ClickHouse/src/AggregateFunctions/ThetaSketchData.h
Alexey Milovidov 8b4a6a2416 Remove cruft
2021-10-28 02:10:39 +03:00

118 lines
2.9 KiB
C++

#pragma once
#include <Common/config.h>
#if USE_DATASKETCHES
#include <boost/noncopyable.hpp>
#include <memory>
#include <theta_sketch.hpp>
#include <theta_union.hpp>
namespace DB
{
template <typename Key>
class ThetaSketchData : private boost::noncopyable
{
private:
std::unique_ptr<datasketches::update_theta_sketch> sk_update;
std::unique_ptr<datasketches::theta_union> sk_union;
inline datasketches::update_theta_sketch * getSkUpdate()
{
if (!sk_update)
sk_update = std::make_unique<datasketches::update_theta_sketch>(datasketches::update_theta_sketch::builder().build());
return sk_update.get();
}
inline datasketches::theta_union * getSkUnion()
{
if (!sk_union)
sk_union = std::make_unique<datasketches::theta_union>(datasketches::theta_union::builder().build());
return sk_union.get();
}
public:
using value_type = Key;
ThetaSketchData() = default;
~ThetaSketchData() = default;
/// Insert original value without hash, as `datasketches::update_theta_sketch.update` will do the hash internal.
void insertOriginal(const StringRef & value)
{
getSkUpdate()->update(value.data, value.size);
}
/// Note that `datasketches::update_theta_sketch.update` will do the hash again.
void insert(Key value)
{
getSkUpdate()->update(value);
}
UInt64 size() const
{
if (sk_union)
return static_cast<UInt64>(sk_union->get_result().get_estimate());
else if (sk_update)
return static_cast<UInt64>(sk_update->get_estimate());
else
return 0;
}
void merge(const ThetaSketchData & rhs)
{
datasketches::theta_union * u = getSkUnion();
if (sk_update)
{
u->update(*sk_update);
sk_update.reset(nullptr);
}
if (rhs.sk_update)
u->update(*rhs.sk_update);
else if (rhs.sk_union)
u->update(rhs.sk_union->get_result());
}
/// You can only call for an empty object.
void read(DB::ReadBuffer & in)
{
datasketches::compact_theta_sketch::vector_bytes bytes;
readVectorBinary(bytes, in);
if (!bytes.empty())
{
auto sk = datasketches::compact_theta_sketch::deserialize(bytes.data(), bytes.size());
getSkUnion()->update(sk);
}
}
void write(DB::WriteBuffer & out) const
{
if (sk_update)
{
auto bytes = sk_update->compact().serialize();
writeVectorBinary(bytes, out);
}
else if (sk_union)
{
auto bytes = sk_union->get_result().serialize();
writeVectorBinary(bytes, out);
}
else
{
datasketches::compact_theta_sketch::vector_bytes bytes;
writeVectorBinary(bytes, out);
}
}
};
}
#endif