rocksdb/db/in_memory_stats_history.cc
Zhongyi Xie c4f5d0aa15 add GetStatsHistory to retrieve stats snapshots (#4748)
Summary:
This PR adds public `GetStatsHistory` API to retrieve stats history in the form of an std map. The key of the map is the timestamp in microseconds when the stats snapshot is taken, the value is another std map from stats name to stats value (stored in std string). Two DBOptions are introduced: `stats_persist_period_sec` (default 10 minutes) controls the intervals between two snapshots are taken; `max_stats_history_count` (default 10) controls the max number of history snapshots to keep in memory. RocksDB will stop collecting stats snapshots if `stats_persist_period_sec` is set to 0.

(This PR is the in-memory part of https://github.com/facebook/rocksdb/pull/4535)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4748

Differential Revision: D13961471

Pulled By: miasantreble

fbshipit-source-id: ac836d401ecb84ea92216bf9966f969dedf4ad04
2019-02-20 15:52:54 -08:00

46 lines
1.6 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/db_impl.h"
#include "db/in_memory_stats_history.h"
namespace rocksdb {
InMemoryStatsHistoryIterator::~InMemoryStatsHistoryIterator() {}
bool InMemoryStatsHistoryIterator::Valid() const { return valid_; }
Status InMemoryStatsHistoryIterator::status() const { return status_; }
void InMemoryStatsHistoryIterator::Next() {
// increment start_time by 1 to avoid infinite loop
AdvanceIteratorByTime(GetStatsTime() + 1, end_time_);
}
uint64_t InMemoryStatsHistoryIterator::GetStatsTime() const { return time_; }
const std::map<std::string, uint64_t>&
InMemoryStatsHistoryIterator::GetStatsMap() const {
return stats_map_;
}
// advance the iterator to the next time between [start_time, end_time)
// if success, update time_ and stats_map_ with new_time and stats_map
void InMemoryStatsHistoryIterator::AdvanceIteratorByTime(uint64_t start_time,
uint64_t end_time) {
// try to find next entry in stats_history_ map
if (db_impl_ != nullptr) {
valid_ =
db_impl_->FindStatsByTime(start_time, end_time, &time_, &stats_map_);
} else {
valid_ = false;
}
}
} // namespace rocksdb