Files
MaxScale/maxutils/maxbase/src/eventcount.cc
2018-06-25 10:07:52 +03:00

291 lines
7.2 KiB
C++

/*
* Copyright (c) 2018 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2022-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#include <maxbase/eventcount.hh>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <map>
namespace maxbase
{
EventCount::EventCount(const std::string& event_id, Duration time_window, Duration granularity) :
m_event_id(event_id),
m_time_window(time_window),
m_granularity(granularity.count())
{
increment();
}
void EventCount::increment()
{
using namespace std::chrono;
auto ticks = time_point_cast<nanoseconds>(Clock::now()).time_since_epoch().count();
if (m_granularity)
{
ticks = ticks / m_granularity * m_granularity;
}
if (m_timestamps.empty()
|| m_timestamps.back().time_point.time_since_epoch().count() != ticks)
{
m_timestamps.emplace_back(TimePoint(ticks), 1);
}
else
{
++m_timestamps.back().count;
}
}
namespace
{
struct TimePointLessEqual
{
TimePoint lhs;
TimePointLessEqual(TimePoint tp) : lhs(tp) {}
bool operator()(const EventCount::Timestamp& rhs) const
{
return lhs <= rhs.time_point;
}
bool operator()(TimePoint rhs) const
{
return lhs <= rhs;
}
};
}
void EventCount::purge() const
{
StopWatch sw;
auto windowBegin = Clock::now() - m_time_window;
auto ite = std::find_if(m_timestamps.begin(), m_timestamps.end(),
TimePointLessEqual(windowBegin));
m_timestamps.erase(m_timestamps.begin(), ite);
}
int EventCount::count() const
{
purge();
int count {0};
for (auto ite = m_timestamps.begin(); ite != m_timestamps.end(); ++ite)
{
count += ite->count;
}
return count;
}
void EventCount::dump(std::ostream &os) const
{
os << m_event_id << ": " << count() << " " << m_timestamps.size();
}
std::ostream& operator<<(std::ostream& os, const EventCount& EventCount)
{
EventCount.dump(os);
return os;
}
// Force a purge once in awhile, could be configurable. This is needed if
// a client generates lots of events but rarely reads them back (purges).
const int CleanupCountdown = 10000;
SessionCount::SessionCount(const std::string& sess_id, Duration time_window,
Duration granularity) :
m_sess_id(sess_id), m_time_window(time_window), m_granularity(granularity),
m_cleanup_countdown(CleanupCountdown)
{
}
const std::vector<EventCount> &SessionCount::event_counts() const
{
purge();
return m_event_counts;
}
bool SessionCount::empty() const
{
purge();
return m_event_counts.empty();
}
namespace
{
struct MatchEventId
{
std::string event_id;
MatchEventId(const std::string& id) : event_id(id) {};
bool operator()(const EventCount& stats) const
{
return event_id == stats.event_id();
}
};
}
void SessionCount::increment(const std::string& event_id)
{
// Always put the incremented entry (latest timestamp) last in the vector (using
// rotate). This means the vector is ordered so that expired entries are always first.
// Find in reverse, the entry is more likely to be towards the end. Actually no,
// for some reason the normal search is slightly faster when measured.
auto ite = find_if(m_event_counts.begin(), m_event_counts.end(),
MatchEventId(event_id));
if (ite == m_event_counts.end())
{
m_event_counts.emplace_back(event_id, m_time_window, m_granularity);
}
else
{
ite->increment();
// rotate so that the entry becomes the last one
auto next = std::next(ite);
std::rotate(ite, next, m_event_counts.end());
}
if (!--m_cleanup_countdown)
{
purge();
}
}
namespace
{
struct NonZeroEntry
{
bool operator()(const EventCount& stats)
{
return stats.count() != 0;
}
};
}
void SessionCount::purge() const
{
StopWatch sw;
m_cleanup_countdown = CleanupCountdown;
// erase entries up to the first non-zero one
auto ite = find_if(m_event_counts.begin(), m_event_counts.end(), NonZeroEntry());
// The gcc 4.4 vector::erase bug only happens if iterators are the same.
if (ite != m_event_counts.begin())
{
m_event_counts.erase(m_event_counts.begin(), ite);
}
}
void SessionCount::dump(std::ostream& os) const
{
purge();
if (!m_event_counts.empty())
{
os << " Session: " << m_sess_id << '\n';
for (auto ite = m_event_counts.begin(); ite != m_event_counts.end(); ++ite)
{
os << " " << *ite << '\n';
}
}
}
void dumpHeader(std::ostream& os, const SessionCount& stats, const std::string& type)
{
TimePoint tp = Clock::now();
os << type << ": Time:" << tp
<< " Time Window: " << stats.time_window() << '\n';
}
void dump(std::ostream& os, const std::vector<SessionCount>& sessions)
{
if (sessions.empty())
{
return;
}
dumpHeader(os, sessions[0], "Count");
for (auto session = sessions.begin(); session != sessions.end(); ++session)
{
session->dump(os);
}
}
void dumpTotals(std::ostream& os, const std::vector<SessionCount> &sessions)
{
if (sessions.empty())
{
return;
}
std::map<std::string, int> counts;
for (auto session = sessions.begin(); session != sessions.end(); ++session)
{
const auto& events = session->event_counts();
for (auto event = events.begin(); event != events.end(); ++event)
{
counts[event->event_id()] += event->count();
}
}
if (!counts.empty())
{
dumpHeader(os, sessions[0], "Count Totals");
for (auto ite = counts.begin(); ite != counts.end(); ++ite)
{
os << " " << ite->first << ": " << ite->second << '\n';
}
}
}
// EXTRA
// This section needed for gcc 4.4, to use move semantics and variadics.
EventCount::EventCount(EventCount && ss) :
m_event_id(std::move(ss.m_event_id)),
m_time_window(std::move(ss.m_time_window)),
m_granularity(std::move(ss.m_granularity)),
m_timestamps(std::move(ss.m_timestamps))
{
}
EventCount &EventCount::operator=(EventCount && ss)
{
m_event_id = std::move(ss.m_event_id);
m_time_window = std::move(ss.m_time_window);
m_granularity = std::move(ss.m_granularity);
m_timestamps = std::move(ss.m_timestamps);
return *this;
}
SessionCount::SessionCount(SessionCount&& ss) :
m_sess_id(std::move(ss.m_sess_id)),
m_time_window(std::move(ss.m_time_window)),
m_granularity(std::move(ss.m_granularity)),
m_cleanup_countdown(std::move(ss.m_cleanup_countdown)),
m_event_counts(std::move(ss.m_event_counts))
{
}
SessionCount & SessionCount::operator=(SessionCount&& ss)
{
m_sess_id = std::move(ss.m_sess_id);
m_time_window = std::move(ss.m_time_window);
m_granularity = std::move(ss.m_granularity);
m_cleanup_countdown = std::move(ss.m_cleanup_countdown);
m_event_counts = std::move(ss.m_event_counts);
return *this;
}
} // maxbase