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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.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/keys_collection_cache.h"
#include "mongo/db/keys_collection_client.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/util/str.h"
namespace mongo {
KeysCollectionCache::KeysCollectionCache(std::string purpose, KeysCollectionClient* client)
: _purpose(std::move(purpose)), _client(client) {}
StatusWith<KeysCollectionDocument> KeysCollectionCache::refresh(OperationContext* opCtx) {
// Don't allow this to read during initial sync because it will read at the initialDataTimestamp
// and that could conflict with reconstructing prepared transactions using the
// initialDataTimestamp as the prepareTimestamp.
if (repl::ReplicationCoordinator::get(opCtx) &&
repl::ReplicationCoordinator::get(opCtx)->getMemberState().startup2()) {
return {ErrorCodes::InitialSyncActive,
"Cannot refresh keys collection cache during initial sync"};
}
// Don't allow this to read during rollback as the storage engine requires exclusive access.
if (repl::ReplicationCoordinator::get(opCtx) &&
repl::ReplicationCoordinator::get(opCtx)->getMemberState().rollback()) {
return {ErrorCodes::InterruptedDueToReplStateChange,
"Cannot refresh keys collection cache during rollback"};
}
auto refreshStatus = _refreshExternalKeys(opCtx);
if (!refreshStatus.isOK()) {
return refreshStatus;
}
return _refreshInternalKeys(opCtx);
}
StatusWith<KeysCollectionDocument> KeysCollectionCache::_refreshInternalKeys(
OperationContext* opCtx) {
LogicalTime newerThanThis;
decltype(_internalKeysCache)::size_type originalSize = 0;
{
stdx::lock_guard<Latch> lk(_cacheMutex);
auto iter = _internalKeysCache.crbegin();
if (iter != _internalKeysCache.crend()) {
newerThanThis = iter->second.getExpiresAt();
}
originalSize = _internalKeysCache.size();
}
auto refreshStatus = _client->getNewInternalKeys(opCtx, _purpose, newerThanThis, true);
if (!refreshStatus.isOK()) {
return refreshStatus.getStatus();
}
auto& newKeys = refreshStatus.getValue();
stdx::lock_guard<Latch> lk(_cacheMutex);
if (originalSize > _internalKeysCache.size()) {
// _internalKeysCache cleared while we were getting the new keys, just return the newest key
// without touching the _internalKeysCache so the next refresh will populate it properly.
// Note: newKeys are sorted.
if (!newKeys.empty()) {
return std::move(newKeys.back());
}
}
for (auto&& key : newKeys) {
_internalKeysCache.emplace(std::make_pair(key.getExpiresAt(), std::move(key)));
}
if (_internalKeysCache.empty()) {
return {ErrorCodes::KeyNotFound, "No keys found after refresh"};
}
return _internalKeysCache.crbegin()->second;
}
Status KeysCollectionCache::_refreshExternalKeys(OperationContext* opCtx) {
decltype(_externalKeysCache)::size_type originalSize = 0;
{
stdx::lock_guard<Latch> lk(_cacheMutex);
originalSize = _externalKeysCache.size();
}
auto refreshStatus = _client->getAllExternalKeys(opCtx, _purpose);
if (!refreshStatus.isOK()) {
return refreshStatus.getStatus();
}
auto& newKeys = refreshStatus.getValue();
std::multimap<long long, ExternalKeysCollectionDocument> newExternalKeysCache;
for (auto&& key : newKeys) {
newExternalKeysCache.emplace(key.getKeyId(), std::move(key));
}
stdx::lock_guard<Latch> lk(_cacheMutex);
if (originalSize > _externalKeysCache.size()) {
// _externalKeysCache cleared while we were getting the new keys, just return so the next
// refresh will populate it properly.
return Status::OK();
}
// Replace the cached keys with the newly loaded ones. Note because all external keys are loaded
// when refreshing them, this will remove keys that have been deleted from the collection.
std::swap(_externalKeysCache, newExternalKeysCache);
return Status::OK();
}
StatusWith<KeysCollectionDocument> KeysCollectionCache::getInternalKeyById(
long long keyId, const LogicalTime& forThisTime) {
stdx::lock_guard<Latch> lk(_cacheMutex);
for (auto iter = _internalKeysCache.lower_bound(forThisTime); iter != _internalKeysCache.cend();
++iter) {
if (iter->second.getKeyId() == keyId) {
return iter->second;
}
}
return {ErrorCodes::KeyNotFound,
str::stream() << "Cache Reader No internal keys found for " << _purpose
<< " that is valid for time: " << forThisTime.toString()
<< " with id: " << keyId};
}
StatusWith<std::vector<ExternalKeysCollectionDocument>> KeysCollectionCache::getExternalKeysById(
long long keyId, const LogicalTime& forThisTime) {
stdx::lock_guard<Latch> lk(_cacheMutex);
std::vector<ExternalKeysCollectionDocument> keys;
if (_externalKeysCache.empty()) {
return {ErrorCodes::KeyNotFound,
str::stream() << "Cache Reader No external keys found for " << _purpose
<< " with id: " << keyId};
}
auto keysRange = _externalKeysCache.equal_range(keyId);
for (auto keyIter = keysRange.first; keyIter != keysRange.second; keyIter++) {
auto key = keyIter->second;
if (key.getExpiresAt() > forThisTime) {
keys.push_back(key);
}
}
if (keys.empty()) {
return {ErrorCodes::KeyNotFound,
str::stream() << "Cache Reader No external keys found for " << _purpose
<< " that is valid for time: " << forThisTime.toString()
<< " with id: " << keyId};
}
return std::move(keys);
}
StatusWith<KeysCollectionDocument> KeysCollectionCache::getInternalKey(
const LogicalTime& forThisTime) {
stdx::lock_guard<Latch> lk(_cacheMutex);
auto iter = _internalKeysCache.upper_bound(forThisTime);
if (iter == _internalKeysCache.cend()) {
return {ErrorCodes::KeyNotFound,
str::stream() << "No key found that is valid for " << forThisTime.toString()};
}
return iter->second;
}
void KeysCollectionCache::resetCache() {
// keys that read with non majority readConcern level can be rolled back.
if (!_client->supportsMajorityReads()) {
stdx::lock_guard<Latch> lk(_cacheMutex);
_internalKeysCache.clear();
_externalKeysCache.clear();
}
}
void KeysCollectionCache::cacheExternalKey(ExternalKeysCollectionDocument key) {
stdx::lock_guard<Latch> lk(_cacheMutex);
_externalKeysCache.emplace(key.getKeyId(), std::move(key));
}
} // namespace mongo
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