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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_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kReplicationRollback
#include "mongo/platform/basic.h"
#include "mongo/db/repl/rs_rollback.h"
#include <algorithm>
#include <memory>
#include "mongo/bson/bsonelement_comparator.h"
#include "mongo/bson/util/bson_extract.h"
#include "mongo/db/auth/authorization_manager.h"
#include "mongo/db/catalog/collection_catalog.h"
#include "mongo/db/catalog/database_holder.h"
#include "mongo/db/catalog/document_validation.h"
#include "mongo/db/catalog/index_build_oplog_entry.h"
#include "mongo/db/catalog/index_catalog.h"
#include "mongo/db/catalog/rename_collection.h"
#include "mongo/db/catalog_raii.h"
#include "mongo/db/client.h"
#include "mongo/db/commands.h"
#include "mongo/db/commands/txn_cmds_gen.h"
#include "mongo/db/concurrency/replication_state_transition_lock_guard.h"
#include "mongo/db/concurrency/write_conflict_exception.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/dbhelpers.h"
#include "mongo/db/exec/working_set_common.h"
#include "mongo/db/index_builds_coordinator.h"
#include "mongo/db/logical_session_id.h"
#include "mongo/db/logical_time_validator.h"
#include "mongo/db/ops/delete.h"
#include "mongo/db/ops/update.h"
#include "mongo/db/ops/update_request.h"
#include "mongo/db/query/internal_plans.h"
#include "mongo/db/read_write_concern_defaults.h"
#include "mongo/db/repl/bgsync.h"
#include "mongo/db/repl/drop_pending_collection_reaper.h"
#include "mongo/db/repl/oplog.h"
#include "mongo/db/repl/oplog_interface.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/db/repl/replication_coordinator_impl.h"
#include "mongo/db/repl/replication_process.h"
#include "mongo/db/repl/roll_back_local_operations.h"
#include "mongo/db/repl/rollback_source.h"
#include "mongo/db/repl/rslog.h"
#include "mongo/db/s/shard_identity_rollback_notifier.h"
#include "mongo/db/session_catalog_mongod.h"
#include "mongo/db/storage/durable_catalog.h"
#include "mongo/db/storage/remove_saver.h"
#include "mongo/db/transaction_participant.h"
#include "mongo/logv2/log.h"
#include "mongo/s/client/shard_registry.h"
#include "mongo/s/grid.h"
#include "mongo/util/exit.h"
#include "mongo/util/fail_point.h"
#include "mongo/util/scopeguard.h"
namespace mongo {
using std::list;
using std::map;
using std::pair;
using std::set;
using std::shared_ptr;
using std::string;
using std::unique_ptr;
namespace repl {
MONGO_FAIL_POINT_DEFINE(rollbackExitEarlyAfterCollectionDrop);
using namespace rollback_internal;
bool DocID::operator<(const DocID& other) const {
int comp = uuid.toString().compare(other.uuid.toString());
if (comp < 0)
return true;
if (comp > 0)
return false;
const StringData::ComparatorInterface* stringComparator = nullptr;
BSONElementComparator eltCmp(BSONElementComparator::FieldNamesMode::kIgnore, stringComparator);
return eltCmp.evaluate(_id < other._id);
}
bool DocID::operator==(const DocID& other) const {
// Since this is only used for tests, going with the simple impl that reuses operator< which is
// used in the real code.
return !(*this < other || other < *this);
}
void FixUpInfo::removeAllDocsToRefetchFor(UUID collectionUUID) {
docsToRefetch.erase(docsToRefetch.lower_bound(DocID::minFor(collectionUUID)),
docsToRefetch.upper_bound(DocID::maxFor(collectionUUID)));
}
void FixUpInfo::removeRedundantOperations() {
for (const auto& collectionUUID : collectionsToDrop) {
removeAllDocsToRefetchFor(collectionUUID);
indexesToDrop.erase(collectionUUID);
indexesToCreate.erase(collectionUUID);
collectionsToRename.erase(collectionUUID);
collectionsToResyncMetadata.erase(collectionUUID);
}
}
bool FixUpInfo::removeRedundantIndexCommands(UUID uuid, std::string indexName) {
LOGV2_DEBUG(21659,
2,
"Attempting to remove redundant index operations from the set of indexes to create "
"for collection {uuid}, for index '{indexName}'",
"uuid"_attr = uuid,
"indexName"_attr = indexName);
// See if there are any indexes to create for this collection.
auto indexes = indexesToCreate.find(uuid);
// There are no indexes to create for this collection UUID, so there are no index creation
// operations to remove.
if (indexes == indexesToCreate.end()) {
LOGV2_DEBUG(21660,
2,
"Collection {uuid} has no indexes to create. Not removing any index creation "
"operations for index '{indexName}'.",
"uuid"_attr = uuid,
"indexName"_attr = indexName);
return false;
}
// This is the set of all indexes to create for the given collection UUID. Keep a reference so
// we can modify the original object.
std::map<std::string, BSONObj>* indexesToCreateForColl = &(indexes->second);
// If this index was not previously added to the set of indexes that need to be created for this
// collection, then we do nothing.
if (indexesToCreateForColl->find(indexName) == indexesToCreateForColl->end()) {
LOGV2_DEBUG(21661,
2,
"Index '{indexName}' was not previously set to be created for collection "
"{uuid}. Not removing any index creation operations.",
"indexName"_attr = indexName,
"uuid"_attr = uuid);
return false;
}
// This index was previously added to the set of indexes to create for this collection, so we
// remove it from that set.
LOGV2_DEBUG(21662,
2,
"Index '{indexName}' was previously set to be created for collection {uuid}. "
"Removing this redundant index creation operation.",
"indexName"_attr = indexName,
"uuid"_attr = uuid);
indexesToCreateForColl->erase(indexName);
// If there are now no remaining indexes to create for this collection, remove it from
// the set of collections that we need to create indexes for.
if (indexesToCreateForColl->empty()) {
indexesToCreate.erase(uuid);
}
return true;
}
void FixUpInfo::recordRollingBackDrop(const NamespaceString& nss, OpTime opTime, UUID uuid) {
// Records the collection that needs to be removed from the drop-pending collections
// list in the DropPendingCollectionReaper.
collectionsToRemoveFromDropPendingCollections.emplace(uuid, std::make_pair(opTime, nss));
// Records the collection drop as a rename from the drop pending
// namespace to its namespace before it was dropped.
RenameCollectionInfo info;
info.renameTo = nss;
info.renameFrom = nss.makeDropPendingNamespace(opTime);
// We do not need to check if there is already an entry in collectionsToRename
// for this collection because it is not possible that a renameCollection occurs
// on the same collection after it has been dropped. Thus, we know that this
// will be the first RenameCollectionInfo entry for this collection and do not
// need to change the renameFrom entry to account for multiple renames.
collectionsToRename[uuid] = info;
}
Status FixUpInfo::recordDropTargetInfo(const BSONElement& dropTarget,
const BSONObj& obj,
OpTime opTime) {
StatusWith<UUID> dropTargetUUIDStatus = UUID::parse(dropTarget);
if (!dropTargetUUIDStatus.isOK()) {
std::string message = str::stream()
<< "Unable to roll back renameCollection. Cannot parse "
"dropTarget UUID. Returned status: "
<< redact(dropTargetUUIDStatus.getStatus()) << ", oplog entry: " << redact(obj);
LOGV2_ERROR(21729, "{message}", "message"_attr = message);
return dropTargetUUIDStatus.getStatus();
}
UUID dropTargetUUID = dropTargetUUIDStatus.getValue();
// The namespace of the collection that was dropped is the same namespace
// that we are trying to rename the collection to.
NamespaceString droppedNs(obj.getStringField("to"));
// Records the information necessary for undoing the dropTarget.
recordRollingBackDrop(droppedNs, opTime, dropTargetUUID);
return Status::OK();
}
Status rollback_internal::updateFixUpInfoFromLocalOplogEntry(OperationContext* opCtx,
const OplogInterface& localOplog,
FixUpInfo& fixUpInfo,
const BSONObj& ourObj,
bool isNestedApplyOpsCommand) {
// Checks that the oplog entry is smaller than 512 MB. We do not roll back if the
// oplog entry is larger than 512 MB.
if (ourObj.objsize() > 512 * 1024 * 1024)
throw RSFatalException(str::stream()
<< "Rollback too large, oplog size: " << ourObj.objsize());
// If required fields are not present in the BSONObj for an applyOps entry, create these fields
// and populate them with dummy values before parsing ourObj as an oplog entry.
BSONObjBuilder bob;
if (isNestedApplyOpsCommand) {
if (!ourObj.hasField(OplogEntry::kTimestampFieldName)) {
bob.appendTimestamp(OplogEntry::kTimestampFieldName);
}
if (!ourObj.hasField(OplogEntry::kWallClockTimeFieldName)) {
bob.append(OplogEntry::kWallClockTimeFieldName, Date_t());
}
}
bob.appendElements(ourObj);
BSONObj fixedObj = bob.obj();
// Parse the oplog entry.
const OplogEntry oplogEntry(fixedObj);
if (isNestedApplyOpsCommand) {
LOGV2_DEBUG(21663,
2,
"Updating rollback FixUpInfo for nested applyOps oplog entry: {oplogEntry}",
"oplogEntry"_attr = redact(oplogEntry.toBSON()));
}
// Extract the op's collection namespace and UUID.
NamespaceString nss = oplogEntry.getNss();
auto uuid = oplogEntry.getUuid();
if (oplogEntry.getOpType() == OpTypeEnum::kNoop)
return Status::OK();
if (oplogEntry.getNss().isEmpty()) {
throw RSFatalException(str::stream() << "Local op on rollback has no ns: "
<< redact(oplogEntry.toBSON()));
}
auto obj = oplogEntry.getOperationToApply();
if (obj.isEmpty()) {
throw RSFatalException(str::stream() << "Local op on rollback has no object field: "
<< redact(oplogEntry.toBSON()));
}
// If the operation being rolled back has a txnNumber, then the corresponding entry in the
// session transaction table needs to be refetched.
const auto& operationSessionInfo = oplogEntry.getOperationSessionInfo();
auto txnNumber = operationSessionInfo.getTxnNumber();
if (txnNumber) {
auto sessionId = operationSessionInfo.getSessionId();
invariant(sessionId);
auto transactionTableUUID = fixUpInfo.transactionTableUUID;
if (transactionTableUUID) {
BSONObjBuilder txnBob;
txnBob.append("_id", sessionId->toBSON());
auto txnObj = txnBob.obj();
DocID txnDoc(txnObj, txnObj.firstElement(), transactionTableUUID.get());
txnDoc.ns = NamespaceString::kSessionTransactionsTableNamespace.ns();
fixUpInfo.docsToRefetch.insert(txnDoc);
fixUpInfo.refetchTransactionDocs = true;
} else {
throw RSFatalException(
str::stream() << NamespaceString::kSessionTransactionsTableNamespace.ns()
<< " does not have a UUID, but local op has a transaction number: "
<< redact(oplogEntry.toBSON()));
}
if (oplogEntry.isPartialTransaction()) {
// If this is a transaction which did not commit, we need do nothing more than
// rollback the transaction table entry. If it did commit, we will have rolled it
// back when we rolled back the commit.
return Status::OK();
}
}
if (oplogEntry.getOpType() == OpTypeEnum::kCommand) {
// The first element of the object is the name of the command
// and the collection it is acting on, e.x. {renameCollection: "test.x"}.
BSONElement first = obj.firstElement();
switch (oplogEntry.getCommandType()) {
case OplogEntry::CommandType::kCreate: {
// Example create collection oplog entry
// {
// ts: ...,
// h: ...,
// op: "c",
// ns: "foo.$cmd",
// ui: BinData(...),
// o: {
// create: "abc", ...
// }
// ...
// }
fixUpInfo.collectionsToDrop.insert(*uuid);
return Status::OK();
}
case OplogEntry::CommandType::kDrop: {
// Example drop collection oplog entry
// {
// ts: ...,
// h: ...,
// op: "c",
// ns: "foo.$cmd",
// ui: BinData(...),
// o: {
// drop: "abc"
// }
// ...
// }
NamespaceString collectionNamespace(nss.getSisterNS(first.valuestr()));
// Registers the collection to be removed from the drop pending collection
// reaper and to be renamed from its drop pending namespace to original namespace.
fixUpInfo.recordRollingBackDrop(collectionNamespace, oplogEntry.getOpTime(), *uuid);
return Status::OK();
}
case OplogEntry::CommandType::kDropIndexes: {
// Example drop indexes objects
// o: {
// dropIndexes: "x",
// index: "x_1"
// }
// o2:{
// v: 2,
// key: { x: 1 },
// name: "x_1",
// ns: "foo.x"
// }
string ns = nss.db().toString() + '.' + first.valuestr();
string indexName;
auto status = bsonExtractStringField(obj, "index", &indexName);
if (!status.isOK()) {
LOGV2_FATAL(21731,
"Missing index name in dropIndexes operation on rollback, "
"document: {oplogEntry}",
"oplogEntry"_attr = redact(oplogEntry.toBSON()));
throw RSFatalException(
"Missing index name in dropIndexes operation on rollback.");
}
BSONObj obj2 = oplogEntry.getObject2().get().getOwned();
// Inserts the index name and the index spec of the index to be created into the map
// of index name and index specs that need to be created for the given collection.
//
// If this dropped index was a two-phase index build, we add it to the list to
// build in the foreground, without the IndexBuildsCoordinator, since we have no
// knowledge of the original build UUID information. If no start or commit oplog
// entries are rolled-back, this forces the index build to complete before rollback
// finishes.
//
// If we find by processing earlier oplog entries that the commit or abort
// entries are also rolled-back, we will instead rebuild the index with the
// Coordinator so it can wait for a replicated commit or abort.
fixUpInfo.indexesToCreate[*uuid].insert(
std::pair<std::string, BSONObj>(indexName, obj2));
return Status::OK();
}
case OplogEntry::CommandType::kCreateIndexes: {
// Example create indexes obj
// o:{
// createIndex: x,
// v: 2,
// key: { x: 1 },
// name: "x_1",
// }
string indexName;
auto status = bsonExtractStringField(obj, "name", &indexName);
if (!status.isOK()) {
LOGV2_FATAL(21732,
"Missing index name in createIndexes operation on rollback, "
"document: {oplogEntry}",
"oplogEntry"_attr = redact(oplogEntry.toBSON()));
throw RSFatalException(
"Missing index name in createIndexes operation on rollback.");
}
// Checks if a drop was previously done on this index. If so, we remove it from the
// indexesToCreate because a dropIndex and createIndex operation on the same
// collection for the same index cancel each other out. We do not record the
// createIndexes command in the fixUpInfo struct since applying both of these
// commands will lead to the same final state as not applying either of the
// commands. We only cancel out in the direction of [create] -> [drop] indexes
// because it is possible that in the [drop] -> [create] direction, when we create
// an index with the same name it may have a different index spec from that index
// that was previously dropped.
if (fixUpInfo.removeRedundantIndexCommands(*uuid, indexName)) {
return Status::OK();
}
// Inserts the index name to be dropped into the set of indexes that
// need to be dropped for the collection. Any errors dropping the index are ignored
// if it does not exist.
fixUpInfo.indexesToDrop[*uuid].insert(indexName);
return Status::OK();
}
case OplogEntry::CommandType::kStartIndexBuild: {
auto swIndexBuildOplogEntry = IndexBuildOplogEntry::parse(oplogEntry);
if (!swIndexBuildOplogEntry.isOK()) {
return {ErrorCodes::UnrecoverableRollbackError,
str::stream()
<< "Error parsing 'startIndexBuild' oplog entry: "
<< swIndexBuildOplogEntry.getStatus() << ": " << redact(obj)};
}
auto& indexBuildOplogEntry = swIndexBuildOplogEntry.getValue();
// If the index build has been committed or aborted, and the commit or abort
// oplog entry has also been rolled back, the index build will have been added
// to the set to be restarted. An index build may also be in the set to be restarted
// if it was in-progress and aborted before rollback.
// Remove it, and then add it to the set to be dropped. If the index has already
// been dropped by abort, then this is a no-op.
auto& buildsToRestart = fixUpInfo.indexBuildsToRestart;
auto buildUUID = indexBuildOplogEntry.buildUUID;
auto existingIt = buildsToRestart.find(buildUUID);
if (existingIt != buildsToRestart.end()) {
LOGV2_DEBUG(
21664,
2,
"Index build that was previously marked to be restarted will now be "
"dropped due to a rolled-back 'startIndexBuild' oplog entry: {buildUUID}",
"buildUUID"_attr = buildUUID);
buildsToRestart.erase(existingIt);
// If the index build was committed or aborted, we must mark the index as
// needing to be dropped. Add each index to drop by name individually.
for (auto& indexName : indexBuildOplogEntry.indexNames) {
fixUpInfo.indexesToDrop[*uuid].insert(indexName);
}
// Intentionally allow this index build to be added to both 'indexesToDrop' and
// 'unfinishedIndexesToDrop', since we can not tell at this point if it is
// finished or not.
}
// If the index build was not committed or aborted, the index build is
// unfinished in the catalog will need to be dropped before any other collection
// operations.
for (auto& indexName : indexBuildOplogEntry.indexNames) {
fixUpInfo.unfinishedIndexesToDrop[*uuid].insert(indexName);
}
return Status::OK();
}
case OplogEntry::CommandType::kAbortIndexBuild: {
auto swIndexBuildOplogEntry = IndexBuildOplogEntry::parse(oplogEntry);
if (!swIndexBuildOplogEntry.isOK()) {
return {ErrorCodes::UnrecoverableRollbackError,
str::stream()
<< "Error parsing 'abortIndexBuild' oplog entry: "
<< swIndexBuildOplogEntry.getStatus() << ": " << redact(obj)};
}
auto& indexBuildOplogEntry = swIndexBuildOplogEntry.getValue();
auto& buildsToRestart = fixUpInfo.indexBuildsToRestart;
auto buildUUID = indexBuildOplogEntry.buildUUID;
invariant(buildsToRestart.find(buildUUID) == buildsToRestart.end(),
str::stream()
<< "Tried to restart an index build after rolling back an "
"'abortIndexBuild' oplog entry, but a build with the same "
"UUID is already marked to be restarted: "
<< buildUUID);
LOGV2_DEBUG(21665,
2,
"Index build will be restarted after a rolled-back 'abortIndexBuild': "
"{buildUUID}",
"buildUUID"_attr = buildUUID);
IndexBuildDetails details{*uuid};
for (auto& spec : indexBuildOplogEntry.indexSpecs) {
invariant(spec.isOwned());
details.indexSpecs.emplace_back(spec);
}
buildsToRestart.insert({buildUUID, details});
return Status::OK();
}
case OplogEntry::CommandType::kCommitIndexBuild: {
auto swIndexBuildOplogEntry = IndexBuildOplogEntry::parse(oplogEntry);
if (!swIndexBuildOplogEntry.isOK()) {
return {ErrorCodes::UnrecoverableRollbackError,
str::stream()
<< "Error parsing 'commitIndexBuild' oplog entry: "
<< swIndexBuildOplogEntry.getStatus() << ": " << redact(obj)};
}
auto& indexBuildOplogEntry = swIndexBuildOplogEntry.getValue();
// If a dropIndexes oplog entry was already rolled-back, the index build needs to
// be restarted, but not committed. If the index is in the set to be created, then
// its drop was rolled-back and it should be removed.
auto& toCreate = fixUpInfo.indexesToCreate[*uuid];
for (auto& indexName : indexBuildOplogEntry.indexNames) {
auto existing = toCreate.find(indexName);
if (existing != toCreate.end()) {
toCreate.erase(existing);
}
}
// Add the index build to be restarted.
auto& buildsToRestart = fixUpInfo.indexBuildsToRestart;
auto buildUUID = indexBuildOplogEntry.buildUUID;
invariant(buildsToRestart.find(buildUUID) == buildsToRestart.end(),
str::stream()
<< "Tried to restart an index build after rolling back a "
"'commitIndexBuild' oplog entry, but a build with the same "
"UUID is already marked to be restarted: "
<< buildUUID);
LOGV2_DEBUG(21666,
2,
"Index build will be restarted after a rolled-back 'commitIndexBuild': "
"{buildUUID}",
"buildUUID"_attr = buildUUID);
IndexBuildDetails details{*uuid};
for (auto& spec : indexBuildOplogEntry.indexSpecs) {
invariant(spec.isOwned());
details.indexSpecs.emplace_back(spec);
}
buildsToRestart.insert({buildUUID, details});
return Status::OK();
}
case OplogEntry::CommandType::kRenameCollection: {
// Example rename collection obj
// o:{
// renameCollection: "foo.x",
// to: "foo.y",
// stayTemp: false,
// dropTarget: BinData(...),
// }
// dropTarget will be false if no collection is dropped during the rename.
// The ui field will contain the UUID of the new collection that is created.
BSONObj cmd = obj;
std::string ns = first.valuestrsafe();
if (ns.empty()) {
std::string message = str::stream()
<< "Collection name missing from oplog entry: " << redact(obj);
LOGV2(21667, "{message}", "message"_attr = message);
return Status(ErrorCodes::UnrecoverableRollbackError, message);
}
// Checks if dropTarget is present. If it has a UUID value, we need to
// make sure to un-drop the collection that was dropped in the process
// of renaming.
if (auto dropTarget = obj.getField("dropTarget")) {
auto status =
fixUpInfo.recordDropTargetInfo(dropTarget, obj, oplogEntry.getOpTime());
if (!status.isOK()) {
return status;
}
}
RenameCollectionInfo info;
info.renameTo = NamespaceString(ns);
info.renameFrom = NamespaceString(obj.getStringField("to"));
// Checks if this collection has been renamed before within the same database.
// If it has been, update the renameFrom field of the RenameCollectionInfo
// that we will use to create the oplog entry necessary to rename the
// collection back to its original state.
auto collToRename = fixUpInfo.collectionsToRename.find(*uuid);
if (collToRename != fixUpInfo.collectionsToRename.end()) {
info.renameFrom = (*collToRename).second.renameFrom;
}
fixUpInfo.collectionsToRename[*uuid] = info;
// Because of the stayTemp field, we add any collections that have been renamed
// to collectionsToResyncMetadata to ensure that the collection is properly set
// as either a temporary or permanent collection.
fixUpInfo.collectionsToResyncMetadata.insert(*uuid);
return Status::OK();
}
case OplogEntry::CommandType::kDropDatabase: {
// Example drop database oplog entry
// {
// ts: ...,
// h: ...,
// op: "c",
// ns: "foo.$cmd",
// o:{
// "dropDatabase": 1
// }
// ...
// }
// Since we wait for all internal collection drops to be committed before recording
// a 'dropDatabase' oplog entry, this will always create an empty database.
// Creating an empty database doesn't mean anything, so we do nothing.
return Status::OK();
}
case OplogEntry::CommandType::kCollMod: {
for (auto field : obj) {
// Example collMod obj
// o:{
// collMod : "x",
// validationLevel : "off",
// index: {
// name: "indexName_1",
// expireAfterSeconds: 600
// }
// }
const auto modification = field.fieldNameStringData();
if (modification == "collMod") {
continue; // Skips the command name. The first field in the obj will be the
// command name.
}
if (modification == "validator" || modification == "validationAction" ||
modification == "validationLevel") {
fixUpInfo.collectionsToResyncMetadata.insert(*uuid);
continue;
}
// Some collMod fields cannot be rolled back, such as the index field.
string message = "Cannot roll back a collMod command: ";
LOGV2_FATAL(21733,
"{message}{obj}",
"message"_attr = message,
"obj"_attr = redact(obj));
throw RSFatalException(message);
}
return Status::OK();
}
case OplogEntry::CommandType::kApplyOps: {
// Example Apply Ops oplog entry
//{
// op : "c",
// ns : admin.$cmd,
// o : {
// applyOps : [ {
// op : "u", // must be idempotent!
// ns : "test.x",
// ui : BinData(...),
// o2 : {
// _id : 1
// },
// o : {
// _id : 2
// }
// }]
// }
// }
// Additionally, for transactions, applyOps entries may be linked by their
// previousTransactionOpTimes. For those, we need to walk the chain and get to
// all the entries. We don't worry about the order that we walk the entries.
auto operations = first;
auto prevWriteOpTime = oplogEntry.getPrevWriteOpTimeInTransaction();
auto txnHistoryIter = prevWriteOpTime
? localOplog.makeTransactionHistoryIterator(*prevWriteOpTime)
: nullptr;
do {
if (operations.type() != Array) {
std::string message = str::stream()
<< "Expected applyOps argument to be an array; found "
<< redact(operations);
LOGV2_FATAL(21734, "{message}", "message"_attr = message);
return Status(ErrorCodes::UnrecoverableRollbackError, message);
}
for (const auto& subopElement : operations.Array()) {
if (subopElement.type() != Object) {
std::string message = str::stream()
<< "Expected applyOps operations to be of Object type, but found "
<< redact(subopElement);
LOGV2_FATAL(21735, "{message}", "message"_attr = message);
return Status(ErrorCodes::UnrecoverableRollbackError, message);
}
// In applyOps, the object contains an array of different oplog entries, we
// call
// updateFixUpInfoFromLocalOplogEntry here in order to record the
// information
// needed for rollback that is contained within the applyOps, creating a
// nested
// call.
auto subStatus = updateFixUpInfoFromLocalOplogEntry(
opCtx, localOplog, fixUpInfo, subopElement.Obj(), true);
if (!subStatus.isOK()) {
return subStatus;
}
}
if (!txnHistoryIter || !txnHistoryIter->hasNext())
break;
try {
auto nextApplyOps = txnHistoryIter->next(opCtx);
operations = nextApplyOps.getObject().firstElement();
} catch (const DBException& ex) {
// If we can't get the full transaction history, we can't roll back;
return {ErrorCodes::UnrecoverableRollbackError, ex.reason()};
}
} while (1);
return Status::OK();
}
case OplogEntry::CommandType::kAbortTransaction: {
return Status::OK();
}
default: {
std::string message = str::stream() << "Can't roll back this command yet: "
<< " cmdname = " << first.fieldName();
LOGV2_FATAL(21736,
"{message} document: {obj}",
"message"_attr = message,
"obj"_attr = redact(obj));
throw RSFatalException(message);
}
}
}
// If we are inserting/updating/deleting a document in the oplog entry, we will update
// the doc._id field when we actually insert the docID into the docsToRefetch set.
DocID doc = DocID(fixedObj, BSONElement(), *uuid);
doc._id = oplogEntry.getIdElement();
if (doc._id.eoo()) {
std::string message = str::stream() << "Cannot roll back op with no _id. ns: " << nss.ns();
LOGV2_FATAL(21737,
"{message}, document: {oplogEntry}",
"message"_attr = message,
"oplogEntry"_attr = redact(oplogEntry.toBSON()));
throw RSFatalException(message);
}
fixUpInfo.docsToRefetch.insert(doc);
return Status::OK();
}
namespace {
/**
* This must be called before making any changes to our local data and after fetching any
* information from the upstream node. If any information is fetched from the upstream node after we
* have written locally, the function must be called again.
*/
void checkRbidAndUpdateMinValid(OperationContext* opCtx,
const int rbid,
const RollbackSource& rollbackSource,
ReplicationProcess* replicationProcess) {
// It is important that the steps are performed in order to avoid racing with upstream
// rollbacks.
// 1. Gets the last doc in their oplog.
// 2. Gets their RBID and fail if it has changed.
// 3. Sets our minValid to the previously fetched OpTime of the top of their oplog.
const auto newMinValidDoc = rollbackSource.getLastOperation();
if (newMinValidDoc.isEmpty()) {
uasserted(40500, "rollback error newest oplog entry on source is missing or empty");
}
if (rbid != rollbackSource.getRollbackId()) {
// Our source rolled back so the data we received is not necessarily consistent.
uasserted(40508, "rollback rbid on source changed during rollback, canceling this attempt");
}
// We have items we are writing that aren't from a point-in-time. Thus, it is best not to come
// online until we get to that point in freshness. In other words, we do not transition from
// RECOVERING state to SECONDARY state until we have reached the minValid oplog entry.
OpTime minValid = fassert(40492, OpTime::parseFromOplogEntry(newMinValidDoc));
LOGV2(21668, "Setting minvalid to {minValid}", "minValid"_attr = minValid);
// This method is only used with storage engines that do not support recover to stable
// timestamp. As a result, the timestamp on the 'appliedThrough' update does not matter.
invariant(!opCtx->getServiceContext()->getStorageEngine()->supportsRecoverToStableTimestamp());
replicationProcess->getConsistencyMarkers()->clearAppliedThrough(opCtx, {});
replicationProcess->getConsistencyMarkers()->setMinValid(opCtx, minValid);
if (MONGO_unlikely(rollbackHangThenFailAfterWritingMinValid.shouldFail())) {
// This log output is used in jstests so please leave it.
LOGV2(21669,
"rollback - rollbackHangThenFailAfterWritingMinValid fail point "
"enabled. Blocking until fail point is disabled.");
while (MONGO_unlikely(rollbackHangThenFailAfterWritingMinValid.shouldFail())) {
invariant(!globalInShutdownDeprecated()); // It is an error to shutdown while enabled.
mongo::sleepsecs(1);
}
uasserted(40502,
"failing rollback due to rollbackHangThenFailAfterWritingMinValid fail point");
}
}
/**
* Drops an index from the collection based on its name by removing it from the indexCatalog of the
* collection.
*/
void dropIndex(OperationContext* opCtx,
IndexCatalog* indexCatalog,
const string& indexName,
NamespaceString& nss) {
bool includeUnfinishedIndexes = true;
auto indexDescriptor =
indexCatalog->findIndexByName(opCtx, indexName, includeUnfinishedIndexes);
if (!indexDescriptor) {
LOGV2_WARNING(21725,
"Rollback failed to drop index {indexName} in {ns}: index not found.",
"indexName"_attr = indexName,
"ns"_attr = nss.toString());
return;
}
WriteUnitOfWork wunit(opCtx);
auto entry = indexCatalog->getEntry(indexDescriptor);
if (entry->isReady(opCtx)) {
auto status = indexCatalog->dropIndex(opCtx, indexDescriptor);
if (!status.isOK()) {
LOGV2_FATAL(21738,
"Rollback failed to drop index {indexName} in {ns}: {status}",
"indexName"_attr = indexName,
"ns"_attr = nss.toString(),
"status"_attr = redact(status));
}
} else {
auto status = indexCatalog->dropUnfinishedIndex(opCtx, indexDescriptor);
if (!status.isOK()) {
LOGV2_FATAL(21739,
"Rollback failed to drop unfinished index {indexName} in {ns}: {status}",
"indexName"_attr = indexName,
"ns"_attr = nss.toString(),
"status"_attr = redact(status));
}
}
wunit.commit();
}
/**
* Rolls back all createIndexes operations for the collection by dropping the
* created indexes.
*/
void rollbackCreateIndexes(OperationContext* opCtx, UUID uuid, std::set<std::string> indexNames) {
boost::optional<NamespaceString> nss =
CollectionCatalog::get(opCtx).lookupNSSByUUID(opCtx, uuid);
invariant(nss);
Lock::DBLock dbLock(opCtx, nss->db(), MODE_X);
Collection* collection = CollectionCatalog::get(opCtx).lookupCollectionByUUID(opCtx, uuid);
// If we cannot find the collection, we skip over dropping the index.
if (!collection) {
LOGV2_DEBUG(21670,
2,
"Cannot find the collection with uuid: {uuid} in CollectionCatalog during roll "
"back of a createIndexes command.",
"uuid"_attr = uuid.toString());
return;
}
// If we cannot find the index catalog, we skip over dropping the index.
auto indexCatalog = collection->getIndexCatalog();
if (!indexCatalog) {
LOGV2_DEBUG(21671,
2,
"Cannot find the index catalog in collection with uuid: {uuid} during roll "
"back of a createIndexes command.",
"uuid"_attr = uuid.toString());
return;
}
for (auto itIndex = indexNames.begin(); itIndex != indexNames.end(); itIndex++) {
const string& indexName = *itIndex;
LOGV2(21672,
"Dropping index in rollback for collection: {ns}, UUID: {uuid}, index: {indexName}",
"ns"_attr = *nss,
"uuid"_attr = uuid,
"indexName"_attr = indexName);
dropIndex(opCtx, indexCatalog, indexName, *nss);
LOGV2_DEBUG(
21673,
1,
"Dropped index in rollback for collection: {ns}, UUID: {uuid}, index: {indexName}",
"ns"_attr = *nss,
"uuid"_attr = uuid,
"indexName"_attr = indexName);
}
}
/**
* Rolls back all the dropIndexes operations for the collection by re-creating
* the indexes that were dropped.
*/
void rollbackDropIndexes(OperationContext* opCtx,
UUID uuid,
std::map<std::string, BSONObj> indexNames) {
boost::optional<NamespaceString> nss =
CollectionCatalog::get(opCtx).lookupNSSByUUID(opCtx, uuid);
invariant(nss);
Lock::DBLock dbLock(opCtx, nss->db(), MODE_IX);
Lock::CollectionLock collLock(opCtx, *nss, MODE_X);
Collection* collection = CollectionCatalog::get(opCtx).lookupCollectionByNamespace(opCtx, *nss);
// If we cannot find the collection, we skip over dropping the index.
if (!collection) {
LOGV2_DEBUG(21674,
2,
"Cannot find the collection with uuid: {uuid}in CollectionCatalog during roll "
"back of a dropIndexes command.",
"uuid"_attr = uuid.toString());
return;
}
for (auto itIndex = indexNames.begin(); itIndex != indexNames.end(); itIndex++) {
const string indexName = itIndex->first;
BSONObj indexSpec = itIndex->second;
LOGV2(21675,
"Creating index in rollback for collection: {ns}, UUID: {uuid}, index: {indexName}",
"ns"_attr = *nss,
"uuid"_attr = uuid,
"indexName"_attr = indexName);
createIndexForApplyOps(opCtx, indexSpec, *nss, OplogApplication::Mode::kRecovering);
LOGV2_DEBUG(
21676,
1,
"Created index in rollback for collection: {ns}, UUID: {uuid}, index: {indexName}",
"ns"_attr = *nss,
"uuid"_attr = uuid,
"indexName"_attr = indexName);
}
}
/**
* Drops the given collection from the database.
*/
void dropCollection(OperationContext* opCtx,
NamespaceString nss,
Collection* collection,
Database* db) {
if (RollbackImpl::shouldCreateDataFiles()) {
RemoveSaver removeSaver("rollback", "", collection->uuid().toString());
LOGV2(21677,
"Rolling back createCollection on {ns}: Preparing to write documents to a rollback "
"file for a collection with uuid {collection_uuid} to "
"{file}",
"ns"_attr = nss,
"collection_uuid"_attr = collection->uuid(),
"file"_attr = removeSaver.file().generic_string());
// Performs a collection scan and writes all documents in the collection to disk
// in order to keep an archive of items that were rolled back.
auto exec = InternalPlanner::collectionScan(
opCtx, nss.toString(), collection, PlanExecutor::YIELD_AUTO);
BSONObj curObj;
PlanExecutor::ExecState execState;
while (PlanExecutor::ADVANCED == (execState = exec->getNext(&curObj, nullptr))) {
auto status = removeSaver.goingToDelete(curObj);
if (!status.isOK()) {
LOGV2_FATAL(21740,
"Rolling back createCollection on {ns} failed to write document to "
"remove saver file: {status}",
"ns"_attr = nss,
"status"_attr = redact(status));
throw RSFatalException(
"Rolling back createCollection. Failed to write document to remove saver "
"file.");
}
}
// If we exited the above for loop with any other execState than IS_EOF, this means that
// a FAILURE state was returned. If a FAILURE state was returned, either an unrecoverable
// error was thrown by exec, or we attempted to retrieve data that could not be provided
// by the PlanExecutor. In both of these cases it is necessary for a full resync of the
// server.
if (execState != PlanExecutor::IS_EOF) {
if (execState == PlanExecutor::FAILURE &&
WorkingSetCommon::isValidStatusMemberObject(curObj)) {
Status errorStatus = WorkingSetCommon::getMemberObjectStatus(curObj);
LOGV2_FATAL(21741,
"Rolling back createCollection on {ns} failed with {errorStatus}. A "
"full resync is necessary.",
"ns"_attr = nss,
"errorStatus"_attr = redact(errorStatus));
throw RSFatalException(
"Rolling back createCollection failed. A full resync is necessary.");
} else {
LOGV2_FATAL(
21742,
"Rolling back createCollection on {ns} failed. A full resync is necessary.",
"ns"_attr = nss);
throw RSFatalException(
"Rolling back createCollection failed. A full resync is necessary.");
}
}
}
WriteUnitOfWork wunit(opCtx);
// We permanently drop the collection rather than 2-phase drop the collection
// here. By not passing in an opTime to dropCollectionEvenIfSystem() the collection
// is immediately dropped.
fassert(40504, db->dropCollectionEvenIfSystem(opCtx, nss));
wunit.commit();
}
/**
* Renames a collection out of the way when another collection during rollback
* is attempting to use the same namespace.
*/
void renameOutOfTheWay(OperationContext* opCtx, RenameCollectionInfo info, Database* db) {
// Finds the UUID of the collection that we are renaming out of the way.
auto collection =
CollectionCatalog::get(opCtx).lookupCollectionByNamespace(opCtx, info.renameTo);
invariant(collection);
// The generated unique collection name is only guaranteed to exist if the database is
// exclusively locked.
invariant(opCtx->lockState()->isDbLockedForMode(db->name(), LockMode::MODE_X));
// Creates the oplog entry to temporarily rename the collection that is
// preventing the renameCollection command from rolling back to a unique
// namespace.
auto tmpNameResult = db->makeUniqueCollectionNamespace(opCtx, "rollback.tmp%%%%%");
if (!tmpNameResult.isOK()) {
LOGV2_FATAL(21743,
"Unable to generate temporary namespace to rename collection {renameTo} "
"out of the way. {status}",
"renameTo"_attr = info.renameTo,
"status"_attr = tmpNameResult.getStatus().reason());
throw RSFatalException(
"Unable to generate temporary namespace to rename collection out of the way.");
}
const auto& tempNss = tmpNameResult.getValue();
LOGV2_DEBUG(21678,
2,
"Attempted to rename collection from {renameFrom} to {renameTo} but "
"collection exists already. Temporarily renaming collection "
"with UUID {collection_uuid} out of the way to {tempNs}",
"renameFrom"_attr = info.renameFrom,
"renameTo"_attr = info.renameTo,
"collection_uuid"_attr = collection->uuid(),
"tempNs"_attr = tempNss);
// Renaming the collection that was clashing with the attempted rename
// operation to a different collection name.
auto uuid = collection->uuid();
auto renameStatus = renameCollectionForRollback(opCtx, tempNss, uuid);
if (!renameStatus.isOK()) {
LOGV2_FATAL(21744,
"Unable to rename collection {renameTo} out of the way to {tempNs}",
"renameTo"_attr = info.renameTo,
"tempNs"_attr = tempNss);
throw RSFatalException("Unable to rename collection out of the way");
}
}
/**
* Rolls back a renameCollection operation on the given collection.
*/
void rollbackRenameCollection(OperationContext* opCtx, UUID uuid, RenameCollectionInfo info) {
auto dbName = info.renameFrom.db();
LOGV2(21679,
"Attempting to rename collection with UUID: {uuid}, from: {renameFrom}, to: "
"{renameTo}",
"uuid"_attr = uuid,
"renameFrom"_attr = info.renameFrom,
"renameTo"_attr = info.renameTo);
Lock::DBLock dbLock(opCtx, dbName, MODE_X);
auto databaseHolder = DatabaseHolder::get(opCtx);
auto db = databaseHolder->openDb(opCtx, dbName);
invariant(db);
auto status = renameCollectionForRollback(opCtx, info.renameTo, uuid);
// If we try to roll back a collection to a collection name that currently exists
// because another collection was renamed or created with the same collection name,
// we temporarily rename the conflicting collection.
if (status == ErrorCodes::NamespaceExists) {
renameOutOfTheWay(opCtx, info, db);
// Retrying to renameCollection command again now that the conflicting
// collection has been renamed out of the way.
status = renameCollectionForRollback(opCtx, info.renameTo, uuid);
if (!status.isOK()) {
LOGV2_FATAL(21745,
"Rename collection failed to roll back twice. We were unable to rename "
"collection {renameFrom} to {renameTo}. {status}",
"renameFrom"_attr = info.renameFrom,
"renameTo"_attr = info.renameTo,
"status"_attr = status.toString());
throw RSFatalException(
"Rename collection failed to roll back twice. We were unable to rename "
"the collection.");
}
} else if (!status.isOK()) {
LOGV2_FATAL(21746,
"Unable to roll back renameCollection command: {status}",
"status"_attr = status.toString());
throw RSFatalException("Unable to rollback renameCollection command");
}
LOGV2_DEBUG(21680,
1,
"Renamed collection with UUID: {uuid}, from: {renameFrom}, to: {renameTo}",
"uuid"_attr = uuid,
"renameFrom"_attr = info.renameFrom,
"renameTo"_attr = info.renameTo);
}
Status _syncRollback(OperationContext* opCtx,
const OplogInterface& localOplog,
const RollbackSource& rollbackSource,
const IndexBuilds& abortedIndexBuilds,
int requiredRBID,
ReplicationCoordinator* replCoord,
ReplicationProcess* replicationProcess) {
invariant(!opCtx->lockState()->isLocked());
FixUpInfo how;
how.localTopOfOplog = replCoord->getMyLastAppliedOpTime();
LOGV2_OPTIONS(21681,
{logv2::LogTag::kRS},
"Starting rollback. Sync source: {rollbackSource}",
"rollbackSource"_attr = rollbackSource.getSource());
how.rbid = rollbackSource.getRollbackId();
uassert(
40506, "Upstream node rolled back. Need to retry our rollback.", how.rbid == requiredRBID);
// Find the UUID of the transactions collection. An OperationContext is required because the
// UUID is not known at compile time, so the SessionCatalog needs to load the collection.
how.transactionTableUUID = MongoDSessionCatalog::getTransactionTableUUID(opCtx);
// Populate the initial list of index builds to restart with the builds that were aborted due to
// rollback. They may need to be restarted if no associated oplog entries are rolled-back, or
// they may be made redundant by a rolled-back startIndexBuild oplog entry.
how.indexBuildsToRestart.insert(abortedIndexBuilds.begin(), abortedIndexBuilds.end());
LOGV2(21682, "Finding the Common Point");
try {
auto processOperationForFixUp = [&how, &opCtx, &localOplog](const BSONObj& operation) {
return updateFixUpInfoFromLocalOplogEntry(opCtx, localOplog, how, operation, false);
};
// Calls syncRollBackLocalOperations to run updateFixUpInfoFromLocalOplogEntry
// on each oplog entry up until the common point.
auto res = syncRollBackLocalOperations(
localOplog, rollbackSource.getOplog(), processOperationForFixUp);
if (!res.isOK()) {
const auto status = res.getStatus();
switch (status.code()) {
case ErrorCodes::OplogStartMissing:
case ErrorCodes::UnrecoverableRollbackError:
return status;
default:
throw RSFatalException(status.toString());
}
}
how.commonPoint = res.getValue().getOpTime();
how.commonPointOurDiskloc = res.getValue().getRecordId();
how.removeRedundantOperations();
} catch (const RSFatalException& e) {
return Status(ErrorCodes::UnrecoverableRollbackError,
str::stream()
<< "need to rollback, but unable to determine common point between"
" local and remote oplog: "
<< e.what());
}
OpTime commonPoint = how.commonPoint;
OpTime lastCommittedOpTime = replCoord->getLastCommittedOpTime();
OpTime committedSnapshot = replCoord->getCurrentCommittedSnapshotOpTime();
LOGV2(21683, "Rollback common point is {commonPoint}", "commonPoint"_attr = commonPoint);
// Rollback common point should be >= the replication commit point.
invariant(commonPoint.getTimestamp() >= lastCommittedOpTime.getTimestamp());
invariant(commonPoint >= lastCommittedOpTime);
// Rollback common point should be >= the committed snapshot optime.
invariant(commonPoint.getTimestamp() >= committedSnapshot.getTimestamp());
invariant(commonPoint >= committedSnapshot);
try {
// It is always safe to increment the rollback ID first, even if we fail to complete
// the rollback.
auto status = replicationProcess->incrementRollbackID(opCtx);
fassert(40497, status);
syncFixUp(opCtx, how, rollbackSource, replCoord, replicationProcess);
if (MONGO_unlikely(rollbackExitEarlyAfterCollectionDrop.shouldFail())) {
LOGV2(21684,
"rollbackExitEarlyAfterCollectionDrop fail point enabled. Returning early "
"until fail point is disabled.");
return Status(ErrorCodes::NamespaceNotFound,
str::stream() << "Failing rollback because "
"rollbackExitEarlyAfterCollectionDrop fail point "
"enabled.");
}
} catch (const RSFatalException& e) {
return Status(ErrorCodes::UnrecoverableRollbackError, e.what());
} catch (const DBException& e) {
// If we encounter an error during rollback, but we aborted index builds beforehand, we
// will be unable to successfully perform any more rollback attempts. The knowledge of these
// aborted index builds gets lost after the first attempt.
if (abortedIndexBuilds.size()) {
return Status{ErrorCodes::UnrecoverableRollbackError,
"Index builds aborted prior to rollback cannot be restarted by "
"subsequent rollback attempts"}
.withContext(e.what());
}
throw;
}
if (MONGO_unlikely(rollbackHangBeforeFinish.shouldFail())) {
// This log output is used in js tests so please leave it.
LOGV2(21685,
"rollback - rollbackHangBeforeFinish fail point "
"enabled. Blocking until fail point is disabled.");
while (MONGO_unlikely(rollbackHangBeforeFinish.shouldFail())) {
invariant(!globalInShutdownDeprecated()); // It is an error to shutdown while enabled.
mongo::sleepsecs(1);
}
}
return Status::OK();
}
} // namespace
void rollback_internal::syncFixUp(OperationContext* opCtx,
const FixUpInfo& fixUpInfo,
const RollbackSource& rollbackSource,
ReplicationCoordinator* replCoord,
ReplicationProcess* replicationProcess) {
unsigned long long totalSize = 0;
// UUID -> doc id -> doc
stdx::unordered_map<UUID, std::map<DocID, BSONObj>, UUID::Hash> goodVersions;
auto& catalog = CollectionCatalog::get(opCtx);
// Fetches all the goodVersions of each document from the current sync source.
unsigned long long numFetched = 0;
LOGV2(21686, "Starting refetching documents");
for (auto&& doc : fixUpInfo.docsToRefetch) {
invariant(!doc._id.eoo()); // This is checked when we insert to the set.
UUID uuid = doc.uuid;
boost::optional<NamespaceString> nss = catalog.lookupNSSByUUID(opCtx, uuid);
try {
if (nss) {
LOGV2_DEBUG(21687,
2,
"Refetching document, collection: {ns}, UUID: {uuid}, {doc_id}",
"ns"_attr = *nss,
"uuid"_attr = uuid,
"doc_id"_attr = redact(doc._id));
} else {
LOGV2_DEBUG(21688,
2,
"Refetching document, UUID: {uuid}, {doc_id}",
"uuid"_attr = uuid,
"doc_id"_attr = redact(doc._id));
}
// TODO : Slow. Lots of round trips.
numFetched++;
BSONObj good;
NamespaceString resNss;
std::string dbName = nss ? nss->db().toString() : "";
std::tie(good, resNss) = rollbackSource.findOneByUUID(dbName, uuid, doc._id.wrap());
// To prevent inconsistencies in the transactions collection, rollback fails if the UUID
// of the collection is different on the sync source than on the node rolling back,
// forcing an initial sync. This is detected if the returned namespace for a refetch of
// a transaction table document is not "config.transactions," which implies a rename or
// drop of the collection occured on either node.
if (uuid == fixUpInfo.transactionTableUUID &&
resNss != NamespaceString::kSessionTransactionsTableNamespace) {
throw RSFatalException(
str::stream()
<< "A fetch on the transactions collection returned an unexpected namespace: "
<< resNss.ns()
<< ". The transactions collection cannot be correctly rolled back, a full "
"resync is required.");
}
totalSize += good.objsize();
// Checks that the total amount of data that needs to be refetched is at most
// 300 MB. We do not roll back more than 300 MB of documents in order to
// prevent out of memory errors from too much data being stored. See SERVER-23392.
if (totalSize >= 300 * 1024 * 1024) {
throw RSFatalException("replSet too much data to roll back.");
}
// Note good might be empty, indicating we should delete it.
goodVersions[uuid].insert(std::pair<DocID, BSONObj>(doc, good));
} catch (const DBException& ex) {
// If the collection turned into a view, we might get an error trying to
// refetch documents, but these errors should be ignored, as we'll be creating
// the view during oplog replay.
// Collection may be dropped on the sync source, in which case it will be dropped during
// oplog replay. So it is safe to ignore NamespaceNotFound errors while trying to
// refetch documents.
if (ex.code() == ErrorCodes::CommandNotSupportedOnView ||
ex.code() == ErrorCodes::NamespaceNotFound)
continue;
LOGV2(21689,
"Rollback couldn't re-fetch from uuid: {uuid} _id: {doc_id} "
"{numFetched}/{docsToRefetch}: {ex}",
"uuid"_attr = uuid,
"doc_id"_attr = redact(doc._id),
"numFetched"_attr = numFetched,
"docsToRefetch"_attr = fixUpInfo.docsToRefetch.size(),
"ex"_attr = redact(ex));
throw;
}
}
LOGV2(21690,
"Finished refetching documents. Total size of documents refetched: {size}",
"size"_attr = goodVersions.size());
// We must start taking unstable checkpoints before rolling back oplog entries. Otherwise, a
// stable checkpoint could include the fixup write (since it is untimestamped) but not the write
// being rolled back (if it is after the stable timestamp), leading to inconsistent state. An
// unstable checkpoint will include both writes.
if (!serverGlobalParams.enableMajorityReadConcern) {
LOGV2(21691,
"Setting initialDataTimestamp to 0 so that we start taking unstable checkpoints.");
opCtx->getServiceContext()->getStorageEngine()->setInitialDataTimestamp(
Timestamp::kAllowUnstableCheckpointsSentinel);
}
LOGV2(21692, "Checking the RollbackID and updating the MinValid if necessary");
checkRbidAndUpdateMinValid(opCtx, fixUpInfo.rbid, rollbackSource, replicationProcess);
invariant(!fixUpInfo.commonPointOurDiskloc.isNull());
// Rolls back createIndexes commands by dropping the indexes that were created. It is
// necessary to roll back createIndexes commands before dropIndexes commands because
// it is possible that we previously dropped an index with the same name but a different
// index spec. If we attempt to re-create an index that has the same name as an existing
// index, the operation will fail. Thus, we roll back createIndexes commands first in
// order to ensure that no collisions will occur when we re-create previously dropped
// indexes.
// We drop indexes before renaming collections so that if a collection name gets longer,
// any indexes with names that are now too long will already be dropped.
LOGV2(21693, "Rolling back createIndexes and startIndexBuild operations");
for (auto it = fixUpInfo.indexesToDrop.begin(); it != fixUpInfo.indexesToDrop.end(); it++) {
UUID uuid = it->first;
std::set<std::string> indexNames = it->second;
rollbackCreateIndexes(opCtx, uuid, indexNames);
}
// Drop any unfinished indexes. These are indexes where the startIndexBuild oplog entry was
// rolled-back, but the unfinished index still exists in the catalog. Drop these before any
// collection drops, because one of the preconditions of dropping a collection is that there are
// no unfinished indxes.
LOGV2(21694, "Rolling back unfinished startIndexBuild operations");
for (auto index : fixUpInfo.unfinishedIndexesToDrop) {
UUID uuid = index.first;
std::set<std::string> indexNames = index.second;
rollbackCreateIndexes(opCtx, uuid, indexNames);
}
LOGV2(21695, "Dropping collections to roll back create operations");
// Drops collections before updating individual documents. We drop these collections before
// rolling back any other commands to prevent namespace collisions that may occur
// when undoing renameCollection operations.
for (auto uuid : fixUpInfo.collectionsToDrop) {
// Checks that if the collection is going to be dropped, all commands that
// were done on the collection to be dropped were removed during the function
// call to removeRedundantOperations().
invariant(!fixUpInfo.indexesToDrop.count(uuid));
invariant(!fixUpInfo.indexesToCreate.count(uuid));
invariant(!fixUpInfo.collectionsToRename.count(uuid));
invariant(!fixUpInfo.collectionsToResyncMetadata.count(uuid));
invariant(!std::any_of(fixUpInfo.indexBuildsToRestart.begin(),
fixUpInfo.indexBuildsToRestart.end(),
[&](auto build) { return build.second.collUUID == uuid; }));
boost::optional<NamespaceString> nss =
CollectionCatalog::get(opCtx).lookupNSSByUUID(opCtx, uuid);
// Do not attempt to acquire the database lock with an empty namespace. We should survive
// an attempt to drop a non-existent collection.
if (!nss) {
LOGV2(21696, "This collection does not exist, UUID: {uuid}", "uuid"_attr = uuid);
} else {
LOGV2(21697,
"Dropping collection: {ns}, UUID: {uuid}",
"ns"_attr = *nss,
"uuid"_attr = uuid);
AutoGetDb dbLock(opCtx, nss->db(), MODE_X);
Database* db = dbLock.getDb();
if (db) {
Collection* collection =
CollectionCatalog::get(opCtx).lookupCollectionByUUID(opCtx, uuid);
dropCollection(opCtx, *nss, collection, db);
LOGV2_DEBUG(21698,
1,
"Dropped collection: {ns}, UUID: {uuid}",
"ns"_attr = *nss,
"uuid"_attr = uuid);
}
}
}
if (MONGO_unlikely(rollbackExitEarlyAfterCollectionDrop.shouldFail())) {
return;
}
// Rolling back renameCollection commands.
LOGV2(21699, "Rolling back renameCollection commands and collection drop commands.");
for (auto it = fixUpInfo.collectionsToRename.begin(); it != fixUpInfo.collectionsToRename.end();
it++) {
UUID uuid = it->first;
RenameCollectionInfo info = it->second;
rollbackRenameCollection(opCtx, uuid, info);
}
LOGV2(21700,
"Rolling back collections pending being dropped: Removing them from the list of "
"drop-pending collections in the DropPendingCollectionReaper.");
// Roll back any drop-pending collections. This must be done first so that the collection
// exists when we attempt to resync its metadata or insert documents into it.
for (const auto& collPair : fixUpInfo.collectionsToRemoveFromDropPendingCollections) {
const auto& optime = collPair.second.first;
const auto& collectionNamespace = collPair.second.second;
LOGV2_DEBUG(21701,
1,
"Rolling back collection pending being dropped for OpTime: {optime}, "
"collection: {collectionNamespace}",
"optime"_attr = optime,
"collectionNamespace"_attr = collectionNamespace);
DropPendingCollectionReaper::get(opCtx)->rollBackDropPendingCollection(
opCtx, optime, collectionNamespace);
}
// Full collection data and metadata resync.
if (!fixUpInfo.collectionsToResyncMetadata.empty()) {
// Retrieves collections from the sync source in order to obtain the collection
// flags needed to roll back collMod operations. We roll back collMod operations
// after create/renameCollection/drop commands in order to ensure that the
// collections that we want to change actually exist. For example, if a collMod
// occurs and then the collection is dropped. If we do not first re-create the
// collection, we will not be able to retrieve the collection's catalog entries.
for (auto uuid : fixUpInfo.collectionsToResyncMetadata) {
boost::optional<NamespaceString> nss =
CollectionCatalog::get(opCtx).lookupNSSByUUID(opCtx, uuid);
invariant(nss);
LOGV2(21702,
"Resyncing collection metadata for collection: {ns}, UUID: {uuid}",
"ns"_attr = *nss,
"uuid"_attr = uuid);
Lock::DBLock dbLock(opCtx, nss->db(), MODE_X);
auto databaseHolder = DatabaseHolder::get(opCtx);
auto db = databaseHolder->openDb(opCtx, nss->db().toString());
invariant(db);
Collection* collection =
CollectionCatalog::get(opCtx).lookupCollectionByUUID(opCtx, uuid);
invariant(collection);
auto infoResult = rollbackSource.getCollectionInfoByUUID(nss->db().toString(), uuid);
if (!infoResult.isOK()) {
// The collection was dropped by the sync source so we can't correctly change it
// here. If we get to the roll-forward phase, we will drop it then. If the drop
// is rolled back upstream and we restart, we expect to still have the
// collection.
LOGV2(21703,
"{ns} not found on remote host, so we do not roll back collmod "
"operation. Instead, we will drop the collection soon.",
"ns"_attr = nss->ns());
continue;
}
auto info = infoResult.getValue();
CollectionOptions options;
// Updates the collection flags.
if (auto optionsField = info["options"]) {
if (optionsField.type() != Object) {
throw RSFatalException(str::stream()
<< "Failed to parse options " << info
<< ": expected 'options' to be an "
<< "Object, got " << typeName(optionsField.type()));
}
auto statusWithCollectionOptions = CollectionOptions::parse(
optionsField.Obj(), CollectionOptions::parseForCommand);
if (!statusWithCollectionOptions.isOK()) {
throw RSFatalException(str::stream()
<< "Failed to parse options " << info << ": "
<< statusWithCollectionOptions.getStatus().toString());
}
options = statusWithCollectionOptions.getValue();
} else {
// Use default options.
}
WriteUnitOfWork wuow(opCtx);
// Set collection to whatever temp status is on the sync source.
DurableCatalog::get(opCtx)->setIsTemp(opCtx, collection->getCatalogId(), options.temp);
// Set any document validation options. We update the validator fields without
// parsing/validation, since we fetched the options object directly from the sync
// source, and we should set our validation options to match it exactly.
auto validatorStatus = collection->updateValidator(
opCtx, options.validator, options.validationLevel, options.validationAction);
if (!validatorStatus.isOK()) {
throw RSFatalException(str::stream()
<< "Failed to update validator for " << nss->toString()
<< " (" << uuid << ") with " << redact(info)
<< ". Got: " << validatorStatus.toString());
}
wuow.commit();
LOGV2_DEBUG(
21704,
1,
"Resynced collection metadata for collection: {ns}, UUID: {uuid}, with: {info}, "
"to: {catalogId}",
"ns"_attr = *nss,
"uuid"_attr = uuid,
"info"_attr = redact(info),
"catalogId"_attr =
redact(DurableCatalog::get(opCtx)
->getCollectionOptions(opCtx, collection->getCatalogId())
.toBSON()));
}
// Since we read from the sync source to retrieve the metadata of the
// collection, we must check if the sync source rolled back as well as update
// minValid if necessary.
LOGV2(21705, "Rechecking the Rollback ID and minValid");
checkRbidAndUpdateMinValid(opCtx, fixUpInfo.rbid, rollbackSource, replicationProcess);
}
// Rolls back dropIndexes commands by re-creating the indexes that were dropped.
LOGV2(21706, "Rolling back dropIndexes commands.");
for (auto it = fixUpInfo.indexesToCreate.begin(); it != fixUpInfo.indexesToCreate.end(); it++) {
UUID uuid = it->first;
std::map<std::string, BSONObj> indexNames = it->second;
rollbackDropIndexes(opCtx, uuid, indexNames);
}
LOGV2(21707, "Restarting rolled-back committed or aborted index builds.");
IndexBuildsCoordinator::get(opCtx)->restartIndexBuildsForRecovery(
opCtx, fixUpInfo.indexBuildsToRestart);
LOGV2(21708,
"Deleting and updating documents to roll back insert, update and remove "
"operations");
unsigned deletes = 0, updates = 0;
time_t lastProgressUpdate = time(nullptr);
time_t progressUpdateGap = 10;
for (const auto& nsAndGoodVersionsByDocID : goodVersions) {
// Keeps an archive of items rolled back if the collection has not been dropped
// while rolling back createCollection operations.
const auto& uuid = nsAndGoodVersionsByDocID.first;
unique_ptr<RemoveSaver> removeSaver;
invariant(!fixUpInfo.collectionsToDrop.count(uuid));
boost::optional<NamespaceString> nss = catalog.lookupNSSByUUID(opCtx, uuid);
if (!nss) {
nss = NamespaceString();
}
if (RollbackImpl::shouldCreateDataFiles()) {
removeSaver = std::make_unique<RemoveSaver>("rollback", "", uuid.toString());
LOGV2(21709,
"Preparing to write deleted documents to a rollback file for collection {ns} "
"with uuid {uuid} to {file}",
"ns"_attr = *nss,
"uuid"_attr = uuid.toString(),
"file"_attr = removeSaver->file().generic_string());
}
const auto& goodVersionsByDocID = nsAndGoodVersionsByDocID.second;
for (const auto& idAndDoc : goodVersionsByDocID) {
time_t now = time(nullptr);
if (now - lastProgressUpdate > progressUpdateGap) {
LOGV2(21710,
"{deletes} delete and {updates} update operations processed out of "
"{total} total operations.",
"deletes"_attr = deletes,
"updates"_attr = updates,
"total"_attr = goodVersions.size());
lastProgressUpdate = now;
}
const DocID& doc = idAndDoc.first;
BSONObj pattern = doc._id.wrap(); // { _id : ... }
try {
// TODO: Lots of overhead in context. This can be faster.
const NamespaceString docNss(doc.ns);
Lock::DBLock docDbLock(opCtx, docNss.db(), MODE_X);
OldClientContext ctx(opCtx, doc.ns.toString());
Collection* collection = catalog.lookupCollectionByUUID(opCtx, uuid);
// Adds the doc to our rollback file if the collection was not dropped while
// rolling back createCollection operations. Does not log an error when
// undoing an insert on a no longer existing collection. It is likely that
// the collection was dropped as part of rolling back a createCollection
// command and the document no longer exists.
if (collection && removeSaver) {
BSONObj obj;
bool found = Helpers::findOne(opCtx, collection, pattern, obj, false);
if (found) {
auto status = removeSaver->goingToDelete(obj);
if (!status.isOK()) {
LOGV2_FATAL(21747,
"Rollback cannot write document in namespace {ns} to "
"archive file: {status}",
"ns"_attr = nss->ns(),
"status"_attr = redact(status));
throw RSFatalException(str::stream()
<< "Rollback cannot write document in namespace "
<< nss->ns() << " to archive file.");
}
} else {
LOGV2_ERROR(21730,
"Rollback cannot find object: {pattern} in namespace {ns}",
"pattern"_attr = pattern,
"ns"_attr = nss->ns());
}
}
if (idAndDoc.second.isEmpty()) {
LOGV2_DEBUG(21711,
2,
"Deleting document with: {doc_id}, from collection: {ns}, with "
"UUID: {uuid}",
"doc_id"_attr = redact(doc._id),
"ns"_attr = doc.ns,
"uuid"_attr = uuid);
// If the document could not be found on the primary, deletes the document.
// TODO 1.6 : can't delete from a capped collection. Need to handle that
// here.
deletes++;
if (collection) {
if (collection->isCapped()) {
// Can't delete from a capped collection - so we truncate instead.
// if this item must go, so must all successors.
try {
// TODO: IIRC cappedTruncateAfter does not handle completely
// empty. This will be slow if there is no _id index in
// the collection.
const auto clock = opCtx->getServiceContext()->getFastClockSource();
const auto findOneStart = clock->now();
RecordId loc = Helpers::findOne(opCtx, collection, pattern, false);
if (clock->now() - findOneStart > Milliseconds(200))
LOGV2_WARNING(21726,
"Roll back slow no _id index for {ns} perhaps?",
"ns"_attr = nss->ns());
// Would be faster but requires index:
// RecordId loc = Helpers::findById(nsd, pattern);
if (!loc.isNull()) {
try {
writeConflictRetry(opCtx,
"cappedTruncateAfter",
collection->ns().ns(),
[&] {
WriteUnitOfWork wunit(opCtx);
collection->cappedTruncateAfter(
opCtx, loc, true);
wunit.commit();
});
} catch (const DBException& e) {
if (e.code() == 13415) {
// hack: need to just make cappedTruncate do this...
writeConflictRetry(
opCtx, "truncate", collection->ns().ns(), [&] {
WriteUnitOfWork wunit(opCtx);
uassertStatusOK(collection->truncate(opCtx));
wunit.commit();
});
} else {
throw;
}
}
}
} catch (const DBException& e) {
// Replicated capped collections have many ways to become
// inconsistent. We rely on age-out to make these problems go away
// eventually.
LOGV2_WARNING(21727,
"Ignoring failure to roll back change to capped "
"collection {ns} with _id "
"{_id}: {e}",
"ns"_attr = nss->ns(),
"_id"_attr = redact(idAndDoc.first._id.toString(
/*includeFieldName*/ false)),
"e"_attr = redact(e));
}
} else {
deleteObjects(opCtx,
collection,
*nss,
pattern,
true, // justOne
true); // god
}
}
} else {
LOGV2_DEBUG(21712,
2,
"Updating document with: {doc_id}, from collection: {doc_ns}, "
"UUID: {uuid}, to: {doc}",
"doc_id"_attr = redact(doc._id),
"doc_ns"_attr = doc.ns,
"uuid"_attr = uuid,
"doc"_attr = redact(idAndDoc.second));
// TODO faster...
updates++;
UpdateRequest request(*nss);
request.setQuery(pattern);
request.setUpdateModification(idAndDoc.second);
request.setGod();
request.setUpsert();
update(opCtx, ctx.db(), request);
}
} catch (const DBException& e) {
LOGV2(21713,
"Exception in rollback ns:{ns} {pattern} {e} ndeletes:{deletes}",
"ns"_attr = nss->ns(),
"pattern"_attr = pattern.toString(),
"e"_attr = redact(e),
"deletes"_attr = deletes);
throw;
}
}
}
LOGV2(21714,
"Rollback deleted {deletes} documents and updated {updates} documents.",
"deletes"_attr = deletes,
"updates"_attr = updates);
if (!serverGlobalParams.enableMajorityReadConcern) {
// When majority read concern is disabled, the stable timestamp may be ahead of the common
// point. Force the stable timestamp back to the common point, to allow writes after the
// common point.
const bool force = true;
LOGV2(21715,
"Forcing the stable timestamp to the common point: "
"{commonPoint}",
"commonPoint"_attr = fixUpInfo.commonPoint.getTimestamp());
opCtx->getServiceContext()->getStorageEngine()->setStableTimestamp(
fixUpInfo.commonPoint.getTimestamp(), force);
// We must not take a stable checkpoint until it is guaranteed to include all writes from
// before the rollback (i.e. the stable timestamp is at least the local top of oplog). In
// addition, we must not take a stable checkpoint until the stable timestamp reaches the
// sync source top of oplog (minValid), since we must not take a stable checkpoint until we
// are in a consistent state. We control this by seting the initialDataTimestamp to the
// maximum of these two values. No checkpoints are taken until stable timestamp >=
// initialDataTimestamp.
auto syncSourceTopOfOplog = OpTime::parseFromOplogEntry(rollbackSource.getLastOperation())
.getValue()
.getTimestamp();
LOGV2(21716,
"Setting initialDataTimestamp to the max of local top of oplog and sync source "
"top of oplog. Local top of oplog: {localTopOfOplog}, sync "
"source top of oplog: {syncSourceTopOfOplog}",
"localTopOfOplog"_attr = fixUpInfo.localTopOfOplog.getTimestamp(),
"syncSourceTopOfOplog"_attr = syncSourceTopOfOplog);
opCtx->getServiceContext()->getStorageEngine()->setInitialDataTimestamp(
std::max(fixUpInfo.localTopOfOplog.getTimestamp(), syncSourceTopOfOplog));
// Take an unstable checkpoint to ensure that all of the writes performed during rollback
// are persisted to disk before truncating oplog.
LOGV2(21717, "Waiting for an unstable checkpoint");
const bool stableCheckpoint = false;
opCtx->recoveryUnit()->waitUntilUnjournaledWritesDurable(opCtx, stableCheckpoint);
}
LOGV2(21718,
"Truncating the oplog at {commonPoint} ({commonPointOurDiskloc}), "
"non-inclusive",
"commonPoint"_attr = fixUpInfo.commonPoint.toString(),
"commonPointOurDiskloc"_attr = fixUpInfo.commonPointOurDiskloc);
// Cleans up the oplog.
{
const NamespaceString oplogNss(NamespaceString::kRsOplogNamespace);
Lock::DBLock oplogDbLock(opCtx, oplogNss.db(), MODE_IX);
Lock::CollectionLock oplogCollectionLoc(opCtx, oplogNss, MODE_X);
OldClientContext ctx(opCtx, oplogNss.ns());
Collection* oplogCollection =
CollectionCatalog::get(opCtx).lookupCollectionByNamespace(opCtx, oplogNss);
if (!oplogCollection) {
fassertFailedWithStatusNoTrace(
40495,
Status(ErrorCodes::UnrecoverableRollbackError,
str::stream() << "Can't find " << NamespaceString::kRsOplogNamespace.ns()));
}
// TODO: fatal error if this throws?
oplogCollection->cappedTruncateAfter(opCtx, fixUpInfo.commonPointOurDiskloc, false);
}
if (!serverGlobalParams.enableMajorityReadConcern) {
// If the server crashes and restarts before a stable checkpoint is taken, it will restart
// from the unstable checkpoint taken at the end of rollback. To ensure replication recovery
// replays all oplog after the common point, we set the appliedThrough to the common point.
// This is done using an untimestamped write, since timestamping the write with the common
// point TS would be incorrect (since this is equal to the stable timestamp), and this write
// will be included in the unstable checkpoint regardless of its timestamp.
LOGV2(21719,
"Setting appliedThrough to the common point: {commonPoint}",
"commonPoint"_attr = fixUpInfo.commonPoint);
const bool setTimestamp = false;
replicationProcess->getConsistencyMarkers()->setAppliedThrough(
opCtx, fixUpInfo.commonPoint, setTimestamp);
// Take an unstable checkpoint to ensure the appliedThrough write is persisted to disk.
LOGV2(21720, "Waiting for an unstable checkpoint");
const bool stableCheckpoint = false;
opCtx->recoveryUnit()->waitUntilUnjournaledWritesDurable(opCtx, stableCheckpoint);
// Ensure that appliedThrough is unset in the next stable checkpoint.
LOGV2(21721, "Clearing appliedThrough");
replicationProcess->getConsistencyMarkers()->clearAppliedThrough(opCtx, Timestamp());
}
Status status = AuthorizationManager::get(opCtx->getServiceContext())->initialize(opCtx);
if (!status.isOK()) {
LOGV2_FATAL(21748,
"Failed to reinitialize auth data after rollback: {status}",
"status"_attr = redact(status));
fassertFailedNoTrace(40496);
}
// If necessary, clear the memory of existing sessions.
if (fixUpInfo.refetchTransactionDocs) {
MongoDSessionCatalog::invalidateAllSessions(opCtx);
}
if (auto validator = LogicalTimeValidator::get(opCtx)) {
validator->resetKeyManagerCache();
}
// Force the config server to update its shard registry on next access. Otherwise it may have
// the stale data that has been just rolled back.
if (serverGlobalParams.clusterRole == ClusterRole::ConfigServer) {
if (auto shardRegistry = Grid::get(opCtx)->shardRegistry()) {
shardRegistry->clearEntries();
}
}
// Force the default read/write concern cache to reload on next access in case the defaults
// document was rolled back.
ReadWriteConcernDefaults::get(opCtx).invalidate();
// Reload the lastAppliedOpTime and lastDurableOpTime value in the replcoord and the
// lastApplied value in bgsync to reflect our new last op. The rollback common point does
// not necessarily represent a consistent database state. For example, on a secondary, we may
// have rolled back to an optime that fell in the middle of an oplog application batch. We make
// the database consistent again after rollback by applying ops forward until we reach
// 'minValid'.
replCoord->resetLastOpTimesFromOplog(opCtx,
ReplicationCoordinator::DataConsistency::Inconsistent);
}
Status syncRollback(OperationContext* opCtx,
const OplogInterface& localOplog,
const RollbackSource& rollbackSource,
const IndexBuilds& abortedIndexBuilds,
int requiredRBID,
ReplicationCoordinator* replCoord,
ReplicationProcess* replicationProcess) {
invariant(opCtx);
invariant(replCoord);
DisableDocumentValidation validationDisabler(opCtx);
UnreplicatedWritesBlock replicationDisabler(opCtx);
Status status = _syncRollback(opCtx,
localOplog,
rollbackSource,
abortedIndexBuilds,
requiredRBID,
replCoord,
replicationProcess);
LOGV2_OPTIONS(21722,
{logv2::LogTag::kRS},
"Rollback finished. The final minValid is: "
"{minValid}",
"minValid"_attr =
replicationProcess->getConsistencyMarkers()->getMinValid(opCtx));
return status;
}
void rollback(OperationContext* opCtx,
const OplogInterface& localOplog,
const RollbackSource& rollbackSource,
const IndexBuilds& abortedIndexBuilds,
int requiredRBID,
ReplicationCoordinator* replCoord,
ReplicationProcess* replicationProcess,
std::function<void(int)> sleepSecsFn) {
// Set state to ROLLBACK while we are in this function. This prevents serving reads, even from
// the oplog. This can fail if we are elected PRIMARY, in which case we better not do any
// rolling back. If we successfully enter ROLLBACK we will only exit this function fatally or
// after transitioning to RECOVERING. We always transition to RECOVERING regardless of success
// or (recoverable) failure since we may be in an inconsistent state. If rollback failed before
// writing anything, the Replication Coordinator will quickly take us to SECONDARY since we are
// still at our original MinValid, which is fine because we may choose a sync source that
// doesn't require rollback. If it failed after we wrote to MinValid, then we will pick a sync
// source that will cause us to roll back to the same common point, which is fine. If we
// succeeded, we will be consistent as soon as we apply up to/through MinValid and the
// Replication Coordinator will make us SECONDARY then.
{
ReplicationStateTransitionLockGuard transitionGuard(opCtx, MODE_X);
auto status = replCoord->setFollowerModeStrict(opCtx, MemberState::RS_ROLLBACK);
if (!status.isOK()) {
LOGV2(21723,
"Cannot transition from {memberState} to "
"{targetState}{status}",
"memberState"_attr = replCoord->getMemberState().toString(),
"targetState"_attr = MemberState(MemberState::RS_ROLLBACK).toString(),
"status"_attr = causedBy(status));
return;
}
}
if (MONGO_unlikely(rollbackHangAfterTransitionToRollback.shouldFail())) {
LOGV2(21724,
"rollbackHangAfterTransitionToRollback fail point enabled. Blocking until fail "
"point is disabled (rs_rollback).");
rollbackHangAfterTransitionToRollback.pauseWhileSet(opCtx);
}
try {
auto status = syncRollback(opCtx,
localOplog,
rollbackSource,
abortedIndexBuilds,
requiredRBID,
replCoord,
replicationProcess);
// Aborts only when syncRollback detects we are in a unrecoverable state.
// WARNING: these statuses sometimes have location codes which are lost with uassertStatusOK
// so we need to check here first.
if (ErrorCodes::UnrecoverableRollbackError == status.code()) {
LOGV2_FATAL(21749,
"Unable to complete rollback. A full resync may be needed: {status}",
"status"_attr = redact(status));
fassertFailedNoTrace(40507);
}
// In other cases, we log the message contained in the error status and retry later.
uassertStatusOK(status);
} catch (const DBException& ex) {
// UnrecoverableRollbackError should only come from a returned status which is handled
// above.
invariant(ex.code() != ErrorCodes::UnrecoverableRollbackError);
LOGV2_WARNING(21728,
"Rollback cannot complete at this time (retrying later): {ex} "
"appliedThrough= {myLastAppliedOpTime} minvalid= "
"{minValid}",
"ex"_attr = redact(ex),
"myLastAppliedOpTime"_attr = replCoord->getMyLastAppliedOpTime(),
"minValid"_attr =
replicationProcess->getConsistencyMarkers()->getMinValid(opCtx));
// Sleep a bit to allow upstream node to coalesce, if that was the cause of the failure. If
// we failed in a way that will keep failing, but wasn't flagged as a fatal failure, this
// will also prevent us from hot-looping and putting too much load on upstream nodes.
sleepSecsFn(5); // 5 seconds was chosen as a completely arbitrary amount of time.
} catch (...) {
std::terminate();
}
// At this point we are about to leave rollback. Before we do, wait for any writes done
// as part of rollback to be durable, and then do any necessary checks that we didn't
// wind up rolling back something illegal. We must wait for the rollback to be durable
// so that if we wind up shutting down uncleanly in response to something we rolled back
// we know that we won't wind up right back in the same situation when we start back up
// because the rollback wasn't durable.
opCtx->recoveryUnit()->waitUntilDurable(opCtx);
// If we detected that we rolled back the shardIdentity document as part of this rollback
// then we must shut down to clear the in-memory ShardingState associated with the
// shardIdentity document.
if (ShardIdentityRollbackNotifier::get(opCtx)->didRollbackHappen()) {
LOGV2_FATAL(21750,
"shardIdentity document rollback detected. Shutting down to clear "
"in-memory sharding state. Restarting this process should safely return it "
"to a healthy state");
fassertFailedNoTrace(40498);
}
auto status = replCoord->setFollowerMode(MemberState::RS_RECOVERING);
if (!status.isOK()) {
LOGV2_FATAL(21751,
"Failed to transition into {targetState}; expected to be in "
"state {expectedState}; found self in "
"{actualState}{status}",
"targetState"_attr = MemberState(MemberState::RS_RECOVERING),
"expectedState"_attr = MemberState(MemberState::RS_ROLLBACK),
"actualState"_attr = replCoord->getMemberState(),
"status"_attr = causedBy(status));
fassertFailedNoTrace(40499);
}
}
} // namespace repl
} // namespace mongo
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