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/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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/s/catalog_cache.h"
#include "mongo/base/status.h"
#include "mongo/base/status_with.h"
#include "mongo/db/query/collation/collator_factory_interface.h"
#include "mongo/db/repl/optime_with.h"
#include "mongo/platform/unordered_set.h"
#include "mongo/s/catalog/sharding_catalog_client.h"
#include "mongo/s/catalog/type_collection.h"
#include "mongo/s/catalog/type_database.h"
#include "mongo/s/client/shard_registry.h"
#include "mongo/s/grid.h"
#include "mongo/util/log.h"
#include "mongo/util/timer.h"
namespace mongo {
namespace {
// How many times to try refreshing the routing info if the set of chunks loaded from the config
// server is found to be inconsistent.
const int kMaxInconsistentRoutingInfoRefreshAttempts = 3;
/**
* Given an (optional) initial routing table and a set of changed chunks returned by the catalog
* cache loader, produces a new routing table with the changes applied.
*
* If the collection is no longer sharded returns nullptr. If the epoch has changed, expects that
* the 'collectionChunksList' contains the full contents of the chunks collection for that namespace
* so that the routing table can be built from scratch.
*
* Throws ConflictingOperationInProgress if the chunk metadata was found to be inconsistent (not
* containing all the necessary chunks, contains overlaps or chunks' epoch values are not the same
* as that of the collection). Since this situation may be transient, due to the collection being
* dropped or recreated concurrently, the caller must retry the reload up to some configurable
* number of attempts.
*/
std::shared_ptr<ChunkManager> refreshCollectionRoutingInfo(
OperationContext* opCtx,
const NamespaceString& nss,
std::shared_ptr<ChunkManager> existingRoutingInfo,
StatusWith<CatalogCacheLoader::CollectionAndChangedChunks> swCollectionAndChangedChunks) {
if (swCollectionAndChangedChunks == ErrorCodes::NamespaceNotFound) {
return nullptr;
}
const auto collectionAndChunks = uassertStatusOK(std::move(swCollectionAndChangedChunks));
auto chunkManager = [&] {
// If we have routing info already and it's for the same collection epoch, we're updating.
// Otherwise, we're making a whole new routing table.
if (existingRoutingInfo &&
existingRoutingInfo->getVersion().epoch() == collectionAndChunks.epoch) {
return existingRoutingInfo->makeUpdated(collectionAndChunks.changedChunks);
}
auto defaultCollator = [&]() -> std::unique_ptr<CollatorInterface> {
if (!collectionAndChunks.defaultCollation.isEmpty()) {
// The collation should have been validated upon collection creation
return uassertStatusOK(CollatorFactoryInterface::get(opCtx->getServiceContext())
->makeFromBSON(collectionAndChunks.defaultCollation));
}
return nullptr;
}();
return ChunkManager::makeNew(nss,
KeyPattern(collectionAndChunks.shardKeyPattern),
std::move(defaultCollator),
collectionAndChunks.shardKeyIsUnique,
collectionAndChunks.epoch,
collectionAndChunks.changedChunks);
}();
std::set<ShardId> shardIds;
chunkManager->getAllShardIds(&shardIds);
for (const auto& shardId : shardIds) {
uassertStatusOK(Grid::get(opCtx)->shardRegistry()->getShard(opCtx, shardId));
}
return chunkManager;
}
} // namespace
CatalogCache::CatalogCache(CatalogCacheLoader& cacheLoader) : _cacheLoader(cacheLoader) {}
CatalogCache::~CatalogCache() = default;
StatusWith<CachedDatabaseInfo> CatalogCache::getDatabase(OperationContext* opCtx,
StringData dbName) {
try {
return {CachedDatabaseInfo(_getDatabase(opCtx, dbName))};
} catch (const DBException& ex) {
return ex.toStatus();
}
}
StatusWith<CachedCollectionRoutingInfo> CatalogCache::getCollectionRoutingInfo(
OperationContext* opCtx, const NamespaceString& nss) {
while (true) {
std::shared_ptr<DatabaseInfoEntry> dbEntry;
try {
dbEntry = _getDatabase(opCtx, nss.db());
} catch (const DBException& ex) {
return ex.toStatus();
}
stdx::unique_lock<stdx::mutex> ul(_mutex);
auto& collections = dbEntry->collections;
auto it = collections.find(nss.ns());
if (it == collections.end()) {
auto shardStatus =
Grid::get(opCtx)->shardRegistry()->getShard(opCtx, dbEntry->primaryShardId);
if (!shardStatus.isOK()) {
return {ErrorCodes::fromInt(40371),
str::stream() << "The primary shard for collection " << nss.ns()
<< " could not be loaded due to error "
<< shardStatus.getStatus().toString()};
}
return {CachedCollectionRoutingInfo(
dbEntry->primaryShardId, nss, std::move(shardStatus.getValue()))};
}
auto& collEntry = it->second;
if (collEntry.needsRefresh) {
auto refreshNotification = collEntry.refreshCompletionNotification;
if (!refreshNotification) {
refreshNotification = (collEntry.refreshCompletionNotification =
std::make_shared<Notification<Status>>());
_scheduleCollectionRefresh_inlock(
dbEntry, std::move(collEntry.routingInfo), nss, 1);
}
// Wait on the notification outside of the mutex
ul.unlock();
auto refreshStatus = [&]() {
try {
return refreshNotification->get(opCtx);
} catch (const DBException& ex) {
return ex.toStatus();
}
}();
if (!refreshStatus.isOK()) {
return refreshStatus;
}
// Once the refresh is complete, loop around to get the latest value
continue;
}
return {CachedCollectionRoutingInfo(dbEntry->primaryShardId, collEntry.routingInfo)};
}
}
StatusWith<CachedCollectionRoutingInfo> CatalogCache::getCollectionRoutingInfo(
OperationContext* opCtx, StringData ns) {
return getCollectionRoutingInfo(opCtx, NamespaceString(ns));
}
StatusWith<CachedCollectionRoutingInfo> CatalogCache::getShardedCollectionRoutingInfoWithRefresh(
OperationContext* opCtx, const NamespaceString& nss) {
invalidateShardedCollection(nss);
auto routingInfoStatus = getCollectionRoutingInfo(opCtx, nss);
if (routingInfoStatus.isOK() && !routingInfoStatus.getValue().cm()) {
return {ErrorCodes::NamespaceNotSharded,
str::stream() << "Collection " << nss.ns() << " is not sharded."};
}
return routingInfoStatus;
}
StatusWith<CachedCollectionRoutingInfo> CatalogCache::getShardedCollectionRoutingInfoWithRefresh(
OperationContext* opCtx, StringData ns) {
return getShardedCollectionRoutingInfoWithRefresh(opCtx, NamespaceString(ns));
}
void CatalogCache::onStaleConfigError(CachedCollectionRoutingInfo&& ccriToInvalidate) {
// Ensure the move constructor of CachedCollectionRoutingInfo is invoked in order to clear the
// input argument so it can't be used anymore
auto ccri(ccriToInvalidate);
if (!ccri._cm) {
// Here we received a stale config error for a collection which we previously thought was
// unsharded.
invalidateShardedCollection(ccri._nss);
return;
}
// Here we received a stale config error for a collection which we previously though was sharded
stdx::lock_guard<stdx::mutex> lg(_mutex);
auto it = _databases.find(NamespaceString(ccri._cm->getns()).db());
if (it == _databases.end()) {
// If the database does not exist, the collection must have been dropped so there is
// nothing to invalidate. The getCollectionRoutingInfo will handle the reload of the
// entire database and its collections.
return;
}
auto& collections = it->second->collections;
auto itColl = collections.find(ccri._cm->getns());
if (itColl == collections.end()) {
// If the collection does not exist, this means it must have been dropped since the last
// time we retrieved a cache entry for it. Doing nothing in this case will cause the
// next call to getCollectionRoutingInfo to return an unsharded collection.
return;
} else if (itColl->second.needsRefresh) {
// Refresh has been scheduled for the collection already
return;
} else if (itColl->second.routingInfo->getVersion() == ccri._cm->getVersion()) {
// If the versions match, the last version of the routing information that we used is no
// longer valid, so trigger a refresh.
itColl->second.needsRefresh = true;
}
}
void CatalogCache::invalidateShardedCollection(const NamespaceString& nss) {
stdx::lock_guard<stdx::mutex> lg(_mutex);
auto it = _databases.find(nss.db());
if (it == _databases.end()) {
return;
}
it->second->collections[nss.ns()].needsRefresh = true;
}
void CatalogCache::invalidateShardedCollection(StringData ns) {
invalidateShardedCollection(NamespaceString(ns));
}
void CatalogCache::purgeDatabase(StringData dbName) {
stdx::lock_guard<stdx::mutex> lg(_mutex);
_databases.erase(dbName);
}
void CatalogCache::purgeAllDatabases() {
stdx::lock_guard<stdx::mutex> lg(_mutex);
_databases.clear();
}
std::shared_ptr<CatalogCache::DatabaseInfoEntry> CatalogCache::_getDatabase(OperationContext* opCtx,
StringData dbName) {
stdx::lock_guard<stdx::mutex> lg(_mutex);
auto it = _databases.find(dbName);
if (it != _databases.end()) {
return it->second;
}
const auto catalogClient = Grid::get(opCtx)->catalogClient();
const auto dbNameCopy = dbName.toString();
// Load the database entry
const auto opTimeWithDb = uassertStatusOK(catalogClient->getDatabase(opCtx, dbNameCopy));
const auto& dbDesc = opTimeWithDb.value;
// Load the sharded collections entries
std::vector<CollectionType> collections;
repl::OpTime collLoadConfigOptime;
uassertStatusOK(
catalogClient->getCollections(opCtx, &dbNameCopy, &collections, &collLoadConfigOptime));
StringMap<CollectionRoutingInfoEntry> collectionEntries;
for (const auto& coll : collections) {
if (coll.getDropped()) {
continue;
}
collectionEntries[coll.getNs().ns()].needsRefresh = true;
}
return _databases[dbName] = std::shared_ptr<DatabaseInfoEntry>(new DatabaseInfoEntry{
dbDesc.getPrimary(), dbDesc.getSharded(), std::move(collectionEntries)});
}
void CatalogCache::_scheduleCollectionRefresh_inlock(
std::shared_ptr<DatabaseInfoEntry> dbEntry,
std::shared_ptr<ChunkManager> existingRoutingInfo,
const NamespaceString& nss,
int refreshAttempt) {
Timer t;
const ChunkVersion startingCollectionVersion =
(existingRoutingInfo ? existingRoutingInfo->getVersion() : ChunkVersion::UNSHARDED());
const auto refreshFailed_inlock =
[ this, t, dbEntry, nss, refreshAttempt ](const Status& status) noexcept {
log() << "Refresh for collection " << nss << " took " << t.millis() << " ms and failed"
<< causedBy(redact(status));
auto& collections = dbEntry->collections;
auto it = collections.find(nss.ns());
invariant(it != collections.end());
auto& collEntry = it->second;
// It is possible that the metadata is being changed concurrently, so retry the
// refresh again
if (status == ErrorCodes::ConflictingOperationInProgress &&
refreshAttempt < kMaxInconsistentRoutingInfoRefreshAttempts) {
_scheduleCollectionRefresh_inlock(dbEntry, nullptr, nss, refreshAttempt + 1);
} else {
// Leave needsRefresh to true so that any subsequent get attempts will kick off
// another round of refresh
collEntry.refreshCompletionNotification->set(status);
collEntry.refreshCompletionNotification = nullptr;
}
};
const auto refreshCallback =
[ this, t, dbEntry, nss, existingRoutingInfo, refreshFailed_inlock ](
OperationContext * opCtx,
StatusWith<CatalogCacheLoader::CollectionAndChangedChunks> swCollAndChunks) noexcept {
std::shared_ptr<ChunkManager> newRoutingInfo;
try {
newRoutingInfo = refreshCollectionRoutingInfo(
opCtx, nss, std::move(existingRoutingInfo), std::move(swCollAndChunks));
} catch (const DBException& ex) {
stdx::lock_guard<stdx::mutex> lg(_mutex);
refreshFailed_inlock(ex.toStatus());
return;
}
stdx::lock_guard<stdx::mutex> lg(_mutex);
auto& collections = dbEntry->collections;
auto it = collections.find(nss.ns());
invariant(it != collections.end());
auto& collEntry = it->second;
collEntry.needsRefresh = false;
collEntry.refreshCompletionNotification->set(Status::OK());
collEntry.refreshCompletionNotification = nullptr;
if (!newRoutingInfo) {
log() << "Refresh for collection " << nss << " took " << t.millis()
<< " and found the collection is not sharded";
collections.erase(it);
} else {
log() << "Refresh for collection " << nss << " took " << t.millis()
<< " ms and found version " << newRoutingInfo->getVersion();
collEntry.routingInfo = std::move(newRoutingInfo);
}
};
log() << "Refreshing chunks for collection " << nss << " based on version "
<< startingCollectionVersion;
try {
_cacheLoader.getChunksSince(nss, startingCollectionVersion, refreshCallback);
} catch (const DBException& ex) {
const auto status = ex.toStatus();
// ConflictingOperationInProgress errors trigger retry of the catalog cache reload logic. If
// we failed to schedule the asynchronous reload, there is no point in doing another
// attempt.
invariant(status != ErrorCodes::ConflictingOperationInProgress);
stdx::lock_guard<stdx::mutex> lg(_mutex);
refreshFailed_inlock(status);
}
}
CachedDatabaseInfo::CachedDatabaseInfo(std::shared_ptr<CatalogCache::DatabaseInfoEntry> db)
: _db(std::move(db)) {}
const ShardId& CachedDatabaseInfo::primaryId() const {
return _db->primaryShardId;
}
bool CachedDatabaseInfo::shardingEnabled() const {
return _db->shardingEnabled;
}
CachedCollectionRoutingInfo::CachedCollectionRoutingInfo(ShardId primaryId,
std::shared_ptr<ChunkManager> cm)
: _primaryId(std::move(primaryId)), _cm(std::move(cm)) {}
CachedCollectionRoutingInfo::CachedCollectionRoutingInfo(ShardId primaryId,
NamespaceString nss,
std::shared_ptr<Shard> primary)
: _primaryId(std::move(primaryId)), _nss(std::move(nss)), _primary(std::move(primary)) {}
} // namespace mongo
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