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#pragma once
#include "flat_page_bloom.h"
#include "flat_bloom_hash.h"
#include "flat_util_binary.h"
#include "util_deref.h"
#include <library/cpp/actors/util/shared_data.h>
#include <util/generic/ymath.h>
#include <util/system/sanitizers.h>
namespace NKikimr {
namespace NTable {
namespace NBloom {
class IWriter {
public:
virtual ~IWriter() = default;
virtual void Reset() = 0;
virtual ui64 EstimateBytesUsed(size_t extraItems) const = 0;
virtual void Add(TArrayRef<const TCell> row) = 0;
virtual TSharedData Make() = 0;
};
class TEstimator {
public:
TEstimator(float error)
{
Y_ABORT_UNLESS(error > 0. && error < 1.,
"Invalid error estimation, should be in (0, 1)");
double log2err = Log2(error);
Amp = -1.44 * log2err;
Y_ABORT_UNLESS(Amp < 256., "Too high rows amplification factor");
HashCount = Min(ui64(Max<ui16>()), ui64(ceil(-log2err)));
}
ui64 Bits(ui64 rows) const noexcept
{
Y_ABORT_UNLESS(!(rows >> 54),
"Too many rows, probably an invalid value passed");
return ((Max(ui64(ceil(Amp * rows)), ui64(1)) + 63) >> 6) << 6;
}
ui16 Hashes() const noexcept
{
return HashCount;
}
private:
double Amp;
ui16 HashCount;
};
class TWriter final : public IWriter {
public:
TWriter(ui64 rows, float error)
{
TEstimator estimator(error);
Hashes = estimator.Hashes();
Items = estimator.Bits(rows);
Y_ABORT_UNLESS(Hashes && Items);
Reset();
}
void Reset() override
{
using THeader = NPage::TBloom::THeader;
ui64 array = (Items >> 6) * sizeof(ui64);
auto size = sizeof(NPage::TLabel) + sizeof(THeader) + array;
Raw = TSharedData::Uninitialized(size);
NUtil::NBin::TPut out(Raw.mutable_begin());
WriteUnaligned<NPage::TLabel>(out.Skip<NPage::TLabel>(),
NPage::TLabel::Encode(NPage::EPage::Bloom, 0, size));
if (auto *post = out.Skip<THeader>()) {
Zero(*post);
post->Type = 0;
post->Hashes = Hashes;
post->Items = Items;
}
Array = { TDeref<ui64>::At(*out, 0), size_t(Items >> 6) };
Y_ABORT_UNLESS(size_t(*out) % sizeof(ui64) == 0, "Invalid aligment");
Y_ABORT_UNLESS(TDeref<char>::At(Array.end(), 0) == Raw.mutable_end());
std::fill(Array.begin(), Array.end(), 0);
}
ui64 EstimateBytesUsed(size_t) const override
{
return Raw.size();
}
void Add(THashRoot root)
{
THash hash(root);
for (ui32 seq = 0; seq++ < Hashes; ) {
const ui64 num = hash.Next() % Items;
Array[num >> 6] |= ui64(1) << (num & 0x3f);
}
}
void Add(TArrayRef<const TCell> row) override
{
const TPrefix prefix(row);
Add(THash::Root(prefix.Get(row.size())));
}
TSharedData Make() override
{
NSan::CheckMemIsInitialized(Raw.data(), Raw.size());
return std::move(Raw);
}
private:
ui32 Hashes = 0;
ui64 Items = 0;
TSharedData Raw;
TArrayRef<ui64> Array;
};
class TQueue final : public IWriter {
public:
TQueue(float error)
: Estimator(error)
, Error(error)
{
}
void Reset() override
{
Roots.clear();
}
ui64 EstimateBytesUsed(size_t extraItems) const override
{
using THeader = NPage::TBloom::THeader;
ui64 array = (Estimator.Bits(Roots.size() + extraItems) >> 6) * sizeof(ui64);
return sizeof(NPage::TLabel) + sizeof(THeader) + array;
}
void Add(TArrayRef<const TCell> row) override
{
const TPrefix prefix(row);
Roots.push_back(THash::Root(prefix.Get(row.size())));
}
TSharedData Make() override
{
if (!Roots) {
return { };
}
TWriter writer(Roots.size(), Error);
for (const auto& root : Roots) {
writer.Add(root);
}
return writer.Make();
}
private:
TVector<THashRoot> Roots;
TEstimator Estimator;
float Error;
};
}
}
}
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