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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/db/collection_index_usage_tracker.h"
#include <atomic>
#include "mongo/db/commands/server_status_metric.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/clock_source.h"
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kStorage
namespace mongo {
namespace {
CounterMetric collectionScansCounter("queryExecutor.collectionScans.total");
CounterMetric collectionScansNonTailableCounter("queryExecutor.collectionScans.nonTailable");
} // namespace
CollectionIndexUsageTracker::CollectionIndexUsageTracker(
GlobalIndexUsageTracker* globalIndexUsageTracker, ClockSource* clockSource)
: _indexUsageStatsMap(std::make_shared<CollectionIndexUsageMap>()),
_clockSource(clockSource),
_globalIndexUsageTracker(globalIndexUsageTracker) {
invariant(_clockSource);
}
void CollectionIndexUsageTracker::recordIndexAccess(StringData indexName) {
invariant(!indexName.empty());
// The following update after fetching the map can race with the removal of this index entry
// from the map. However, that race is inconsequential and remains memory safe.
auto mapSharedPtr = atomic_load(&_indexUsageStatsMap);
auto it = mapSharedPtr->find(indexName);
if (it == mapSharedPtr->end()) {
// We are using an index that has been removed from the catalog, no need to track usage
return;
}
_globalIndexUsageTracker->onAccess(it->second->features);
// Increment the index usage atomic counter.
it->second->accesses.fetchAndAdd(1);
}
void CollectionIndexUsageTracker::recordCollectionScans(unsigned long long collectionScans) {
_collectionScans.fetchAndAdd(collectionScans);
collectionScansCounter.increment(collectionScans);
}
void CollectionIndexUsageTracker::recordCollectionScansNonTailable(
unsigned long long collectionScansNonTailable) {
_collectionScansNonTailable.fetchAndAdd(collectionScansNonTailable);
collectionScansNonTailableCounter.increment(collectionScansNonTailable);
}
void CollectionIndexUsageTracker::registerIndex(StringData indexName,
const BSONObj& indexKey,
const IndexFeatures& features) {
invariant(!indexName.empty());
// Create a copy of the map to modify.
auto mapSharedPtr = atomic_load(&_indexUsageStatsMap);
auto mapCopy = std::make_shared<CollectionIndexUsageMap>(*mapSharedPtr);
dassert(mapCopy->find(indexName) == mapCopy->end());
// Create the map entry.
auto inserted = mapCopy->try_emplace(
indexName, make_intrusive<IndexUsageStats>(_clockSource->now(), indexKey, features));
invariant(inserted.second);
_globalIndexUsageTracker->onRegister(inserted.first->second->features);
// Swap the modified map into place atomically.
atomic_store(&_indexUsageStatsMap, std::move(mapCopy));
}
void CollectionIndexUsageTracker::unregisterIndex(StringData indexName) {
invariant(!indexName.empty());
// Create a copy of the map to modify.
auto mapSharedPtr = atomic_load(&_indexUsageStatsMap);
auto mapCopy = std::make_shared<CollectionIndexUsageMap>(*mapSharedPtr);
auto it = mapCopy->find(indexName);
if (it != mapCopy->end()) {
_globalIndexUsageTracker->onUnregister(it->second->features);
// Remove the map entry.
mapCopy->erase(it);
// Swap the modified map into place atomically.
atomic_store(&_indexUsageStatsMap, std::move(mapCopy));
}
}
std::shared_ptr<CollectionIndexUsageTracker::CollectionIndexUsageMap>
CollectionIndexUsageTracker::getUsageStats() const {
return atomic_load(&_indexUsageStatsMap);
}
CollectionIndexUsageTracker::CollectionScanStats
CollectionIndexUsageTracker::getCollectionScanStats() const {
return {_collectionScans.load(), _collectionScansNonTailable.load()};
}
} // namespace mongo
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