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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::kSharding
#include "mongo/platform/basic.h"
#include "mongo/db/s/migration_chunk_cloner_source_legacy.h"
#include "mongo/base/status.h"
#include "mongo/client/read_preference.h"
#include "mongo/db/catalog/index_catalog.h"
#include "mongo/db/catalog_raii.h"
#include "mongo/db/dbhelpers.h"
#include "mongo/db/exec/working_set_common.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/query/internal_plans.h"
#include "mongo/db/repl/optime.h"
#include "mongo/db/repl/replication_process.h"
#include "mongo/db/s/collection_sharding_runtime.h"
#include "mongo/db/s/migration_source_manager.h"
#include "mongo/db/s/sharding_statistics.h"
#include "mongo/db/s/start_chunk_clone_request.h"
#include "mongo/db/service_context.h"
#include "mongo/executor/remote_command_request.h"
#include "mongo/executor/remote_command_response.h"
#include "mongo/executor/task_executor.h"
#include "mongo/executor/task_executor_pool.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/s/client/shard_registry.h"
#include "mongo/s/grid.h"
#include "mongo/util/elapsed_tracker.h"
#include "mongo/util/log.h"
#include "mongo/util/scopeguard.h"
#include "mongo/util/str.h"
#include "mongo/util/time_support.h"
namespace mongo {
namespace {
const char kRecvChunkStatus[] = "_recvChunkStatus";
const char kRecvChunkCommit[] = "_recvChunkCommit";
const char kRecvChunkAbort[] = "_recvChunkAbort";
const int kMaxObjectPerChunk{250000};
bool isInRange(const BSONObj& obj,
const BSONObj& min,
const BSONObj& max,
const ShardKeyPattern& shardKeyPattern) {
BSONObj k = shardKeyPattern.extractShardKeyFromDoc(obj);
return k.woCompare(min) >= 0 && k.woCompare(max) < 0;
}
BSONObj createRequestWithSessionId(StringData commandName,
const NamespaceString& nss,
const MigrationSessionId& sessionId,
bool waitForSteadyOrDone = false) {
BSONObjBuilder builder;
builder.append(commandName, nss.ns());
builder.append("waitForSteadyOrDone", waitForSteadyOrDone);
sessionId.append(&builder);
return builder.obj();
}
const BSONObj& getDocumentKeyFromReplOperation(repl::ReplOperation replOperation,
repl::OpTypeEnum opType) {
switch (opType) {
case repl::OpTypeEnum::kInsert:
case repl::OpTypeEnum::kDelete:
return replOperation.getObject();
case repl::OpTypeEnum::kUpdate:
return *replOperation.getObject2();
default:
MONGO_UNREACHABLE;
}
MONGO_UNREACHABLE;
}
char getOpCharForCrudOpType(repl::OpTypeEnum opType) {
switch (opType) {
case repl::OpTypeEnum::kInsert:
return 'i';
case repl::OpTypeEnum::kUpdate:
return 'u';
case repl::OpTypeEnum::kDelete:
return 'd';
default:
MONGO_UNREACHABLE;
}
MONGO_UNREACHABLE;
}
} // namespace
/**
* Used to commit work for LogOpForSharding. Used to keep track of changes in documents that are
* part of a chunk being migrated.
*/
class LogOpForShardingHandler final : public RecoveryUnit::Change {
public:
/**
* Invariant: idObj should belong to a document that is part of the active chunk being migrated
*/
LogOpForShardingHandler(MigrationChunkClonerSourceLegacy* cloner,
const BSONObj& idObj,
const char op,
const repl::OpTime& opTime,
const repl::OpTime& prePostImageOpTime)
: _cloner(cloner),
_idObj(idObj.getOwned()),
_op(op),
_opTime(opTime),
_prePostImageOpTime(prePostImageOpTime) {}
void commit(boost::optional<Timestamp>) override {
_cloner->_addToTransferModsQueue(_idObj, _op, _opTime, _prePostImageOpTime);
_cloner->_decrementOutstandingOperationTrackRequests();
}
void rollback() override {
_cloner->_decrementOutstandingOperationTrackRequests();
}
private:
MigrationChunkClonerSourceLegacy* const _cloner;
const BSONObj _idObj;
const char _op;
const repl::OpTime _opTime;
const repl::OpTime _prePostImageOpTime;
};
void LogTransactionOperationsForShardingHandler::commit(boost::optional<Timestamp>) {
std::set<NamespaceString> namespacesTouchedByTransaction;
for (const auto& stmt : _stmts) {
const auto& nss = stmt.getNss();
auto csr = CollectionShardingRuntime::get_UNSAFE(_svcCtx, nss);
auto opCtx = cc().getOperationContext();
auto csrLock = CollectionShardingRuntime::CSRLock::lockShared(opCtx, csr);
auto msm = MigrationSourceManager::get(csr, csrLock);
if (!msm) {
continue;
}
auto cloner = dynamic_cast<MigrationChunkClonerSourceLegacy*>(msm->getCloner().get());
auto opType = stmt.getOpType();
auto documentKey = getDocumentKeyFromReplOperation(stmt, opType);
auto idElement = documentKey["_id"];
if (idElement.eoo()) {
warning() << "Received a document with no id, ignoring: " << redact(documentKey);
continue;
}
auto const& minKey = cloner->_args.getMinKey();
auto const& maxKey = cloner->_args.getMaxKey();
auto const& shardKeyPattern = cloner->_shardKeyPattern;
if (!isInRange(documentKey, minKey, maxKey, shardKeyPattern)) {
// If the preImageDoc is not in range but the postImageDoc was, we know that the
// document has changed shard keys and no longer belongs in the chunk being cloned.
// We will model the deletion of the preImage document so that the destination chunk
// does not receive an outdated version of this document.
if (opType == repl::OpTypeEnum::kUpdate &&
isInRange(stmt.getPreImageDocumentKey(), minKey, maxKey, shardKeyPattern) &&
!stmt.getPreImageDocumentKey()["_id"].eoo()) {
opType = repl::OpTypeEnum::kDelete;
idElement = stmt.getPreImageDocumentKey()["id"];
} else {
continue;
}
}
// Inform the session migration subsystem that a transaction has committed for all involved
// namespaces.
if (namespacesTouchedByTransaction.find(nss) == namespacesTouchedByTransaction.end()) {
cloner->_addToSessionMigrationOptimeQueue(
_prepareOrCommitOpTime,
SessionCatalogMigrationSource::EntryAtOpTimeType::kTransaction);
namespacesTouchedByTransaction.emplace(nss);
}
// Pass an empty prePostOpTime to the queue because retryable write history doesn't care
// about writes in transactions.
cloner->_addToTransferModsQueue(idElement.wrap(), getOpCharForCrudOpType(opType), {}, {});
}
}
MigrationChunkClonerSourceLegacy::MigrationChunkClonerSourceLegacy(MoveChunkRequest request,
const BSONObj& shardKeyPattern,
ConnectionString donorConnStr,
HostAndPort recipientHost)
: _args(std::move(request)),
_shardKeyPattern(shardKeyPattern),
_sessionId(MigrationSessionId::generate(_args.getFromShardId().toString(),
_args.getToShardId().toString())),
_donorConnStr(std::move(donorConnStr)),
_recipientHost(std::move(recipientHost)) {}
MigrationChunkClonerSourceLegacy::~MigrationChunkClonerSourceLegacy() {
invariant(_state == kDone);
}
Status MigrationChunkClonerSourceLegacy::startClone(OperationContext* opCtx) {
invariant(_state == kNew);
invariant(!opCtx->lockState()->isLocked());
auto const replCoord = repl::ReplicationCoordinator::get(opCtx);
if (replCoord->getReplicationMode() == repl::ReplicationCoordinator::modeReplSet) {
_sessionCatalogSource = std::make_unique<SessionCatalogMigrationSource>(
opCtx,
_args.getNss(),
ChunkRange(_args.getMinKey(), _args.getMaxKey()),
_shardKeyPattern.getKeyPattern());
// Prime up the session migration source if there are oplog entries to migrate.
_sessionCatalogSource->fetchNextOplog(opCtx);
}
{
// Ignore prepare conflicts when we load ids of currently available documents. This is
// acceptable because we will track changes made by prepared transactions at transaction
// commit time.
auto originalPrepareConflictBehavior = opCtx->recoveryUnit()->getPrepareConflictBehavior();
ON_BLOCK_EXIT([&] {
opCtx->recoveryUnit()->setPrepareConflictBehavior(originalPrepareConflictBehavior);
});
opCtx->recoveryUnit()->setPrepareConflictBehavior(
PrepareConflictBehavior::kIgnoreConflicts);
auto storeCurrentLocsStatus = _storeCurrentLocs(opCtx);
if (!storeCurrentLocsStatus.isOK()) {
return storeCurrentLocsStatus;
}
}
// Tell the recipient shard to start cloning
BSONObjBuilder cmdBuilder;
StartChunkCloneRequest::appendAsCommand(&cmdBuilder,
_args.getNss(),
_sessionId,
_donorConnStr,
_args.getFromShardId(),
_args.getToShardId(),
_args.getMinKey(),
_args.getMaxKey(),
_shardKeyPattern.toBSON(),
_args.getSecondaryThrottle());
auto startChunkCloneResponseStatus = _callRecipient(cmdBuilder.obj());
if (!startChunkCloneResponseStatus.isOK()) {
return startChunkCloneResponseStatus.getStatus();
}
// TODO (Kal): Setting the state to kCloning below means that if cancelClone was called we will
// send a cancellation command to the recipient. The reason to limit the cases when we send
// cancellation is for backwards compatibility with 3.2 nodes, which cannot differentiate
// between cancellations for different migration sessions. It is thus possible that a second
// migration from different donor, but the same recipient would certainly abort an already
// running migration.
stdx::lock_guard<Latch> sl(_mutex);
_state = kCloning;
return Status::OK();
}
Status MigrationChunkClonerSourceLegacy::awaitUntilCriticalSectionIsAppropriate(
OperationContext* opCtx, Milliseconds maxTimeToWait) {
invariant(_state == kCloning);
invariant(!opCtx->lockState()->isLocked());
const auto startTime = Date_t::now();
int iteration = 0;
while ((Date_t::now() - startTime) < maxTimeToWait) {
auto responseStatus = _callRecipient(
createRequestWithSessionId(kRecvChunkStatus, _args.getNss(), _sessionId, true));
if (!responseStatus.isOK()) {
return responseStatus.getStatus().withContext(
"Failed to contact recipient shard to monitor data transfer");
}
const BSONObj& res = responseStatus.getValue();
if (!res["waited"].boolean()) {
sleepmillis(1LL << std::min(iteration, 10));
}
iteration++;
stdx::lock_guard<Latch> sl(_mutex);
const std::size_t cloneLocsRemaining = _cloneLocs.size();
log() << "moveChunk data transfer progress: " << redact(res) << " mem used: " << _memoryUsed
<< " documents remaining to clone: " << cloneLocsRemaining;
if (res["state"].String() == "steady") {
if (cloneLocsRemaining != 0) {
return {ErrorCodes::OperationIncomplete,
str::stream() << "Unable to enter critical section because the recipient "
"shard thinks all data is cloned while there are still "
<< cloneLocsRemaining << " documents remaining"};
}
return Status::OK();
}
if (res["state"].String() == "fail") {
return {ErrorCodes::OperationFailed,
str::stream() << "Data transfer error: " << res["errmsg"].str()};
}
auto migrationSessionIdStatus = MigrationSessionId::extractFromBSON(res);
if (!migrationSessionIdStatus.isOK()) {
return {ErrorCodes::OperationIncomplete,
str::stream() << "Unable to retrieve the id of the migration session due to "
<< migrationSessionIdStatus.getStatus().toString()};
}
if (res["ns"].str() != _args.getNss().ns() ||
(res.hasField("fromShardId")
? (res["fromShardId"].str() != _args.getFromShardId().toString())
: (res["from"].str() != _donorConnStr.toString())) ||
!res["min"].isABSONObj() || res["min"].Obj().woCompare(_args.getMinKey()) != 0 ||
!res["max"].isABSONObj() || res["max"].Obj().woCompare(_args.getMaxKey()) != 0 ||
!_sessionId.matches(migrationSessionIdStatus.getValue())) {
// This can happen when the destination aborted the migration and received another
// recvChunk before this thread sees the transition to the abort state. This is
// currently possible only if multiple migrations are happening at once. This is an
// unfortunate consequence of the shards not being able to keep track of multiple
// incoming and outgoing migrations.
return {ErrorCodes::OperationIncomplete,
"Destination shard aborted migration because a new one is running"};
}
if (_memoryUsed > 500 * 1024 * 1024) {
// This is too much memory for us to use so we're going to abort the migration
return {ErrorCodes::ExceededMemoryLimit,
"Aborting migration because of high memory usage"};
}
Status interruptStatus = opCtx->checkForInterruptNoAssert();
if (!interruptStatus.isOK()) {
return interruptStatus;
}
}
return {ErrorCodes::ExceededTimeLimit, "Timed out waiting for the cloner to catch up"};
}
StatusWith<BSONObj> MigrationChunkClonerSourceLegacy::commitClone(OperationContext* opCtx) {
invariant(_state == kCloning);
invariant(!opCtx->lockState()->isLocked());
if (_sessionCatalogSource) {
_sessionCatalogSource->onCommitCloneStarted();
}
auto responseStatus =
_callRecipient(createRequestWithSessionId(kRecvChunkCommit, _args.getNss(), _sessionId));
if (responseStatus.isOK()) {
_cleanup(opCtx);
if (_sessionCatalogSource && _sessionCatalogSource->hasMoreOplog()) {
return {ErrorCodes::SessionTransferIncomplete,
"destination shard finished committing but there are still some session "
"metadata that needs to be transferred"};
}
return responseStatus;
}
cancelClone(opCtx);
return responseStatus.getStatus();
}
void MigrationChunkClonerSourceLegacy::cancelClone(OperationContext* opCtx) {
invariant(!opCtx->lockState()->isLocked());
if (_sessionCatalogSource) {
_sessionCatalogSource->onCloneCleanup();
}
switch (_state) {
case kDone:
break;
case kCloning: {
const auto status = _callRecipient(createRequestWithSessionId(
kRecvChunkAbort, _args.getNss(), _sessionId))
.getStatus();
if (!status.isOK()) {
LOG(0) << "Failed to cancel migration " << causedBy(redact(status));
}
}
// Intentional fall through
case kNew:
_cleanup(opCtx);
break;
default:
MONGO_UNREACHABLE;
}
}
bool MigrationChunkClonerSourceLegacy::isDocumentInMigratingChunk(const BSONObj& doc) {
return isInRange(doc, _args.getMinKey(), _args.getMaxKey(), _shardKeyPattern);
}
void MigrationChunkClonerSourceLegacy::onInsertOp(OperationContext* opCtx,
const BSONObj& insertedDoc,
const repl::OpTime& opTime) {
dassert(opCtx->lockState()->isCollectionLockedForMode(_args.getNss(), MODE_IX));
BSONElement idElement = insertedDoc["_id"];
if (idElement.eoo()) {
warning() << "logInsertOp got a document with no _id field, ignoring inserted document: "
<< redact(insertedDoc);
return;
}
if (!isInRange(insertedDoc, _args.getMinKey(), _args.getMaxKey(), _shardKeyPattern)) {
return;
}
if (!_addedOperationToOutstandingOperationTrackRequests()) {
return;
}
if (opCtx->getTxnNumber()) {
opCtx->recoveryUnit()->registerChange(std::make_unique<LogOpForShardingHandler>(
this, idElement.wrap(), 'i', opTime, repl::OpTime()));
} else {
opCtx->recoveryUnit()->registerChange(std::make_unique<LogOpForShardingHandler>(
this, idElement.wrap(), 'i', repl::OpTime(), repl::OpTime()));
}
}
void MigrationChunkClonerSourceLegacy::onUpdateOp(OperationContext* opCtx,
boost::optional<BSONObj> preImageDoc,
const BSONObj& postImageDoc,
const repl::OpTime& opTime,
const repl::OpTime& prePostImageOpTime) {
dassert(opCtx->lockState()->isCollectionLockedForMode(_args.getNss(), MODE_IX));
BSONElement idElement = postImageDoc["_id"];
if (idElement.eoo()) {
warning() << "logUpdateOp got a document with no _id field, ignoring updatedDoc: "
<< redact(postImageDoc);
return;
}
if (!isInRange(postImageDoc, _args.getMinKey(), _args.getMaxKey(), _shardKeyPattern)) {
// If the preImageDoc is not in range but the postImageDoc was, we know that the document
// has changed shard keys and no longer belongs in the chunk being cloned. We will model
// the deletion of the preImage document so that the destination chunk does not receive an
// outdated version of this document.
if (preImageDoc &&
isInRange(*preImageDoc, _args.getMinKey(), _args.getMaxKey(), _shardKeyPattern)) {
onDeleteOp(opCtx, *preImageDoc, opTime, prePostImageOpTime);
}
return;
}
if (!_addedOperationToOutstandingOperationTrackRequests()) {
return;
}
if (opCtx->getTxnNumber()) {
opCtx->recoveryUnit()->registerChange(std::make_unique<LogOpForShardingHandler>(
this, idElement.wrap(), 'u', opTime, prePostImageOpTime));
} else {
opCtx->recoveryUnit()->registerChange(std::make_unique<LogOpForShardingHandler>(
this, idElement.wrap(), 'u', repl::OpTime(), repl::OpTime()));
}
}
void MigrationChunkClonerSourceLegacy::onDeleteOp(OperationContext* opCtx,
const BSONObj& deletedDocId,
const repl::OpTime& opTime,
const repl::OpTime& preImageOpTime) {
dassert(opCtx->lockState()->isCollectionLockedForMode(_args.getNss(), MODE_IX));
BSONElement idElement = deletedDocId["_id"];
if (idElement.eoo()) {
warning() << "logDeleteOp got a document with no _id field, ignoring deleted doc: "
<< redact(deletedDocId);
return;
}
if (!_addedOperationToOutstandingOperationTrackRequests()) {
return;
}
if (opCtx->getTxnNumber()) {
opCtx->recoveryUnit()->registerChange(std::make_unique<LogOpForShardingHandler>(
this, idElement.wrap(), 'd', opTime, preImageOpTime));
} else {
opCtx->recoveryUnit()->registerChange(std::make_unique<LogOpForShardingHandler>(
this, idElement.wrap(), 'd', repl::OpTime(), repl::OpTime()));
}
}
void MigrationChunkClonerSourceLegacy::_addToSessionMigrationOptimeQueue(
const repl::OpTime& opTime,
SessionCatalogMigrationSource::EntryAtOpTimeType entryAtOpTimeType) {
if (auto sessionSource = _sessionCatalogSource.get()) {
if (!opTime.isNull()) {
sessionSource->notifyNewWriteOpTime(opTime, entryAtOpTimeType);
}
}
}
void MigrationChunkClonerSourceLegacy::_addToTransferModsQueue(
const BSONObj& idObj,
const char op,
const repl::OpTime& opTime,
const repl::OpTime& prePostImageOpTime) {
switch (op) {
case 'd': {
stdx::lock_guard<Latch> sl(_mutex);
_deleted.push_back(idObj);
_memoryUsed += idObj.firstElement().size() + 5;
} break;
case 'i':
case 'u': {
stdx::lock_guard<Latch> sl(_mutex);
_reload.push_back(idObj);
_memoryUsed += idObj.firstElement().size() + 5;
} break;
default:
MONGO_UNREACHABLE;
}
_addToSessionMigrationOptimeQueue(
prePostImageOpTime, SessionCatalogMigrationSource::EntryAtOpTimeType::kRetryableWrite);
_addToSessionMigrationOptimeQueue(
opTime, SessionCatalogMigrationSource::EntryAtOpTimeType::kRetryableWrite);
}
bool MigrationChunkClonerSourceLegacy::_addedOperationToOutstandingOperationTrackRequests() {
stdx::unique_lock<Latch> lk(_mutex);
if (!_acceptingNewOperationTrackRequests) {
return false;
}
_incrementOutstandingOperationTrackRequests(lk);
return true;
}
void MigrationChunkClonerSourceLegacy::_drainAllOutstandingOperationTrackRequests(
stdx::unique_lock<Latch>& lk) {
invariant(_state == kDone);
_acceptingNewOperationTrackRequests = false;
_allOutstandingOperationTrackRequestsDrained.wait(
lk, [&] { return _outstandingOperationTrackRequests == 0; });
}
void MigrationChunkClonerSourceLegacy::_incrementOutstandingOperationTrackRequests(WithLock) {
invariant(_acceptingNewOperationTrackRequests);
++_outstandingOperationTrackRequests;
}
void MigrationChunkClonerSourceLegacy::_decrementOutstandingOperationTrackRequests() {
stdx::lock_guard<Latch> sl(_mutex);
--_outstandingOperationTrackRequests;
if (_outstandingOperationTrackRequests == 0) {
_allOutstandingOperationTrackRequestsDrained.notify_all();
}
}
uint64_t MigrationChunkClonerSourceLegacy::getCloneBatchBufferAllocationSize() {
stdx::lock_guard<Latch> sl(_mutex);
return std::min(static_cast<uint64_t>(BSONObjMaxUserSize),
_averageObjectSizeForCloneLocs * _cloneLocs.size());
}
Status MigrationChunkClonerSourceLegacy::nextCloneBatch(OperationContext* opCtx,
Collection* collection,
BSONArrayBuilder* arrBuilder) {
dassert(opCtx->lockState()->isCollectionLockedForMode(_args.getNss(), MODE_IS));
ElapsedTracker tracker(opCtx->getServiceContext()->getFastClockSource(),
internalQueryExecYieldIterations.load(),
Milliseconds(internalQueryExecYieldPeriodMS.load()));
stdx::unique_lock<Latch> lk(_mutex);
auto iter = _cloneLocs.begin();
for (; iter != _cloneLocs.end(); ++iter) {
// We must always make progress in this method by at least one document because empty return
// indicates there is no more initial clone data.
if (arrBuilder->arrSize() && tracker.intervalHasElapsed()) {
break;
}
auto nextRecordId = *iter;
lk.unlock();
Snapshotted<BSONObj> doc;
if (collection->findDoc(opCtx, nextRecordId, &doc)) {
// Use the builder size instead of accumulating the document sizes directly so
// that we take into consideration the overhead of BSONArray indices.
if (arrBuilder->arrSize() &&
(arrBuilder->len() + doc.value().objsize() + 1024) > BSONObjMaxUserSize) {
break;
}
arrBuilder->append(doc.value());
ShardingStatistics::get(opCtx).countDocsClonedOnDonor.addAndFetch(1);
}
lk.lock();
}
_cloneLocs.erase(_cloneLocs.begin(), iter);
return Status::OK();
}
Status MigrationChunkClonerSourceLegacy::nextModsBatch(OperationContext* opCtx,
Database* db,
BSONObjBuilder* builder) {
dassert(opCtx->lockState()->isCollectionLockedForMode(_args.getNss(), MODE_IS));
std::list<BSONObj> deleteList;
std::list<BSONObj> updateList;
{
// All clone data must have been drained before starting to fetch the incremental changes.
stdx::unique_lock<Latch> lk(_mutex);
invariant(_cloneLocs.empty());
// The "snapshot" for delete and update list must be taken under a single lock. This is to
// ensure that we will preserve the causal order of writes. Always consume the delete
// buffer first, before the update buffer. If the delete is causally before the update to
// the same doc, then there's no problem since we consume the delete buffer first. If the
// delete is causally after, we will not be able to see the document when we attempt to
// fetch it, so it's also ok.
deleteList.splice(deleteList.cbegin(), _deleted);
updateList.splice(updateList.cbegin(), _reload);
}
auto totalDocSize = _xferDeletes(builder, &deleteList, 0);
totalDocSize = _xferUpdates(opCtx, db, builder, &updateList, totalDocSize);
builder->append("size", totalDocSize);
// Put back remaining ids we didn't consume
stdx::unique_lock<Latch> lk(_mutex);
_deleted.splice(_deleted.cbegin(), deleteList);
_reload.splice(_reload.cbegin(), updateList);
return Status::OK();
}
void MigrationChunkClonerSourceLegacy::_cleanup(OperationContext* opCtx) {
stdx::unique_lock<Latch> lk(_mutex);
_state = kDone;
_drainAllOutstandingOperationTrackRequests(lk);
_reload.clear();
_deleted.clear();
}
StatusWith<BSONObj> MigrationChunkClonerSourceLegacy::_callRecipient(const BSONObj& cmdObj) {
executor::RemoteCommandResponse responseStatus(
Status{ErrorCodes::InternalError, "Uninitialized value"});
auto executor = Grid::get(getGlobalServiceContext())->getExecutorPool()->getFixedExecutor();
auto scheduleStatus = executor->scheduleRemoteCommand(
executor::RemoteCommandRequest(_recipientHost, "admin", cmdObj, nullptr),
[&responseStatus](const executor::TaskExecutor::RemoteCommandCallbackArgs& args) {
responseStatus = args.response;
});
// TODO: Update RemoteCommandTargeter on NotMaster errors.
if (!scheduleStatus.isOK()) {
return scheduleStatus.getStatus();
}
executor->wait(scheduleStatus.getValue());
if (!responseStatus.isOK()) {
return responseStatus.status;
}
Status commandStatus = getStatusFromCommandResult(responseStatus.data);
if (!commandStatus.isOK()) {
return commandStatus;
}
return responseStatus.data.getOwned();
}
Status MigrationChunkClonerSourceLegacy::_storeCurrentLocs(OperationContext* opCtx) {
AutoGetCollection autoColl(opCtx, _args.getNss(), MODE_IS);
Collection* const collection = autoColl.getCollection();
if (!collection) {
return {ErrorCodes::NamespaceNotFound,
str::stream() << "Collection " << _args.getNss().ns() << " does not exist."};
}
// Allow multiKey based on the invariant that shard keys must be single-valued. Therefore, any
// multi-key index prefixed by shard key cannot be multikey over the shard key fields.
const IndexDescriptor* idx =
collection->getIndexCatalog()->findShardKeyPrefixedIndex(opCtx,
_shardKeyPattern.toBSON(),
false); // requireSingleKey
if (!idx) {
return {ErrorCodes::IndexNotFound,
str::stream() << "can't find index with prefix " << _shardKeyPattern.toBSON()
<< " in storeCurrentLocs for " << _args.getNss().ns()};
}
// Assume both min and max non-empty, append MinKey's to make them fit chosen index
const KeyPattern kp(idx->keyPattern());
BSONObj min = Helpers::toKeyFormat(kp.extendRangeBound(_args.getMinKey(), false));
BSONObj max = Helpers::toKeyFormat(kp.extendRangeBound(_args.getMaxKey(), false));
// We can afford to yield here because any change to the base data that we might miss is already
// being queued and will migrate in the 'transferMods' stage.
auto exec = InternalPlanner::indexScan(opCtx,
collection,
idx,
min,
max,
BoundInclusion::kIncludeStartKeyOnly,
PlanExecutor::YIELD_AUTO);
// Use the average object size to estimate how many objects a full chunk would carry do that
// while traversing the chunk's range using the sharding index, below there's a fair amount of
// slack before we determine a chunk is too large because object sizes will vary.
unsigned long long maxRecsWhenFull;
long long avgRecSize;
const long long totalRecs = collection->numRecords(opCtx);
if (totalRecs > 0) {
avgRecSize = collection->dataSize(opCtx) / totalRecs;
maxRecsWhenFull = _args.getMaxChunkSizeBytes() / avgRecSize;
maxRecsWhenFull = 130 * maxRecsWhenFull / 100; // pad some slack
} else {
avgRecSize = 0;
maxRecsWhenFull = kMaxObjectPerChunk + 1;
}
// Do a full traversal of the chunk and don't stop even if we think it is a large chunk we want
// the number of records to better report, in that case.
bool isLargeChunk = false;
unsigned long long recCount = 0;
BSONObj obj;
RecordId recordId;
PlanExecutor::ExecState state;
while (PlanExecutor::ADVANCED == (state = exec->getNext(&obj, &recordId))) {
Status interruptStatus = opCtx->checkForInterruptNoAssert();
if (!interruptStatus.isOK()) {
return interruptStatus;
}
if (!isLargeChunk) {
stdx::lock_guard<Latch> lk(_mutex);
_cloneLocs.insert(recordId);
}
if (++recCount > maxRecsWhenFull) {
isLargeChunk = true;
// Continue on despite knowing that it will fail, just to get the correct value for
// recCount
}
}
if (PlanExecutor::FAILURE == state) {
return WorkingSetCommon::getMemberObjectStatus(obj).withContext(
"Executor error while scanning for documents belonging to chunk");
}
const uint64_t collectionAverageObjectSize = collection->averageObjectSize(opCtx);
if (isLargeChunk) {
return {
ErrorCodes::ChunkTooBig,
str::stream() << "Cannot move chunk: the maximum number of documents for a chunk is "
<< maxRecsWhenFull << ", the maximum chunk size is "
<< _args.getMaxChunkSizeBytes() << ", average document size is "
<< avgRecSize << ". Found " << recCount << " documents in chunk "
<< " ns: " << _args.getNss().ns() << " " << _args.getMinKey() << " -> "
<< _args.getMaxKey()};
}
stdx::lock_guard<Latch> lk(_mutex);
_averageObjectSizeForCloneLocs = collectionAverageObjectSize + 12;
return Status::OK();
}
long long MigrationChunkClonerSourceLegacy::_xferDeletes(BSONObjBuilder* builder,
std::list<BSONObj>* removeList,
long long initialSize) {
const long long maxSize = 1024 * 1024;
if (removeList->empty() || initialSize > maxSize) {
return initialSize;
}
long long totalSize = initialSize;
BSONArrayBuilder arr(builder->subarrayStart("deleted"));
auto docIdIter = removeList->begin();
for (; docIdIter != removeList->end() && totalSize < maxSize; ++docIdIter) {
BSONObj idDoc = *docIdIter;
arr.append(idDoc);
totalSize += idDoc.objsize();
}
removeList->erase(removeList->begin(), docIdIter);
arr.done();
return totalSize;
}
long long MigrationChunkClonerSourceLegacy::_xferUpdates(OperationContext* opCtx,
Database* db,
BSONObjBuilder* builder,
std::list<BSONObj>* updateList,
long long initialSize) {
const long long maxSize = 1024 * 1024;
if (updateList->empty() || initialSize > maxSize) {
return initialSize;
}
const auto& nss = _args.getNss();
BSONArrayBuilder arr(builder->subarrayStart("reload"));
long long totalSize = initialSize;
auto iter = updateList->begin();
for (; iter != updateList->end() && totalSize < maxSize; ++iter) {
auto idDoc = *iter;
BSONObj fullDoc;
if (Helpers::findById(opCtx, db, nss.ns().c_str(), idDoc, fullDoc)) {
arr.append(fullDoc);
totalSize += fullDoc.objsize();
}
}
updateList->erase(updateList->begin(), iter);
arr.done();
return totalSize;
}
boost::optional<repl::OpTime> MigrationChunkClonerSourceLegacy::nextSessionMigrationBatch(
OperationContext* opCtx, BSONArrayBuilder* arrBuilder) {
if (!_sessionCatalogSource) {
return boost::none;
}
repl::OpTime opTimeToWaitIfWaitingForMajority;
const ChunkRange range(_args.getMinKey(), _args.getMaxKey());
while (_sessionCatalogSource->hasMoreOplog()) {
auto result = _sessionCatalogSource->getLastFetchedOplog();
if (!result.oplog) {
_sessionCatalogSource->fetchNextOplog(opCtx);
continue;
}
auto newOpTime = result.oplog->getOpTime();
auto oplogDoc = result.oplog->toBSON();
// Use the builder size instead of accumulating the document sizes directly so that we
// take into consideration the overhead of BSONArray indices.
if (arrBuilder->arrSize() &&
(arrBuilder->len() + oplogDoc.objsize() + 1024) > BSONObjMaxUserSize) {
break;
}
arrBuilder->append(oplogDoc);
_sessionCatalogSource->fetchNextOplog(opCtx);
if (result.shouldWaitForMajority) {
if (opTimeToWaitIfWaitingForMajority < newOpTime) {
opTimeToWaitIfWaitingForMajority = newOpTime;
}
}
}
return boost::make_optional(opTimeToWaitIfWaitingForMajority);
}
std::shared_ptr<Notification<bool>>
MigrationChunkClonerSourceLegacy::getNotificationForNextSessionMigrationBatch() {
if (!_sessionCatalogSource) {
return nullptr;
}
return _sessionCatalogSource->getNotificationForNewOplog();
}
} // namespace mongo
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