ClickHouse/src/AggregateFunctions/AggregateFunctionWindowFunnel.h

303 lines
9.8 KiB
C++

#pragma once
#include <unordered_set>
#include <Columns/ColumnsNumber.h>
#include <DataTypes/DataTypeDateTime.h>
#include <DataTypes/DataTypesNumber.h>
#include <IO/ReadHelpers.h>
#include <IO/WriteHelpers.h>
#include <Common/ArenaAllocator.h>
#include <Common/assert_cast.h>
#include <AggregateFunctions/AggregateFunctionNull.h>
namespace DB
{
struct Settings;
namespace ErrorCodes
{
extern const int BAD_ARGUMENTS;
}
static constexpr auto max_events = 32;
template <typename T>
struct AggregateFunctionWindowFunnelData
{
using TimestampEvent = std::pair<T, UInt8>;
using TimestampEvents = PODArrayWithStackMemory<TimestampEvent, 64>;
bool sorted = true;
TimestampEvents events_list;
size_t size() const
{
return events_list.size();
}
void add(T timestamp, UInt8 event)
{
/// Since most events should have already been sorted by timestamp.
if (sorted && events_list.size() > 0)
{
if (events_list.back().first == timestamp)
sorted = events_list.back().second <= event;
else
sorted = events_list.back().first <= timestamp;
}
events_list.emplace_back(timestamp, event);
}
void merge(const AggregateFunctionWindowFunnelData & other)
{
if (other.events_list.empty())
return;
const auto size = events_list.size();
events_list.insert(std::begin(other.events_list), std::end(other.events_list));
/// either sort whole container or do so partially merging ranges afterwards
if (!sorted && !other.sorted)
std::stable_sort(std::begin(events_list), std::end(events_list));
else
{
const auto begin = std::begin(events_list);
const auto middle = std::next(begin, size);
const auto end = std::end(events_list);
if (!sorted)
std::stable_sort(begin, middle);
if (!other.sorted)
std::stable_sort(middle, end);
std::inplace_merge(begin, middle, end);
}
sorted = true;
}
void sort()
{
if (!sorted)
{
std::stable_sort(std::begin(events_list), std::end(events_list));
sorted = true;
}
}
void serialize(WriteBuffer & buf) const
{
writeBinary(sorted, buf);
writeBinary(events_list.size(), buf);
for (const auto & events : events_list)
{
writeBinary(events.first, buf);
writeBinary(events.second, buf);
}
}
void deserialize(ReadBuffer & buf)
{
readBinary(sorted, buf);
size_t size;
readBinary(size, buf);
/// TODO Protection against huge size
events_list.clear();
events_list.reserve(size);
T timestamp;
UInt8 event;
for (size_t i = 0; i < size; ++i)
{
readBinary(timestamp, buf);
readBinary(event, buf);
events_list.emplace_back(timestamp, event);
}
}
};
/** Calculates the max event level in a sliding window.
* The max size of events is 32, that's enough for funnel analytics
*
* Usage:
* - windowFunnel(window)(timestamp, cond1, cond2, cond3, ....)
*/
template <typename T, typename Data>
class AggregateFunctionWindowFunnel final
: public IAggregateFunctionDataHelper<Data, AggregateFunctionWindowFunnel<T, Data>>
{
private:
UInt64 window;
UInt8 events_size;
/// When the 'strict_deduplication' is set, it applies conditions only for the not repeating values.
bool strict_deduplication;
/// When the 'strict_order' is set, it doesn't allow interventions of other events.
/// In the case of 'A->B->D->C', it stops finding 'A->B->C' at the 'D' and the max event level is 2.
bool strict_order;
/// Applies conditions only to events with strictly increasing timestamps
bool strict_increase;
/// Loop through the entire events_list, update the event timestamp value
/// The level path must be 1---2---3---...---check_events_size, find the max event level that satisfied the path in the sliding window.
/// If found, returns the max event level, else return 0.
/// The algorithm works in O(n) time, but the overall function works in O(n * log(n)) due to sorting.
UInt8 getEventLevel(Data & data) const
{
if (data.size() == 0)
return 0;
if (!strict_order && events_size == 1)
return 1;
data.sort();
/// events_timestamp stores the timestamp of the first and previous i-th level event happen within time window
std::vector<std::optional<std::pair<UInt64, UInt64>>> events_timestamp(events_size);
bool first_event = false;
for (size_t i = 0; i < data.events_list.size(); ++i)
{
const T & timestamp = data.events_list[i].first;
const auto & event_idx = data.events_list[i].second - 1;
if (strict_order && event_idx == -1)
{
if (first_event)
break;
else
continue;
}
else if (event_idx == 0)
{
events_timestamp[0] = std::make_pair(timestamp, timestamp);
first_event = true;
}
else if (strict_deduplication && events_timestamp[event_idx].has_value())
{
return data.events_list[i - 1].second;
}
else if (strict_order && first_event && !events_timestamp[event_idx - 1].has_value())
{
for (size_t event = 0; event < events_timestamp.size(); ++event)
{
if (!events_timestamp[event].has_value())
return event;
}
}
else if (events_timestamp[event_idx - 1].has_value())
{
auto first_timestamp = events_timestamp[event_idx - 1]->first;
bool time_matched = timestamp <= first_timestamp + window;
if (strict_increase)
time_matched = time_matched && events_timestamp[event_idx - 1]->second < timestamp;
if (time_matched)
{
events_timestamp[event_idx] = std::make_pair(first_timestamp, timestamp);
if (event_idx + 1 == events_size)
return events_size;
}
}
}
for (size_t event = events_timestamp.size(); event > 0; --event)
{
if (events_timestamp[event - 1].has_value())
return event;
}
return 0;
}
public:
String getName() const override
{
return "windowFunnel";
}
AggregateFunctionWindowFunnel(const DataTypes & arguments, const Array & params)
: IAggregateFunctionDataHelper<Data, AggregateFunctionWindowFunnel<T, Data>>(arguments, params)
{
events_size = arguments.size() - 1;
window = params.at(0).safeGet<UInt64>();
strict_deduplication = false;
strict_order = false;
strict_increase = false;
for (size_t i = 1; i < params.size(); ++i)
{
String option = params.at(i).safeGet<String>();
if (option == "strict_deduplication")
strict_deduplication = true;
else if (option == "strict_order")
strict_order = true;
else if (option == "strict_increase")
strict_increase = true;
else if (option == "strict")
throw Exception{"strict is replaced with strict_deduplication in Aggregate function " + getName(), ErrorCodes::BAD_ARGUMENTS};
else
throw Exception{"Aggregate function " + getName() + " doesn't support a parameter: " + option, ErrorCodes::BAD_ARGUMENTS};
}
}
DataTypePtr getReturnType() const override
{
return std::make_shared<DataTypeUInt8>();
}
bool allocatesMemoryInArena() const override { return false; }
AggregateFunctionPtr getOwnNullAdapter(
const AggregateFunctionPtr & nested_function, const DataTypes & arguments, const Array & params,
const AggregateFunctionProperties & /*properties*/) const override
{
return std::make_shared<AggregateFunctionNullVariadic<false, false, false>>(nested_function, arguments, params);
}
void add(AggregateDataPtr __restrict place, const IColumn ** columns, const size_t row_num, Arena *) const override
{
bool has_event = false;
const auto timestamp = assert_cast<const ColumnVector<T> *>(columns[0])->getData()[row_num];
/// reverse iteration and stable sorting are needed for events that are qualified by more than one condition.
for (auto i = events_size; i > 0; --i)
{
auto event = assert_cast<const ColumnVector<UInt8> *>(columns[i])->getData()[row_num];
if (event)
{
this->data(place).add(timestamp, i);
has_event = true;
}
}
if (strict_order && !has_event)
this->data(place).add(timestamp, 0);
}
void merge(AggregateDataPtr __restrict place, ConstAggregateDataPtr rhs, Arena *) const override
{
this->data(place).merge(this->data(rhs));
}
void serialize(ConstAggregateDataPtr __restrict place, WriteBuffer & buf, std::optional<size_t> /* version */) const override
{
this->data(place).serialize(buf);
}
void deserialize(AggregateDataPtr __restrict place, ReadBuffer & buf, std::optional<size_t> /* version */, Arena *) const override
{
this->data(place).deserialize(buf);
}
void insertResultInto(AggregateDataPtr __restrict place, IColumn & to, Arena *) const override
{
assert_cast<ColumnUInt8 &>(to).getData().push_back(getEventLevel(this->data(place)));
}
};
}