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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/bson/simple_bsonelement_comparator.h"
#include "mongo/bson/util/bson_extract.h"
#include "mongo/db/audit.h"
#include "mongo/db/auth/action_type.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/catalog_raii.h"
#include "mongo/db/commands.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/hasher.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/logical_clock.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/query/collation/collator_factory_interface.h"
#include "mongo/db/s/active_shard_collection_registry.h"
#include "mongo/db/s/collection_sharding_runtime.h"
#include "mongo/db/s/config/initial_split_policy.h"
#include "mongo/db/s/config/sharding_catalog_manager.h"
#include "mongo/db/s/shard_filtering_metadata_refresh.h"
#include "mongo/db/s/sharding_logging.h"
#include "mongo/db/s/sharding_state.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/s/balancer_configuration.h"
#include "mongo/s/catalog/sharding_catalog_client_impl.h"
#include "mongo/s/catalog/type_database.h"
#include "mongo/s/catalog/type_shard.h"
#include "mongo/s/catalog/type_tags.h"
#include "mongo/s/cluster_commands_helpers.h"
#include "mongo/s/grid.h"
#include "mongo/s/request_types/clone_collection_options_from_primary_shard_gen.h"
#include "mongo/s/request_types/shard_collection_gen.h"
#include "mongo/s/shard_util.h"
#include "mongo/util/log.h"
#include "mongo/util/scopeguard.h"
#include "mongo/util/str.h"
namespace mongo {
namespace {
struct ShardCollectionTargetState {
UUID uuid;
ShardKeyPattern shardKeyPattern;
std::vector<TagsType> tags;
bool collectionIsEmpty;
std::vector<BSONObj> splitPoints;
int numContiguousChunksPerShard;
bool fromMapReduce;
};
const ReadPreferenceSetting kConfigReadSelector(ReadPreference::Nearest, TagSet{});
/**
* If the specified status is not OK logs a warning and throws a DBException corresponding to the
* specified status.
*/
void uassertStatusOKWithWarning(const Status& status) {
if (!status.isOK()) {
warning() << "shardsvrShardCollection failed" << causedBy(redact(status));
uassertStatusOK(status);
}
}
void checkForExistingChunks(OperationContext* opCtx, const NamespaceString& nss) {
BSONObjBuilder countBuilder;
countBuilder.append("count", ChunkType::ConfigNS.coll());
countBuilder.append("query", BSON(ChunkType::ns(nss.ns())));
// OK to use limit=1, since if any chunks exist, we will fail.
countBuilder.append("limit", 1);
// Use readConcern local to guarantee we see any chunks that have been written and may
// become committed; readConcern majority will not see the chunks if they have not made it
// to the majority snapshot.
repl::ReadConcernArgs readConcern(Grid::get(opCtx)->configOpTime(),
repl::ReadConcernLevel::kMajorityReadConcern);
readConcern.appendInfo(&countBuilder);
auto cmdResponse = uassertStatusOK(
Grid::get(opCtx)->shardRegistry()->getConfigShard()->runCommandWithFixedRetryAttempts(
opCtx,
kConfigReadSelector,
ChunkType::ConfigNS.db().toString(),
countBuilder.done(),
Shard::kDefaultConfigCommandTimeout,
Shard::RetryPolicy::kIdempotent));
uassertStatusOK(cmdResponse.commandStatus);
long long numChunks;
uassertStatusOK(bsonExtractIntegerField(cmdResponse.response, "n", &numChunks));
uassert(ErrorCodes::ManualInterventionRequired,
str::stream() << "A previous attempt to shard collection " << nss.ns()
<< " failed after writing some initial chunks to config.chunks. Please "
"manually delete the partially written chunks for collection "
<< nss.ns() << " from config.chunks",
numChunks == 0);
}
/**
* Constructs the BSON specification document for the given namespace, index key and options.
*/
BSONObj makeCreateIndexesCmd(const NamespaceString& nss,
const BSONObj& keys,
const BSONObj& collation,
bool unique) {
BSONObjBuilder index;
// Required fields for an index.
index.append("key", keys);
StringBuilder indexName;
bool isFirstKey = true;
for (BSONObjIterator keyIter(keys); keyIter.more();) {
BSONElement currentKey = keyIter.next();
if (isFirstKey) {
isFirstKey = false;
} else {
indexName << "_";
}
indexName << currentKey.fieldName() << "_";
if (currentKey.isNumber()) {
indexName << currentKey.numberInt();
} else {
indexName << currentKey.str(); // this should match up with shell command
}
}
index.append("name", indexName.str());
// Index options.
if (!collation.isEmpty()) {
// Creating an index with the "collation" option requires a v=2 index.
index.append("v", static_cast<int>(IndexDescriptor::IndexVersion::kV2));
index.append("collation", collation);
}
if (unique && !IndexDescriptor::isIdIndexPattern(keys)) {
index.appendBool("unique", unique);
}
// The outer createIndexes command.
BSONObjBuilder createIndexes;
createIndexes.append("createIndexes", nss.coll());
createIndexes.append("indexes", BSON_ARRAY(index.obj()));
createIndexes.append("writeConcern", WriteConcernOptions::Majority);
return appendAllowImplicitCreate(createIndexes.obj(), true);
}
/**
* Compares the proposed shard key with the collection's existing indexes on the primary shard to
* ensure they are a legal combination.
*
* If the collection is empty and no index on the shard key exists, creates the required index.
*/
void createCollectionOrValidateExisting(OperationContext* opCtx,
const NamespaceString& nss,
const BSONObj& proposedKey,
const ShardKeyPattern& shardKeyPattern,
const ShardsvrShardCollection& request) {
// The proposed shard key must be validated against the set of existing indexes.
// In particular, we must ensure the following constraints
//
// 1. All existing unique indexes, except those which start with the _id index,
// must contain the proposed key as a prefix (uniqueness of the _id index is
// ensured by the _id generation process or guaranteed by the user).
//
// 2. If the collection is not empty, there must exist at least one index that
// is "useful" for the proposed key. A "useful" index is defined as follows
// Useful Index:
// i. contains proposedKey as a prefix
// ii. is not a sparse index, partial index, or index with a non-simple collation
// iii. contains no null values
// iv. is not multikey (maybe lift this restriction later)
// v. if a hashed index, has default seed (lift this restriction later)
//
// 3. If the proposed shard key is specified as unique, there must exist a useful,
// unique index exactly equal to the proposedKey (not just a prefix).
//
// After validating these constraint:
//
// 4. If there is no useful index, and the collection is non-empty, we
// must fail.
//
// 5. If the collection is empty, and it's still possible to create an index
// on the proposed key, we go ahead and do so.
DBDirectClient localClient(opCtx);
std::list<BSONObj> indexes = localClient.getIndexSpecs(nss.ns());
// 1. Verify consistency with existing unique indexes
for (const auto& idx : indexes) {
BSONObj currentKey = idx["key"].embeddedObject();
bool isUnique = idx["unique"].trueValue();
uassert(ErrorCodes::InvalidOptions,
str::stream() << "can't shard collection '" << nss.ns() << "' with unique index on "
<< currentKey << " and proposed shard key " << proposedKey
<< ". Uniqueness can't be maintained unless shard key is a prefix",
!isUnique || shardKeyPattern.isUniqueIndexCompatible(currentKey));
}
// 2. Check for a useful index
bool hasUsefulIndexForKey = false;
for (const auto& idx : indexes) {
BSONObj currentKey = idx["key"].embeddedObject();
// Check 2.i. and 2.ii.
if (!idx["sparse"].trueValue() && idx["filter"].eoo() && idx["collation"].eoo() &&
proposedKey.isPrefixOf(currentKey, SimpleBSONElementComparator::kInstance)) {
// We can't currently use hashed indexes with a non-default hash seed
// Check v.
// Note that this means that, for sharding, we only support one hashed index
// per field per collection.
uassert(ErrorCodes::InvalidOptions,
str::stream() << "can't shard collection " << nss.ns()
<< " with hashed shard key " << proposedKey
<< " because the hashed index uses a non-default seed of "
<< idx["seed"].numberInt(),
!shardKeyPattern.isHashedPattern() || idx["seed"].eoo() ||
idx["seed"].numberInt() == BSONElementHasher::DEFAULT_HASH_SEED);
hasUsefulIndexForKey = true;
}
}
// 3. If proposed key is required to be unique, additionally check for exact match.
if (hasUsefulIndexForKey && request.getUnique()) {
BSONObj eqQuery = BSON("key" << proposedKey);
BSONObj eqQueryResult;
for (const auto& idx : indexes) {
if (SimpleBSONObjComparator::kInstance.evaluate(idx["key"].embeddedObject() ==
proposedKey)) {
eqQueryResult = idx;
break;
}
}
if (eqQueryResult.isEmpty()) {
// If no exact match, index not useful, but still possible to create one later
hasUsefulIndexForKey = false;
} else {
bool isExplicitlyUnique = eqQueryResult["unique"].trueValue();
BSONObj currKey = eqQueryResult["key"].embeddedObject();
bool isCurrentID = (currKey.firstElementFieldNameStringData() == "_id");
uassert(ErrorCodes::InvalidOptions,
str::stream() << "can't shard collection " << nss.ns() << ", " << proposedKey
<< " index not unique, and unique index explicitly specified",
isExplicitlyUnique || isCurrentID);
}
}
if (hasUsefulIndexForKey) {
// Check 2.iii and 2.iv. Make sure no null entries in the sharding index
// and that there is a useful, non-multikey index available
BSONObjBuilder checkShardingIndexCmd;
checkShardingIndexCmd.append("checkShardingIndex", nss.ns());
checkShardingIndexCmd.append("keyPattern", proposedKey);
BSONObj res;
auto success = localClient.runCommand("admin", checkShardingIndexCmd.obj(), res);
uassert(ErrorCodes::OperationFailed, res["errmsg"].str(), success);
} else if (!localClient.findOne(nss.ns(), Query()).isEmpty()) {
// 4. if no useful index, and collection is non-empty, fail
uasserted(ErrorCodes::InvalidOptions,
"Please create an index that starts with the proposed shard key before "
"sharding the collection");
} else {
// 5. If no useful index exists, and collection empty, create one on proposedKey.
// Only need to call ensureIndex on primary shard, since indexes get copied to
// receiving shard whenever a migrate occurs.
// If the collection has a default collation, explicitly send the simple
// collation as part of the createIndex request.
BSONObj collation =
!request.getCollation()->isEmpty() ? CollationSpec::kSimpleSpec : BSONObj();
auto createIndexesCmd =
makeCreateIndexesCmd(nss, proposedKey, collation, request.getUnique());
BSONObj res;
localClient.runCommand(nss.db().toString(), createIndexesCmd, res);
uassertStatusOK(getStatusFromCommandResult(res));
}
}
/**
* Compares the proposed shard key with the shard key of the collection's existing zones
* to ensure they are a legal combination.
*/
void validateShardKeyAgainstExistingZones(OperationContext* opCtx,
const BSONObj& proposedKey,
const ShardKeyPattern& shardKeyPattern,
const std::vector<TagsType>& tags) {
for (const auto& tag : tags) {
BSONObjIterator tagMinFields(tag.getMinKey());
BSONObjIterator tagMaxFields(tag.getMaxKey());
BSONObjIterator proposedFields(proposedKey);
while (tagMinFields.more() && proposedFields.more()) {
BSONElement tagMinKeyElement = tagMinFields.next();
BSONElement tagMaxKeyElement = tagMaxFields.next();
uassert(ErrorCodes::InvalidOptions,
str::stream() << "the min and max of the existing zone " << tag.getMinKey()
<< " -->> " << tag.getMaxKey() << " have non-matching keys",
tagMinKeyElement.fieldNameStringData() ==
tagMaxKeyElement.fieldNameStringData());
BSONElement proposedKeyElement = proposedFields.next();
bool match = ((tagMinKeyElement.fieldNameStringData() ==
proposedKeyElement.fieldNameStringData()) &&
((tagMinFields.more() && proposedFields.more()) ||
(!tagMinFields.more() && !proposedFields.more())));
uassert(ErrorCodes::InvalidOptions,
str::stream() << "the proposed shard key " << proposedKey.toString()
<< " does not match with the shard key of the existing zone "
<< tag.getMinKey() << " -->> " << tag.getMaxKey(),
match);
if (ShardKeyPattern::isHashedPatternEl(proposedKeyElement) &&
(tagMinKeyElement.type() != NumberLong || tagMaxKeyElement.type() != NumberLong)) {
uasserted(ErrorCodes::InvalidOptions,
str::stream() << "cannot do hash sharding with the proposed key "
<< proposedKey.toString() << " because there exists a zone "
<< tag.getMinKey() << " -->> " << tag.getMaxKey()
<< " whose boundaries are not "
"of type NumberLong");
}
}
}
}
std::vector<TagsType> getTagsAndValidate(OperationContext* opCtx,
const NamespaceString& nss,
const BSONObj& proposedKey,
const ShardKeyPattern& shardKeyPattern) {
// Read zone info
const auto catalogClient = Grid::get(opCtx)->catalogClient();
auto tags = uassertStatusOK(catalogClient->getTagsForCollection(opCtx, nss));
if (!tags.empty()) {
validateShardKeyAgainstExistingZones(opCtx, proposedKey, shardKeyPattern, tags);
}
return tags;
}
boost::optional<UUID> getUUIDFromPrimaryShard(OperationContext* opCtx, const NamespaceString& nss) {
// Obtain the collection's UUID from the primary shard's listCollections response.
DBDirectClient localClient(opCtx);
BSONObj res;
{
std::list<BSONObj> all =
localClient.getCollectionInfos(nss.db().toString(), BSON("name" << nss.coll()));
if (!all.empty()) {
res = all.front().getOwned();
}
}
uassert(ErrorCodes::InternalError,
str::stream() << "expected to have an entry for " << nss.toString()
<< " in listCollections response, but did not",
!res.isEmpty());
BSONObj collectionInfo;
if (res["info"].type() == BSONType::Object) {
collectionInfo = res["info"].Obj();
}
uassert(ErrorCodes::InternalError,
str::stream() << "expected to return 'info' field as part of "
"listCollections for "
<< nss.ns()
<< " because the cluster is in featureCompatibilityVersion=3.6, but got "
<< res,
!collectionInfo.isEmpty());
uassert(ErrorCodes::InternalError,
str::stream() << "expected to return a UUID for collection " << nss.ns()
<< " as part of 'info' field but got " << res,
collectionInfo.hasField("uuid"));
return uassertStatusOK(UUID::parse(collectionInfo["uuid"]));
}
UUID getOrGenerateUUID(OperationContext* opCtx,
const NamespaceString& nss,
const ShardsvrShardCollection& request) {
if (request.getGetUUIDfromPrimaryShard()) {
return *getUUIDFromPrimaryShard(opCtx, nss);
}
return UUID::gen();
}
bool checkIfCollectionIsEmpty(OperationContext* opCtx, const NamespaceString& nss) {
// Use find with predicate instead of count in order to ensure that the count
// command doesn't just consult the cached metadata, which may not always be
// correct
DBDirectClient localClient(opCtx);
return localClient.findOne(nss.ns(), Query()).isEmpty();
}
int getNumShards(OperationContext* opCtx) {
const auto shardRegistry = Grid::get(opCtx)->shardRegistry();
shardRegistry->reload(opCtx);
std::vector<ShardId> shardIds;
shardRegistry->getAllShardIds(opCtx, &shardIds);
return shardIds.size();
}
struct SplitPoints {
std::vector<BSONObj> initialPoints;
std::vector<BSONObj> finalPoints;
};
SplitPoints calculateInitialAndFinalSplitPoints(const ShardsvrShardCollection& request,
const ShardKeyPattern& shardKeyPattern,
std::vector<TagsType>& tags,
int numShards,
bool collectionIsEmpty) {
std::vector<BSONObj> initialSplitPoints;
std::vector<BSONObj> finalSplitPoints;
if (request.getInitialSplitPoints()) {
finalSplitPoints = *request.getInitialSplitPoints();
} else if (tags.empty()) {
InitialSplitPolicy::calculateHashedSplitPointsForEmptyCollection(
shardKeyPattern,
collectionIsEmpty,
numShards,
request.getNumInitialChunks(),
&initialSplitPoints,
&finalSplitPoints);
}
return {std::move(initialSplitPoints), std::move(finalSplitPoints)};
}
ShardCollectionTargetState calculateTargetState(OperationContext* opCtx,
const NamespaceString& nss,
const ShardsvrShardCollection& request) {
// Fail if there are partially written chunks from a previous failed shardCollection.
checkForExistingChunks(opCtx, nss);
auto proposedKey(request.getKey().getOwned());
ShardKeyPattern shardKeyPattern(proposedKey);
createCollectionOrValidateExisting(opCtx, nss, proposedKey, shardKeyPattern, request);
auto tags = getTagsAndValidate(opCtx, nss, proposedKey, shardKeyPattern);
auto uuid = getOrGenerateUUID(opCtx, nss, request);
const bool isEmpty = checkIfCollectionIsEmpty(opCtx, nss);
const bool fromMapReduce = bool(request.getInitialSplitPoints());
// Map/reduce with output to an empty collection assumes it has full control of the
// output collection and it would be an unsupported operation if the collection is
// being concurrently written
if (fromMapReduce) {
uassert(ErrorCodes::ConflictingOperationInProgress,
str::stream() << "Map reduce with sharded output to a new collection found "
<< nss.ns() << " to be non-empty which is not supported.",
isEmpty);
}
int numShards = getNumShards(opCtx);
auto splitPoints =
calculateInitialAndFinalSplitPoints(request, shardKeyPattern, tags, numShards, isEmpty);
auto initialSplitPoints = splitPoints.initialPoints;
auto finalSplitPoints = splitPoints.finalPoints;
const int numContiguousChunksPerShard = initialSplitPoints.empty()
? 1
: (finalSplitPoints.size() + 1) / (initialSplitPoints.size() + 1);
return {uuid,
std::move(shardKeyPattern),
tags,
isEmpty,
finalSplitPoints,
numContiguousChunksPerShard};
}
void logStartShardCollection(OperationContext* opCtx,
const BSONObj& cmdObj,
const NamespaceString& nss,
const ShardsvrShardCollection& request,
const ShardCollectionTargetState& prerequisites,
const ShardId& dbPrimaryShardId) {
LOG(0) << "CMD: shardcollection: " << cmdObj;
audit::logShardCollection(
opCtx->getClient(), nss.ns(), prerequisites.shardKeyPattern.toBSON(), request.getUnique());
const auto shardRegistry = Grid::get(opCtx)->shardRegistry();
const auto primaryShard = uassertStatusOK(shardRegistry->getShard(opCtx, dbPrimaryShardId));
// Record start in changelog
{
BSONObjBuilder collectionDetail;
collectionDetail.append("shardKey", prerequisites.shardKeyPattern.toBSON());
collectionDetail.append("collection", nss.ns());
prerequisites.uuid.appendToBuilder(&collectionDetail, "uuid");
collectionDetail.append("empty", prerequisites.collectionIsEmpty);
collectionDetail.append("fromMapReduce", prerequisites.fromMapReduce);
collectionDetail.append("primary", primaryShard->toString());
collectionDetail.append("numChunks",
static_cast<int>(prerequisites.splitPoints.size() + 1));
uassertStatusOK(ShardingLogging::get(opCtx)->logChangeChecked(
opCtx,
"shardCollection.start",
nss.ns(),
collectionDetail.obj(),
ShardingCatalogClient::kMajorityWriteConcern));
}
}
void createCollectionOnShardsReceivingChunks(OperationContext* opCtx,
const NamespaceString& nss,
const std::vector<ChunkType>& initialChunks,
const ShardId& dbPrimaryShardId) {
std::vector<AsyncRequestsSender::Request> requests;
std::set<ShardId> initializedShards;
for (const auto& chunk : initialChunks) {
const auto& chunkShardId = chunk.getShard();
if (chunkShardId == dbPrimaryShardId ||
initializedShards.find(chunkShardId) != initializedShards.end()) {
continue;
}
CloneCollectionOptionsFromPrimaryShard cloneCollectionOptionsFromPrimaryShardRequest(nss);
cloneCollectionOptionsFromPrimaryShardRequest.setPrimaryShard(dbPrimaryShardId.toString());
cloneCollectionOptionsFromPrimaryShardRequest.setDbName(nss.db());
requests.emplace_back(
chunkShardId,
cloneCollectionOptionsFromPrimaryShardRequest.toBSON(
BSON("writeConcern" << ShardingCatalogClient::kMajorityWriteConcern.toBSON())));
initializedShards.emplace(chunkShardId);
}
if (!requests.empty()) {
auto responses = gatherResponses(opCtx,
nss.db(),
ReadPreferenceSetting(ReadPreference::PrimaryOnly),
Shard::RetryPolicy::kIdempotent,
requests);
// If any shards fail to create the collection, fail the entire shardCollection command
// (potentially leaving incomplely created sharded collection)
for (const auto& response : responses) {
auto shardResponse = uassertStatusOKWithContext(
std::move(response.swResponse),
str::stream() << "Unable to create collection on " << response.shardId);
auto status = getStatusFromCommandResult(shardResponse.data);
uassertStatusOK(status.withContext(str::stream() << "Unable to create collection on "
<< response.shardId));
auto wcStatus = getWriteConcernStatusFromCommandResult(shardResponse.data);
uassertStatusOK(wcStatus.withContext(str::stream() << "Unable to create collection on "
<< response.shardId));
}
}
}
void writeFirstChunksToConfig(OperationContext* opCtx,
const InitialSplitPolicy::ShardCollectionConfig& initialChunks) {
std::vector<BSONObj> chunkObjs;
chunkObjs.reserve(initialChunks.chunks.size());
for (const auto& chunk : initialChunks.chunks) {
chunkObjs.push_back(chunk.toConfigBSON());
}
Grid::get(opCtx)->catalogClient()->insertConfigDocumentsAsRetryableWrite(
opCtx,
ChunkType::ConfigNS,
std::move(chunkObjs),
ShardingCatalogClient::kMajorityWriteConcern);
}
void updateShardingCatalogEntryForCollection(
OperationContext* opCtx,
const NamespaceString& nss,
const ShardCollectionTargetState& prerequisites,
const InitialSplitPolicy::ShardCollectionConfig& initialChunks,
const BSONObj& defaultCollation,
const bool unique) {
// Construct the collection default collator.
std::unique_ptr<CollatorInterface> defaultCollator;
if (!defaultCollation.isEmpty()) {
defaultCollator = uassertStatusOK(CollatorFactoryInterface::get(opCtx->getServiceContext())
->makeFromBSON(defaultCollation));
}
CollectionType coll;
coll.setNs(nss);
coll.setUUID(prerequisites.uuid);
coll.setEpoch(initialChunks.collVersion().epoch());
coll.setUpdatedAt(Date_t::fromMillisSinceEpoch(initialChunks.collVersion().toLong()));
coll.setKeyPattern(prerequisites.shardKeyPattern.toBSON());
coll.setDefaultCollation(defaultCollator ? defaultCollator->getSpec().toBSON() : BSONObj());
coll.setUnique(unique);
coll.setDistributionMode(CollectionType::DistributionMode::kSharded);
uassertStatusOK(ShardingCatalogClientImpl::updateShardingCatalogEntryForCollection(
opCtx, nss, coll, true /*upsert*/));
}
void refreshAllShards(OperationContext* opCtx,
const NamespaceString& nss,
const ShardId& dbPrimaryShardId,
const std::vector<ChunkType>& initialChunks) {
forceShardFilteringMetadataRefresh(opCtx, nss);
auto shardRegistry = Grid::get(opCtx)->shardRegistry();
std::set<ShardId> shardsRefreshed;
for (const auto& chunk : initialChunks) {
const auto& chunkShardId = chunk.getShard();
if (chunkShardId == dbPrimaryShardId ||
shardsRefreshed.find(chunkShardId) != shardsRefreshed.end()) {
continue;
}
auto shard = uassertStatusOK(shardRegistry->getShard(opCtx, chunkShardId));
auto refreshCmdResponse = uassertStatusOK(shard->runCommandWithFixedRetryAttempts(
opCtx,
ReadPreferenceSetting{ReadPreference::PrimaryOnly},
"admin",
BSON("_flushRoutingTableCacheUpdates" << nss.ns()),
Seconds{30},
Shard::RetryPolicy::kIdempotent));
uassertStatusOK(refreshCmdResponse.commandStatus);
shardsRefreshed.emplace(chunkShardId);
}
}
UUID shardCollection(OperationContext* opCtx,
const NamespaceString& nss,
const BSONObj& cmdObj,
const ShardsvrShardCollection& request,
const ShardId& dbPrimaryShardId) {
if (auto collectionOptional =
InitialSplitPolicy::checkIfCollectionAlreadyShardedWithSameOptions(
opCtx, nss, request, repl::ReadConcernLevel::kMajorityReadConcern)) {
uassert(ErrorCodes::InvalidUUID,
str::stream() << "Collection " << nss << " is sharded without UUID",
collectionOptional->getUUID());
return *collectionOptional->getUUID();
}
InitialSplitPolicy::ShardingOptimizationType optimizationType;
InitialSplitPolicy::ShardCollectionConfig initialChunks;
boost::optional<ShardCollectionTargetState> targetState;
auto writeChunkDocumentsAndRefreshShards =
[&](const ShardCollectionTargetState& targetState,
const InitialSplitPolicy::ShardCollectionConfig& initialChunks) {
// Insert chunk documents to config.chunks on the config server.
writeFirstChunksToConfig(opCtx, initialChunks);
updateShardingCatalogEntryForCollection(opCtx,
nss,
targetState,
initialChunks,
*request.getCollation(),
request.getUnique());
refreshAllShards(opCtx, nss, dbPrimaryShardId, initialChunks.chunks);
};
{
// From this point onward the collection can only be read, not written to, so it is safe to
// construct the prerequisites and generate the target state.
CollectionCriticalSection critSec(opCtx, nss);
if (auto collectionOptional =
InitialSplitPolicy::checkIfCollectionAlreadyShardedWithSameOptions(
opCtx, nss, request, repl::ReadConcernLevel::kMajorityReadConcern)) {
uassert(ErrorCodes::InvalidUUID,
str::stream() << "Collection " << nss << " is sharded without UUID",
collectionOptional->getUUID());
return *collectionOptional->getUUID();
}
targetState = calculateTargetState(opCtx, nss, request);
// From this point onward, the collection can not be written to or read from.
critSec.enterCommitPhase();
logStartShardCollection(opCtx, cmdObj, nss, request, *targetState, dbPrimaryShardId);
optimizationType = InitialSplitPolicy::calculateOptimizationType(
targetState->splitPoints, targetState->tags, targetState->collectionIsEmpty);
if (optimizationType != InitialSplitPolicy::ShardingOptimizationType::None) {
initialChunks = InitialSplitPolicy::createFirstChunksOptimized(
opCtx,
nss,
targetState->shardKeyPattern,
dbPrimaryShardId,
targetState->splitPoints,
targetState->tags,
optimizationType,
targetState->collectionIsEmpty,
targetState->numContiguousChunksPerShard);
// If we are coming from mapReduce, we will have created chunks with a distribution
// such that all reduce writes end up being local. In that case, we do not need to
// create the chunk on other shards.
if (!targetState->fromMapReduce) {
createCollectionOnShardsReceivingChunks(
opCtx, nss, initialChunks.chunks, dbPrimaryShardId);
}
writeChunkDocumentsAndRefreshShards(*targetState, initialChunks);
}
}
// We have now left the critical section.
if (optimizationType == InitialSplitPolicy::ShardingOptimizationType::None) {
invariant(initialChunks.chunks.empty());
initialChunks = InitialSplitPolicy::createFirstChunksUnoptimized(
opCtx, nss, targetState->shardKeyPattern, dbPrimaryShardId);
writeChunkDocumentsAndRefreshShards(*targetState, initialChunks);
}
LOG(0) << "Created " << initialChunks.chunks.size() << " chunk(s) for: " << nss
<< ", producing collection version " << initialChunks.collVersion();
ShardingLogging::get(opCtx)->logChange(
opCtx,
"shardCollection.end",
nss.ns(),
BSON("version" << initialChunks.collVersion().toString()),
ShardingCatalogClient::kMajorityWriteConcern);
return targetState->uuid;
}
/**
* Internal sharding command run on primary shard server to shard a collection.
*/
class ShardsvrShardCollectionCommand : public BasicCommand {
public:
ShardsvrShardCollectionCommand() : BasicCommand("_shardsvrShardCollection") {}
std::string help() const override {
return "should not be calling this directly";
}
AllowedOnSecondary secondaryAllowed(ServiceContext*) const override {
return AllowedOnSecondary::kNever;
}
bool adminOnly() const override {
return true;
}
bool supportsWriteConcern(const BSONObj& cmd) const override {
return true;
}
Status checkAuthForCommand(Client* client,
const std::string& dbname,
const BSONObj& cmdObj) const override {
if (!AuthorizationSession::get(client)->isAuthorizedForActionsOnResource(
ResourcePattern::forClusterResource(), ActionType::internal)) {
return Status(ErrorCodes::Unauthorized, "Unauthorized");
}
return Status::OK();
}
std::string parseNs(const std::string& dbname, const BSONObj& cmdObj) const override {
return CommandHelpers::parseNsFullyQualified(cmdObj);
}
bool run(OperationContext* opCtx,
const std::string& dbname,
const BSONObj& cmdObj,
BSONObjBuilder& result) override {
auto const shardingState = ShardingState::get(opCtx);
uassertStatusOK(shardingState->canAcceptShardedCommands());
const auto request = ShardsvrShardCollection::parse(
IDLParserErrorContext("_shardsvrShardCollection"), cmdObj);
const NamespaceString nss(parseNs(dbname, cmdObj));
auto scopedShardCollection = uassertStatusOK(
ActiveShardCollectionRegistry::get(opCtx).registerShardCollection(request));
OptionalCollectionUUID uuid;
// Check if this collection is currently being sharded and if so, join it
if (!scopedShardCollection.mustExecute()) {
uuid = scopedShardCollection.getUUID().get();
} else {
try {
uuid = shardCollection(
opCtx, nss, cmdObj, request, ShardingState::get(opCtx)->shardId());
} catch (const DBException& e) {
scopedShardCollection.emplaceUUID(e.toStatus());
throw;
} catch (const std::exception& e) {
scopedShardCollection.emplaceUUID(
{ErrorCodes::InternalError,
str::stream()
<< "Severe error occurred while running shardCollection command: "
<< e.what()});
throw;
}
uassert(ErrorCodes::InvalidUUID,
str::stream() << "Collection " << nss << " is sharded without UUID",
uuid);
scopedShardCollection.emplaceUUID(uuid);
}
result << "collectionsharded" << nss.ns();
result << "collectionUUID" << *uuid;
return true;
}
} shardsvrShardCollectionCmd;
} // namespace
} // namespace mongo
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