiger(path, config);
LOGV2(4795906, "WiredTiger opened", "duration"_attr = Date_t::now() - startTime);
_eventHandler.setStartupSuccessful();
_wtOpenConfig = config;
{
char buf[(2 * 8 /*bytes in hex*/) + 1 /*nul terminator*/];
invariantWTOK(_conn->query_timestamp(_conn, buf, "get=recovery"), nullptr);
std::uint64_t tmp;
fassert(50758, NumberParser().base(16)(buf, &tmp));
_recoveryTimestamp = Timestamp(tmp);
LOGV2_FOR_RECOVERY(23987,
0,
"WiredTiger recoveryTimestamp",
"recoveryTimestamp"_attr = _recoveryTimestamp);
}
{
char buf[(2 * 8 /*bytes in hex*/) + 1 /*nul terminator*/];
invariantWTOK(_conn->query_timestamp(_conn, buf, "get=oldest"), nullptr);
std::uint64_t tmp;
fassert(5380107, NumberParser().base(16)(buf, &tmp));
if (tmp != 0) {
LOGV2_FOR_RECOVERY(
5380106, 0, "WiredTiger oldestTimestamp", "oldestTimestamp"_attr = Timestamp(tmp));
// The oldest timestamp is set in WT. Only set the in-memory variable.
_oldestTimestamp.store(tmp);
setInitialDataTimestamp(Timestamp(tmp));
}
}
// If there's no recovery timestamp, MDB has not produced a consistent snapshot of
// data. `_oldestTimestamp` and `_initialDataTimestamp` are only meaningful when there's a
// consistent snapshot of data.
//
// Note, this code is defensive (i.e: protects against a theorized, unobserved case) and is
// primarily concerned with restarts of a process that was performing an eMRC=off rollback via
// refetch.
if (_recoveryTimestamp.isNull() && _oldestTimestamp.load() > 0) {
LOGV2_FOR_RECOVERY(5380108, 0, "There is an oldestTimestamp without a recoveryTimestamp");
_oldestTimestamp.store(0);
_initialDataTimestamp.store(0);
}
_sessionCache.reset(new WiredTigerSessionCache(this));
_sessionSweeper = std::make_unique<WiredTigerSessionSweeper>(_sessionCache.get());
_sessionSweeper->go();
// Until the Replication layer installs a real callback, prevent truncating the oplog.
setOldestActiveTransactionTimestampCallback(
[](Timestamp) { return StatusWith(boost::make_optional(Timestamp::min())); });
if (!_ephemeral) {
if (!_recoveryTimestamp.isNull()) {
// If the oldest/initial data timestamps were unset (there was no persisted durable
// history), initialize them to the recovery timestamp.
if (_oldestTimestamp.load() == 0) {
setInitialDataTimestamp(_recoveryTimestamp);
// Communicate the oldest timestamp to WT.
setOldestTimestamp(_recoveryTimestamp, false);
}
// Pin the oldest timestamp prior to calling `setStableTimestamp` as that attempts to
// advance the oldest timestamp. We do this pinning to give features such as resharding
// an opportunity to re-pin the oldest timestamp after a restart. The assumptions this
// relies on are that:
//
// 1) The feature stores the desired pin timestamp in some local collection.
// 2) This temporary pinning lasts long enough for the catalog to be loaded and
// accessed.
{
stdx::lock_guard<Latch> lk(_oldestTimestampPinRequestsMutex);
uassertStatusOK(_pinOldestTimestamp(lk,
kPinOldestTimestampAtStartupName,
Timestamp(_oldestTimestamp.load()),
false));
}
setStableTimestamp(_recoveryTimestamp, false);
_sessionCache->snapshotManager().setLastApplied(_recoveryTimestamp);
}
}
if (_ephemeral && !TestingProctor::instance().isEnabled()) {
// We do not maintain any snapshot history for the ephemeral storage engine in production
// because replication and sharded transactions do not currently run on the inMemory engine.
// It is live in testing, however.
minSnapshotHistoryWindowInSeconds.store(0);
}
_sizeStorerUri = _uri("sizeStorer");
WiredTigerSession session(_conn);
if (repair && _hasUri(session.getSession(), _sizeStorerUri)) {
LOGV2(22316, "Repairing size cache");
auto status = _salvageIfNeeded(opCtx, _sizeStorerUri.c_str());
if (status.code() != ErrorCodes::DataModifiedByRepair)
fassertNoTrace(28577, status);
}
_sizeStorer = std::make_unique<WiredTigerSizeStorer>(_conn, _sizeStorerUri);
_runTimeConfigParam.reset(makeServerParameter<WiredTigerEngineRuntimeConfigParameter>(
"wiredTigerEngineRuntimeConfig", ServerParameterType::kRuntimeOnly));
_runTimeConfigParam->_data.second = this;
}
WiredTigerKVEngine::~WiredTigerKVEngine() {
// Remove server parameters that we added in the constructor, to enable unit tests to reload the
// storage engine again in this same process.
ServerParameterSet::getNodeParameterSet()->remove("wiredTigerEngineRuntimeConfig");
cleanShutdown();
_sessionCache.reset(nullptr);
}
void WiredTigerKVEngine::notifyStartupComplete() {
unpinOldestTimestamp(kPinOldestTimestampAtStartupName);
WiredTigerUtil::notifyStartupComplete();
}
void WiredTigerKVEngine::appendGlobalStats(OperationContext* opCtx, BSONObjBuilder& b) {
BSONObjBuilder bb(b.subobjStart("concurrentTransactions"));
auto ticketHolderManager = TicketHolderManager::get(opCtx->getServiceContext());
ticketHolderManager->appendStats(bb);
bb.done();
}
/**
* Table of MongoDB<->WiredTiger<->Log version numbers:
*
* | MongoDB | WiredTiger | Log |
* |------------------------+------------+-----|
* | 3.0.15 | 2.5.3 | 1 |
* | 3.2.20 | 2.9.2 | 1 |
* | 3.4.15 | 2.9.2 | 1 |
* | 3.6.4 | 3.0.1 | 2 |
* | 4.0.16 | 3.1.1 | 3 |
* | 4.2.1 | 3.2.2 | 3 |
* | 4.2.6 | 3.3.0 | 3 |
* | 4.2.6 (blessed by 4.4) | 3.3.0 | 4 |
* | 4.4.0 | 10.0.0 | 5 |
* | 5.0.0 | 10.0.1 | 5 |
* | 5.1.0 | 10.0.1 | 5 |
* | 5.2.0 | 10.0.1 | 5 |
*/
void WiredTigerKVEngine::_openWiredTiger(const std::string& path, const std::string& wtOpenConfig) {
// MongoDB 4.4 will always run in compatibility version 10.0.
std::string configStr = wtOpenConfig + ",compatibility=(require_min=\"10.0.0\")";
auto wtEventHandler = _eventHandler.getWtEventHandler();
int ret = wiredtiger_open(path.c_str(), wtEventHandler, configStr.c_str(), &_conn);
if (!ret) {
_fileVersion = {WiredTigerFileVersion::StartupVersion::IS_44_FCV_44};
return;
}
if (_eventHandler.isWtIncompatible()) {
// WT 4.4+ will refuse to startup on datafiles left behind by 4.0 and earlier. This behavior
// is enforced outside of `require_min`. This condition is detected via a specific error
// message from WiredTiger.
if (_inRepairMode) {
// In case this process was started with `--repair`, remove the "repair incomplete"
// file.
StorageRepairObserver::get(getGlobalServiceContext())->onRepairDone(nullptr);
}
LOGV2_FATAL_NOTRACE(
4671205,
"This version of MongoDB is too recent to start up on the existing data files. "
"Try MongoDB 4.2 or earlier.");
}
// MongoDB 4.4 doing clean shutdown in FCV 4.2 will use compatibility version 3.3.
configStr = wtOpenConfig + ",compatibility=(require_min=\"3.3.0\")";
ret = wiredtiger_open(path.c_str(), wtEventHandler, configStr.c_str(), &_conn);
if (!ret) {
_fileVersion = {WiredTigerFileVersion::StartupVersion::IS_44_FCV_42};
return;
}
// MongoDB 4.2 uses compatibility version 3.2.
configStr = wtOpenConfig + ",compatibility=(require_min=\"3.2.0\")";
ret = wiredtiger_open(path.c_str(), wtEventHandler, configStr.c_str(), &_conn);
if (!ret) {
_fileVersion = {WiredTigerFileVersion::StartupVersion::IS_42};
return;
}
LOGV2_WARNING(22347,
"Failed to start up WiredTiger under any compatibility version. This may be due "
"to an unsupported upgrade or downgrade.");
if (ret == EINVAL) {
fassertFailedNoTrace(28561);
}
if (ret == WT_TRY_SALVAGE) {
LOGV2_WARNING(22348, "WiredTiger metadata corruption detected");
if (!_inRepairMode) {
LOGV2_FATAL_NOTRACE(50944, kWTRepairMsg);
}
}
if (!_inRepairMode) {
LOGV2_FATAL_NOTRACE(
28595, "Terminating.", "reason"_attr = wtRCToStatus(ret, nullptr).reason());
}
// Always attempt to salvage metadata regardless of error code when in repair mode.
LOGV2_WARNING(22349, "Attempting to salvage WiredTiger metadata");
configStr = wtOpenConfig + ",salvage=true";
ret = wiredtiger_open(path.c_str(), wtEventHandler, configStr.c_str(), &_conn);
if (!ret) {
StorageRepairObserver::get(getGlobalServiceContext())
->invalidatingModification("WiredTiger metadata salvaged");
return;
}
LOGV2_FATAL_NOTRACE(50947,
"Failed to salvage WiredTiger metadata",
"details"_attr = wtRCToStatus(ret, nullptr).reason());
}
void WiredTigerKVEngine::cleanShutdown() {
LOGV2(22317, "WiredTigerKVEngine shutting down");
if (!_conn) {
return;
}
// these must be the last things we do before _conn->close();
haltOplogManager(/*oplogRecordStore=*/nullptr, /*shuttingDown=*/true);
if (_sessionSweeper) {
LOGV2(22318, "Shutting down session sweeper thread");
_sessionSweeper->shutdown();
LOGV2(22319, "Finished shutting down session sweeper thread");
}
LOGV2_FOR_RECOVERY(23988,
2,
"Shutdown timestamps.",
"Stable Timestamp"_attr = Timestamp(_stableTimestamp.load()),
"Initial Data Timestamp"_attr = Timestamp(_initialDataTimestamp.load()),
"Oldest Timestamp"_attr = Timestamp(_oldestTimestamp.load()));
_sessionCache->shuttingDown();
syncSizeInfo(/*syncToDisk=*/true);
// The size storer has to be destructed after the session cache has shut down. This sets the
// shutdown flag internally in the session cache. As operations get interrupted during shutdown,
// they release their session back to the session cache. If the shutdown flag has been set,
// released sessions will skip flushing the size storer.
_sizeStorer.reset();
// We want WiredTiger to leak memory for faster shutdown except when we are running tools to
// look for memory leaks.
bool leak_memory = !kAddressSanitizerEnabled;
std::string closeConfig = "";
if (RUNNING_ON_VALGRIND) { // NOLINT
leak_memory = false;
}
if (MONGO_unlikely(WTDisableFastShutDown.shouldFail())) {
leak_memory = false;
}
if (leak_memory) {
closeConfig = "leak_memory=true,";
}
const Timestamp stableTimestamp = getStableTimestamp();
const Timestamp initialDataTimestamp = getInitialDataTimestamp();
if (gTakeUnstableCheckpointOnShutdown || initialDataTimestamp.asULL() <= 1) {
closeConfig += "use_timestamp=false,";
} else if (!serverGlobalParams.enableMajorityReadConcern &&
stableTimestamp < initialDataTimestamp) {
// After a rollback via refetch, WT update chains for _id index keys can be logically
// corrupt for read timestamps earlier than the `_initialDataTimestamp`. Because the stable
// timestamp is really a read timestamp, we must avoid taking a stable checkpoint.
//
// If a stable timestamp is not set, there's no risk of reading corrupt history.
LOGV2(22326,
"Skipping checkpoint during clean shutdown because stableTimestamp is less than the "
"initialDataTimestamp and enableMajorityReadConcern is false",
"stableTimestamp"_attr = stableTimestamp,
"initialDataTimestamp"_attr = initialDataTimestamp);
quickExit(ExitCode::clean);
}
if (_fileVersion.shouldDowngrade(!_recoveryTimestamp.isNull())) {
auto startTime = Date_t::now();
LOGV2(22324,
"Closing WiredTiger in preparation for reconfiguring",
"closeConfig"_attr = closeConfig);
invariantWTOK(_conn->close(_conn, closeConfig.c_str()), nullptr);
LOGV2(4795905, "WiredTiger closed", "duration"_attr = Date_t::now() - startTime);
startTime = Date_t::now();
invariantWTOK(
wiredtiger_open(
_path.c_str(), _eventHandler.getWtEventHandler(), _wtOpenConfig.c_str(), &_conn),
nullptr);
LOGV2(4795904, "WiredTiger re-opened", "duration"_attr = Date_t::now() - startTime);
startTime = Date_t::now();
LOGV2(22325, "Reconfiguring", "newConfig"_attr = _fileVersion.getDowngradeString());
invariantWTOK(_conn->reconfigure(_conn, _fileVersion.getDowngradeString().c_str()),
nullptr);
LOGV2(4795903, "Reconfigure complete", "duration"_attr = Date_t::now() - startTime);
}
auto startTime = Date_t::now();
LOGV2(4795902, "Closing WiredTiger", "closeConfig"_attr = closeConfig);
invariantWTOK(_conn->close(_conn, closeConfig.c_str()), nullptr);
LOGV2(4795901, "WiredTiger closed", "duration"_attr = Date_t::now() - startTime);
_conn = nullptr;
}
int64_t WiredTigerKVEngine::getIdentSize(OperationContext* opCtx, StringData ident) {
WiredTigerSession* session = WiredTigerRecoveryUnit::get(opCtx)->getSession();
return WiredTigerUtil::getIdentSize(session->getSession(), _uri(ident));
}
Status WiredTigerKVEngine::repairIdent(OperationContext* opCtx, StringData ident) {
WiredTigerSession* session = WiredTigerRecoveryUnit::get(opCtx)->getSession();
string uri = _uri(ident);
session->closeAllCursors(uri);
_sessionCache->closeAllCursors(uri);
if (isEphemeral()) {
return Status::OK();
}
_ensureIdentPath(ident);
return _salvageIfNeeded(opCtx, uri.c_str());
}
Status WiredTigerKVEngine::_salvageIfNeeded(OperationContext* opCtx, const char* uri) {
// Using a side session to avoid transactional issues
WiredTigerSession sessionWrapper(_conn);
WT_SESSION* session = sessionWrapper.getSession();
int rc = (session->verify)(session, uri, nullptr);
// WT may return EBUSY if the database contains dirty data. If we checkpoint and retry the
// operation it will attempt to clean up the dirty elements during checkpointing, thus allowing
// the operation to succeed if it was the only reason to fail.
if (rc == EBUSY) {
_checkpoint(opCtx, session);
rc = (session->verify)(session, uri, nullptr);
}
if (rc == 0) {
LOGV2(22327, "Verify succeeded. Not salvaging.", "uri"_attr = uri);
return Status::OK();
}
if (rc == ENOENT) {
LOGV2_WARNING(22350,
"Data file is missing. Attempting to drop and re-create the collection.",
"uri"_attr = uri);
return _rebuildIdent(opCtx, session, uri);
}
LOGV2(22328, "Verify failed. Running a salvage operation.", "uri"_attr = uri);
rc = session->salvage(session, uri, nullptr);
// Same reasoning for handling EBUSY errors as above.
if (rc == EBUSY) {
_checkpoint(opCtx, session);
rc = session->salvage(session, uri, nullptr);
}
auto status = wtRCToStatus(rc, session, "Salvage failed:");
if (status.isOK()) {
return {ErrorCodes::DataModifiedByRepair, str::stream() << "Salvaged data for " << uri};
}
LOGV2_WARNING(22351,
"Salvage failed. The file will be moved out of "
"the way and a new ident will be created.",
"uri"_attr = uri,
"error"_attr = status);
// If the data is unsalvageable, we should completely rebuild the ident.
return _rebuildIdent(opCtx, session, uri);
}
Status WiredTigerKVEngine::_rebuildIdent(OperationContext* opCtx,
WT_SESSION* session,
const char* uri) {
invariant(_inRepairMode);
invariant(std::string(uri).find(kTableUriPrefix.rawData()) == 0);
const std::string identName(uri + kTableUriPrefix.size());
auto filePath = getDataFilePathForIdent(identName);
if (filePath) {
const boost::filesystem::path corruptFile(filePath->string() + ".corrupt");
LOGV2_WARNING(22352,
"Moving data file {file} to backup as {backup}",
"Moving data file to backup",
"file"_attr = filePath->generic_string(),
"backup"_attr = corruptFile.generic_string());
auto status = fsyncRename(filePath.value(), corruptFile);
if (!status.isOK()) {
return status;
}
}
LOGV2_WARNING(22353, "Rebuilding ident {ident}", "Rebuilding ident", "ident"_attr = identName);
// This is safe to call after moving the file because it only reads from the metadata, and not
// the data file itself.
auto swMetadata = WiredTigerUtil::getMetadataCreate(session, uri);
if (!swMetadata.isOK()) {
auto status = swMetadata.getStatus();
LOGV2_ERROR(22357,
"Failed to get metadata for {uri}",
"Rebuilding ident failed: failed to get metadata",
"uri"_attr = uri,
"error"_attr = status);
return status;
}
int rc = session->drop(session, uri, nullptr);
// WT may return EBUSY if the database contains dirty data. If we checkpoint and retry the
// operation it will attempt to clean up the dirty elements during checkpointing, thus allowing
// the operation to succeed if it was the only reason to fail.
if (rc == EBUSY) {
_checkpoint(opCtx, session);
rc = session->drop(session, uri, nullptr);
}
if (rc != 0) {
auto status = wtRCToStatus(rc, session);
LOGV2_ERROR(22358,
"Failed to drop {uri}",
"Rebuilding ident failed: failed to drop",
"uri"_attr = uri,
"error"_attr = status);
return status;
}
rc = session->create(session, uri, swMetadata.getValue().c_str());
if (rc != 0) {
auto status = wtRCToStatus(rc, session);
LOGV2_ERROR(22359,
"Failed to create {uri} with config: {config}",
"Rebuilding ident failed: failed to create with config",
"uri"_attr = uri,
"config"_attr = swMetadata.getValue(),
"error"_attr = status);
return status;
}
LOGV2(22329, "Successfully re-created table", "uri"_attr = uri);
return {ErrorCodes::DataModifiedByRepair,
str::stream() << "Re-created empty data file for " << uri};
}
void WiredTigerKVEngine::flushAllFiles(OperationContext* opCtx, bool callerHoldsReadLock) {
LOGV2_DEBUG(22330, 1, "WiredTigerKVEngine::flushAllFiles");
if (_ephemeral) {
return;
}
const Timestamp stableTimestamp = getStableTimestamp();
const Timestamp initialDataTimestamp = getInitialDataTimestamp();
uassert(
5841000,
"Cannot take checkpoints when the stable timestamp is less than the initial data timestamp",
initialDataTimestamp == Timestamp::kAllowUnstableCheckpointsSentinel ||
stableTimestamp >= initialDataTimestamp);
// Immediately flush the size storer information to disk. When the node is fsync locked for
// operations such as backup, it's imperative that we copy the most up-to-date data files.
syncSizeInfo(true);
// If there's no journal (ephemeral), we must checkpoint all of the data.
WiredTigerSessionCache::Fsync fsyncType = !_ephemeral
? WiredTigerSessionCache::Fsync::kCheckpointStableTimestamp
: WiredTigerSessionCache::Fsync::kCheckpointAll;
// We will skip updating the journal listener if the caller holds read locks.
// The JournalListener may do writes, and taking write locks would conflict with the read locks.
WiredTigerSessionCache::UseJournalListener useListener = callerHoldsReadLock
? WiredTigerSessionCache::UseJournalListener::kSkip
: WiredTigerSessionCache::UseJournalListener::kUpdate;
_sessionCache->waitUntilDurable(opCtx, fsyncType, useListener);
}
Status WiredTigerKVEngine::beginBackup(OperationContext* opCtx) {
invariant(!_backupSession);
// The inMemory Storage Engine cannot create a backup cursor.
if (_ephemeral) {
return Status::OK();
}