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/**
* Copyright (C) 2018 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/db/s/shard_filtering_metadata_refresh.h"
#include "mongo/db/catalog/database_holder.h"
#include "mongo/db/catalog_raii.h"
#include "mongo/db/commands/feature_compatibility_version.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/s/collection_sharding_state.h"
#include "mongo/db/s/database_sharding_state.h"
#include "mongo/db/s/operation_sharding_state.h"
#include "mongo/db/s/sharding_state.h"
#include "mongo/db/s/sharding_statistics.h"
#include "mongo/s/catalog_cache.h"
#include "mongo/s/grid.h"
#include "mongo/util/log.h"
namespace mongo {
Status onShardVersionMismatch(OperationContext* opCtx,
const NamespaceString& nss,
ChunkVersion shardVersionReceived) noexcept {
invariant(!opCtx->lockState()->isLocked());
invariant(!opCtx->getClient()->isInDirectClient());
auto const shardingState = ShardingState::get(opCtx);
invariant(shardingState->canAcceptShardedCommands());
LOG(2) << "Metadata refresh requested for " << nss.ns() << " at shard version "
<< shardVersionReceived;
ShardingStatistics::get(opCtx).countStaleConfigErrors.addAndFetch(1);
// Ensure any ongoing migrations have completed before trying to do the refresh. This wait is
// just an optimization so that MongoS does not exhaust its maximum number of StaleConfig retry
// attempts while the migration is being committed.
try {
auto& oss = OperationShardingState::get(opCtx);
oss.waitForMigrationCriticalSectionSignal(opCtx);
} catch (const DBException& ex) {
return ex.toStatus();
}
const auto currentShardVersion = [&] {
AutoGetCollection autoColl(opCtx, nss, MODE_IS);
const auto currentMetadata = CollectionShardingState::get(opCtx, nss)->getMetadata(opCtx);
if (currentMetadata) {
return currentMetadata->getShardVersion();
}
return ChunkVersion::UNSHARDED();
}();
if (currentShardVersion.epoch() == shardVersionReceived.epoch() &&
currentShardVersion.majorVersion() >= shardVersionReceived.majorVersion()) {
// Don't need to remotely reload if we're in the same epoch and the requested version is
// smaller than the one we know about. This means that the remote side is behind.
return Status::OK();
}
try {
forceShardFilteringMetadataRefresh(opCtx, nss);
return Status::OK();
} catch (const DBException& ex) {
log() << "Failed to refresh metadata for collection" << nss << causedBy(redact(ex));
return ex.toStatus();
}
}
ChunkVersion forceShardFilteringMetadataRefresh(OperationContext* opCtx,
const NamespaceString& nss) {
invariant(!opCtx->lockState()->isLocked());
invariant(!opCtx->getClient()->isInDirectClient());
auto const shardingState = ShardingState::get(opCtx);
invariant(shardingState->canAcceptShardedCommands());
const auto routingInfo = uassertStatusOK(
Grid::get(opCtx)->catalogCache()->getCollectionRoutingInfoWithRefresh(opCtx, nss));
const 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);
auto css = CollectionShardingState::get(opCtx, nss);
css->refreshMetadata(opCtx, nullptr);
return ChunkVersion::UNSHARDED();
}
{
AutoGetCollection autoColl(opCtx, nss, MODE_IS);
auto metadata = CollectionShardingState::get(opCtx, nss)->getMetadata(opCtx);
// We already have newer version
if (metadata && 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 css = CollectionShardingState::get(opCtx, nss);
auto metadata = css->getMetadata(opCtx);
// We already have newer version
if (metadata && 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();
}
std::unique_ptr<CollectionMetadata> newCollectionMetadata =
stdx::make_unique<CollectionMetadata>(cm, shardingState->getShardName());
css->refreshMetadata(opCtx, std::move(newCollectionMetadata));
return css->getMetadata(opCtx)->getShardVersion();
}
void onDbVersionMismatch(OperationContext* opCtx,
const StringData dbName,
const DatabaseVersion& clientDbVersion,
const boost::optional<DatabaseVersion>& serverDbVersion) noexcept {
invariant(!opCtx->lockState()->isLocked());
invariant(!opCtx->getClient()->isInDirectClient());
auto const shardingState = ShardingState::get(opCtx);
invariant(shardingState->canAcceptShardedCommands());
if (serverDbVersion && serverDbVersion->getUuid() == clientDbVersion.getUuid() &&
serverDbVersion->getLastMod() >= clientDbVersion.getLastMod()) {
// The client was stale; do not trigger server-side refresh.
return;
}
try {
// TODO SERVER-33773 if the 'waitForMovePrimaryCriticalSection' flag is set on the
// OperationShardingState, wait for the movePrimary critical section to complete before
// attempting a refresh.
} catch (const DBException& ex) {
log() << "Failed to wait for movePrimary critical section to complete "
<< causedBy(redact(ex));
return;
}
try {
forceDatabaseRefresh(opCtx, dbName);
} catch (const DBException& ex) {
log() << "Failed to refresh databaseVersion for database " << dbName
<< causedBy(redact(ex));
}
}
void forceDatabaseRefresh(OperationContext* opCtx, const StringData dbName) {
invariant(!opCtx->lockState()->isLocked());
invariant(!opCtx->getClient()->isInDirectClient());
auto const shardingState = ShardingState::get(opCtx);
invariant(shardingState->canAcceptShardedCommands());
const auto refreshedDbVersion =
uassertStatusOK(Grid::get(opCtx)->catalogCache()->getDatabaseWithRefresh(opCtx, dbName))
.databaseVersion();
// Only set the in-memory version in FCV 4.0, and hold the lock across checking the FCV and
// setting the version.
Lock::SharedLock lk(opCtx->lockState(), FeatureCompatibilityVersion::fcvLock);
if (serverGlobalParams.featureCompatibility.getVersion() ==
ServerGlobalParams::FeatureCompatibility::Version::kFullyUpgradedTo40) {
// First, check under a shared lock if another thread already updated the cached version.
// This is a best-effort optimization to make as few threads as possible to convoy on the
// exclusive lock below.
{
// Take the DBLock directly rather than using AutoGetDb, to prevent a recursive call
// into checkDbVersion().
Lock::DBLock dbLock(opCtx, dbName, MODE_IS);
const auto db = DatabaseHolder::getDatabaseHolder().get(opCtx, dbName);
if (!db) {
log() << "Database " << dbName
<< " has been dropped; not caching the refreshed databaseVersion";
return;
}
const auto cachedDbVersion = DatabaseShardingState::get(db).getDbVersion(opCtx);
if (cachedDbVersion && refreshedDbVersion &&
cachedDbVersion->getUuid() == refreshedDbVersion->getUuid() &&
cachedDbVersion->getLastMod() >= refreshedDbVersion->getLastMod()) {
LOG(2) << "Skipping setting cached databaseVersion for " << dbName
<< " to refreshed version " << refreshedDbVersion->toBSON()
<< " because current cached databaseVersion is already "
<< cachedDbVersion->toBSON();
return;
}
}
// The cached version is older than the refreshed version; update the cached version.
Lock::DBLock dbLock(opCtx, dbName, MODE_X);
const auto db = DatabaseHolder::getDatabaseHolder().get(opCtx, dbName);
if (!db) {
log() << "Database " << dbName
<< " has been dropped; not caching the refreshed databaseVersion";
return;
}
DatabaseShardingState::get(db).setDbVersion(opCtx, std::move(refreshedDbVersion));
}
}
} // namespace mongo
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