boost::optional<ScopedCollectionMetadata> MetadataManager::getActiveMetadata(
std::shared_ptr<MetadataManager> self, const boost::optional<LogicalTime>& atClusterTime) {
stdx::lock_guard<stdx::mutex> lg(_managerLock);
if (_metadata.empty()) {
return boost::none;
}
auto activeMetadataTracker = _metadata.back();
const auto& activeMetadata = activeMetadataTracker->metadata;
// We don't keep routing history for unsharded collections, so if the collection is unsharded
// just return the active metadata
if (!atClusterTime || !activeMetadata.isSharded()) {
return ScopedCollectionMetadata(std::make_shared<RangePreserver>(
lg, std::move(self), std::move(activeMetadataTracker)));
}
auto chunkManager = activeMetadata.getChunkManager();
auto chunkManagerAtClusterTime = std::make_shared<ChunkManager>(
chunkManager->getRoutingHistory(), atClusterTime->asTimestamp());
class MetadataAtTimestamp : public ScopedCollectionMetadata::Impl {
public:
MetadataAtTimestamp(CollectionMetadata metadata) : _metadata(std::move(metadata)) {}
const CollectionMetadata& get() override {
return _metadata;
}
private:
CollectionMetadata _metadata;
};
return ScopedCollectionMetadata(std::make_shared<MetadataAtTimestamp>(
CollectionMetadata(chunkManagerAtClusterTime, activeMetadata.shardId())));
}
ChunkVersion forceShardFilteringMetadataRefresh(OperationContext* opCtx,
const NamespaceString& nss,
bool forceRefreshFromThisThread) {
invariant(!opCtx->lockState()->isLocked());
invariant(!opCtx->getClient()->isInDirectClient());
auto* const shardingState = ShardingState::get(opCtx);
invariant(shardingState->canAcceptShardedCommands());
auto routingInfo =
uassertStatusOK(Grid::get(opCtx)->catalogCache()->getCollectionRoutingInfoWithRefresh(
opCtx, nss, forceRefreshFromThisThread));
auto cm = routingInfo.cm();
if (!cm) {
// No chunk manager, so unsharded.
// Exclusive collection lock needed since we're now changing the metadata
AutoGetCollection autoColl(opCtx, nss, MODE_IX, MODE_X);
CollectionShardingRuntime::get(opCtx, nss)
->setFilteringMetadata(opCtx, CollectionMetadata());
return ChunkVersion::UNSHARDED();
}
// Optimistic check with only IS lock in order to avoid threads piling up on the collection X
// lock below
{
AutoGetCollection autoColl(opCtx, nss, MODE_IS);
auto optMetadata = CollectionShardingState::get(opCtx, nss)->getCurrentMetadataIfKnown();
// We already have newer version
if (optMetadata) {
const auto& metadata = *optMetadata;
if (metadata->isSharded() &&
metadata->getCollVersion().epoch() == cm->getVersion().epoch() &&
metadata->getCollVersion() >= cm->getVersion()) {
LOG(1) << "Skipping refresh of metadata for " << nss << " "
<< metadata->getCollVersion() << " with an older " << cm->getVersion();
return metadata->getShardVersion();
}
}
}
// Exclusive collection lock needed since we're now changing the metadata
AutoGetCollection autoColl(opCtx, nss, MODE_IX, MODE_X);
auto* const css = CollectionShardingRuntime::get(opCtx, nss);
{
auto optMetadata = CollectionShardingState::get(opCtx, nss)->getCurrentMetadataIfKnown();
// We already have newer version
if (optMetadata) {
const auto& metadata = *optMetadata;
if (metadata->isSharded() &&
metadata->getCollVersion().epoch() == cm->getVersion().epoch() &&
metadata->getCollVersion() >= cm->getVersion()) {
LOG(1) << "Skipping refresh of metadata for " << nss << " "
<< metadata->getCollVersion() << " with an older " << cm->getVersion();
return metadata->getShardVersion();
}
}
}
CollectionMetadata metadata(std::move(cm), shardingState->shardId());
const auto newShardVersion = metadata.getShardVersion();
css->setFilteringMetadata(opCtx, std::move(metadata));
return newShardVersion;
}