ClickHouse/dbms/include/DB/Dictionaries/CacheDictionary.h
2015-10-05 03:33:43 +03:00

631 lines
21 KiB
C++

#pragma once
#include <DB/Dictionaries/IDictionary.h>
#include <DB/Dictionaries/IDictionarySource.h>
#include <DB/Dictionaries/DictionaryStructure.h>
#include <DB/Common/HashTable/HashMap.h>
#include <DB/Columns/ColumnString.h>
#include <DB/Common/HashTable/HashMap.h>
#include <ext/scope_guard.hpp>
#include <Poco/RWLock.h>
#include <cmath>
#include <atomic>
#include <chrono>
#include <vector>
#include <map>
#include <tuple>
namespace DB
{
class CacheDictionary final : public IDictionary
{
public:
CacheDictionary(const std::string & name, const DictionaryStructure & dict_struct,
DictionarySourcePtr source_ptr, const DictionaryLifetime dict_lifetime,
const std::size_t size)
: name{name}, dict_struct(dict_struct),
source_ptr{std::move(source_ptr)}, dict_lifetime(dict_lifetime),
size{round_up_to_power_of_two(size)},
cells{this->size}
{
if (!this->source_ptr->supportsSelectiveLoad())
throw Exception{
name + ": source cannot be used with CacheDictionary",
ErrorCodes::UNSUPPORTED_METHOD
};
createAttributes();
}
CacheDictionary(const CacheDictionary & other)
: CacheDictionary{other.name, other.dict_struct, other.source_ptr->clone(), other.dict_lifetime, other.size}
{}
std::exception_ptr getCreationException() const override { return {}; }
std::string getName() const override { return name; }
std::string getTypeName() const override { return "Cache"; }
std::size_t getBytesAllocated() const override { return bytes_allocated; }
std::size_t getQueryCount() const override { return query_count.load(std::memory_order_relaxed); }
double getHitRate() const override
{
return static_cast<double>(hit_count.load(std::memory_order_acquire)) /
query_count.load(std::memory_order_relaxed);
}
std::size_t getElementCount() const override { return element_count.load(std::memory_order_relaxed); }
double getLoadFactor() const override
{
return static_cast<double>(element_count.load(std::memory_order_relaxed)) / size;
}
bool isCached() const override { return true; }
DictionaryPtr clone() const override { return std::make_unique<CacheDictionary>(*this); }
const IDictionarySource * getSource() const override { return source_ptr.get(); }
const DictionaryLifetime & getLifetime() const override { return dict_lifetime; }
const DictionaryStructure & getStructure() const override { return dict_struct; }
std::chrono::time_point<std::chrono::system_clock> getCreationTime() const override
{
return creation_time;
}
bool isInjective(const std::string & attribute_name) const override
{
return dict_struct.attributes[&getAttribute(attribute_name) - attributes.data()].injective;
}
bool hasHierarchy() const override { return hierarchical_attribute; }
void toParent(const PODArray<id_t> & ids, PODArray<id_t> & out) const override
{
getItems<UInt64>(*hierarchical_attribute, ids, out);
}
#define DECLARE_MULTIPLE_GETTER(TYPE)\
void get##TYPE(const std::string & attribute_name, const PODArray<id_t> & ids, PODArray<TYPE> & out) const override\
{\
auto & attribute = getAttribute(attribute_name);\
if (attribute.type != AttributeUnderlyingType::TYPE)\
throw Exception{\
name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type),\
ErrorCodes::TYPE_MISMATCH\
};\
\
getItems<TYPE>(attribute, ids, out);\
}
DECLARE_MULTIPLE_GETTER(UInt8)
DECLARE_MULTIPLE_GETTER(UInt16)
DECLARE_MULTIPLE_GETTER(UInt32)
DECLARE_MULTIPLE_GETTER(UInt64)
DECLARE_MULTIPLE_GETTER(Int8)
DECLARE_MULTIPLE_GETTER(Int16)
DECLARE_MULTIPLE_GETTER(Int32)
DECLARE_MULTIPLE_GETTER(Int64)
DECLARE_MULTIPLE_GETTER(Float32)
DECLARE_MULTIPLE_GETTER(Float64)
#undef DECLARE_MULTIPLE_GETTER
void getString(const std::string & attribute_name, const PODArray<id_t> & ids, ColumnString * out) const override
{
auto & attribute = getAttribute(attribute_name);
if (attribute.type != AttributeUnderlyingType::String)
throw Exception{
name + ": type mismatch: attribute " + attribute_name + " has type " + toString(attribute.type),
ErrorCodes::TYPE_MISMATCH
};
getItems(attribute, ids, out);
}
private:
struct cell_metadata_t final
{
std::uint64_t id;
std::chrono::system_clock::time_point expires_at;
};
struct attribute_t final
{
AttributeUnderlyingType type;
std::tuple<UInt8, UInt16, UInt32, UInt64,
Int8, Int16, Int32, Int64,
Float32, Float64,
String> null_values;
std::tuple<std::unique_ptr<UInt8[]>,
std::unique_ptr<UInt16[]>,
std::unique_ptr<UInt32[]>,
std::unique_ptr<UInt64[]>,
std::unique_ptr<Int8[]>,
std::unique_ptr<Int16[]>,
std::unique_ptr<Int32[]>,
std::unique_ptr<Int64[]>,
std::unique_ptr<Float32[]>,
std::unique_ptr<Float64[]>,
std::unique_ptr<StringRef[]>> arrays;
};
void createAttributes()
{
const auto size = dict_struct.attributes.size();
attributes.reserve(size);
bytes_allocated += size * sizeof(cell_metadata_t);
bytes_allocated += size * sizeof(attributes.front());
for (const auto & attribute : dict_struct.attributes)
{
attribute_index_by_name.emplace(attribute.name, attributes.size());
attributes.push_back(createAttributeWithType(attribute.underlying_type, attribute.null_value));
if (attribute.hierarchical)
{
hierarchical_attribute = &attributes.back();
if (hierarchical_attribute->type != AttributeUnderlyingType::UInt64)
throw Exception{
name + ": hierarchical attribute must be UInt64.",
ErrorCodes::TYPE_MISMATCH
};
}
}
}
attribute_t createAttributeWithType(const AttributeUnderlyingType type, const Field & null_value)
{
attribute_t attr{type};
switch (type)
{
case AttributeUnderlyingType::UInt8:
std::get<UInt8>(attr.null_values) = null_value.get<UInt64>();
std::get<std::unique_ptr<UInt8[]>>(attr.arrays) = std::make_unique<UInt8[]>(size);
bytes_allocated += size * sizeof(UInt8);
break;
case AttributeUnderlyingType::UInt16:
std::get<UInt16>(attr.null_values) = null_value.get<UInt64>();
std::get<std::unique_ptr<UInt16[]>>(attr.arrays) = std::make_unique<UInt16[]>(size);
bytes_allocated += size * sizeof(UInt16);
break;
case AttributeUnderlyingType::UInt32:
std::get<UInt32>(attr.null_values) = null_value.get<UInt64>();
std::get<std::unique_ptr<UInt32[]>>(attr.arrays) = std::make_unique<UInt32[]>(size);
bytes_allocated += size * sizeof(UInt32);
break;
case AttributeUnderlyingType::UInt64:
std::get<UInt64>(attr.null_values) = null_value.get<UInt64>();
std::get<std::unique_ptr<UInt64[]>>(attr.arrays) = std::make_unique<UInt64[]>(size);
bytes_allocated += size * sizeof(UInt64);
break;
case AttributeUnderlyingType::Int8:
std::get<Int8>(attr.null_values) = null_value.get<Int64>();
std::get<std::unique_ptr<Int8[]>>(attr.arrays) = std::make_unique<Int8[]>(size);
bytes_allocated += size * sizeof(Int8);
break;
case AttributeUnderlyingType::Int16:
std::get<Int16>(attr.null_values) = null_value.get<Int64>();
std::get<std::unique_ptr<Int16[]>>(attr.arrays) = std::make_unique<Int16[]>(size);
bytes_allocated += size * sizeof(Int16);
break;
case AttributeUnderlyingType::Int32:
std::get<Int32>(attr.null_values) = null_value.get<Int64>();
std::get<std::unique_ptr<Int32[]>>(attr.arrays) = std::make_unique<Int32[]>(size);
bytes_allocated += size * sizeof(Int32);
break;
case AttributeUnderlyingType::Int64:
std::get<Int64>(attr.null_values) = null_value.get<Int64>();
std::get<std::unique_ptr<Int64[]>>(attr.arrays) = std::make_unique<Int64[]>(size);
bytes_allocated += size * sizeof(Int64);
break;
case AttributeUnderlyingType::Float32:
std::get<Float32>(attr.null_values) = null_value.get<Float64>();
std::get<std::unique_ptr<Float32[]>>(attr.arrays) = std::make_unique<Float32[]>(size);
bytes_allocated += size * sizeof(Float32);
break;
case AttributeUnderlyingType::Float64:
std::get<Float64>(attr.null_values) = null_value.get<Float64>();
std::get<std::unique_ptr<Float64[]>>(attr.arrays) = std::make_unique<Float64[]>(size);
bytes_allocated += size * sizeof(Float64);
break;
case AttributeUnderlyingType::String:
std::get<String>(attr.null_values) = null_value.get<String>();
std::get<std::unique_ptr<StringRef[]>>(attr.arrays) = std::make_unique<StringRef[]>(size);
bytes_allocated += size * sizeof(StringRef);
break;
}
return attr;
}
template <typename T>
void getItems(attribute_t & attribute, const PODArray<id_t> & ids, PODArray<T> & out) const
{
HashMap<id_t, std::vector<std::size_t>> outdated_ids;
auto & attribute_array = std::get<std::unique_ptr<T[]>>(attribute.arrays);
{
const Poco::ScopedReadRWLock read_lock{rw_lock};
const auto now = std::chrono::system_clock::now();
/// fetch up-to-date values, decide which ones require update
for (const auto i : ext::range(0, ids.size()))
{
const auto id = ids[i];
if (id == 0)
{
out[i] = std::get<T>(attribute.null_values);
continue;
}
const auto cell_idx = getCellIdx(id);
const auto & cell = cells[cell_idx];
if (cell.id != id || cell.expires_at < now)
{
out[i] = std::get<T>(attribute.null_values);
outdated_ids[id].push_back(i);
}
else
out[i] = attribute_array[cell_idx];
}
}
query_count.fetch_add(ids.size(), std::memory_order_relaxed);
hit_count.fetch_add(ids.size() - outdated_ids.size(), std::memory_order_release);
if (outdated_ids.empty())
return;
/// request new values
std::vector<id_t> required_ids(outdated_ids.size());
std::transform(std::begin(outdated_ids), std::end(outdated_ids), std::begin(required_ids),
[] (auto & pair) { return pair.first; });
update(required_ids, [&] (const auto id, const auto cell_idx) {
const auto attribute_value = attribute_array[cell_idx];
/// set missing values to out
for (const auto out_idx : outdated_ids[id])
out[out_idx] = attribute_value;
});
}
void getItems(attribute_t & attribute, const PODArray<id_t> & ids, ColumnString * out) const
{
/// save on some allocations
out->getOffsets().reserve(ids.size());
auto & attribute_array = std::get<std::unique_ptr<StringRef[]>>(attribute.arrays);
auto found_outdated_values = false;
/// perform optimistic version, fallback to pessimistic if failed
{
const Poco::ScopedReadRWLock read_lock{rw_lock};
const auto now = std::chrono::system_clock::now();
/// fetch up-to-date values, discard on fail
for (const auto i : ext::range(0, ids.size()))
{
const auto id = ids[i];
const auto cell_idx = getCellIdx(id);
const auto & cell = cells[cell_idx];
if (cell.id != id || cell.expires_at < now)
{
found_outdated_values = true;
break;
}
else
{
const auto string_ref = attribute_array[cell_idx];
out->insertData(string_ref.data, string_ref.size);
}
}
}
/// optimistic code completed successfully
if (!found_outdated_values)
{
query_count.fetch_add(ids.size(), std::memory_order_relaxed);
hit_count.fetch_add(ids.size(), std::memory_order_release);
return;
}
/// now onto the pessimistic one, discard possibly partial results from the optimistic path
out->getChars().resize_assume_reserved(0);
out->getOffsets().resize_assume_reserved(0);
/// outdated ids joined number of times they've been requested
HashMap<id_t, std::size_t> outdated_ids;
/// we are going to store every string separately
HashMap<id_t, String> map;
std::size_t total_length = 0;
{
const Poco::ScopedReadRWLock read_lock{rw_lock};
const auto now = std::chrono::system_clock::now();
for (const auto i : ext::range(0, ids.size()))
{
const auto id = ids[i];
const auto cell_idx = getCellIdx(id);
const auto & cell = cells[cell_idx];
if (cell.id != id || cell.expires_at < now)
outdated_ids[id] += 1;
else
{
const auto string_ref = attribute_array[cell_idx];
map[id] = String{string_ref};
total_length += string_ref.size + 1;
}
}
}
query_count.fetch_add(ids.size(), std::memory_order_relaxed);
hit_count.fetch_add(ids.size() - outdated_ids.size(), std::memory_order_release);
/// request new values
if (!outdated_ids.empty())
{
std::vector<id_t> required_ids(outdated_ids.size());
std::transform(std::begin(outdated_ids), std::end(outdated_ids), std::begin(required_ids),
[] (auto & pair) { return pair.first; });
update(required_ids, [&] (const auto id, const auto cell_idx) {
const auto attribute_value = attribute_array[cell_idx];
map[id] = String{attribute_value};
total_length += (attribute_value.size + 1) * outdated_ids[id];
});
}
out->getChars().reserve(total_length);
for (const auto id : ids)
{
const auto it = map.find(id);
const auto string = it != map.end() ? it->second : std::get<String>(attribute.null_values);
out->insertData(string.data(), string.size());
}
}
template <typename F>
void update(const std::vector<id_t> ids, F && on_cell_updated) const
{
auto stream = source_ptr->loadIds(ids);
stream->readPrefix();
HashMap<UInt64, UInt8> remaining_ids{ids.size()};
for (const auto id : ids)
remaining_ids.insert({ id, 0 });
std::uniform_int_distribution<std::uint64_t> distribution{
dict_lifetime.min_sec,
dict_lifetime.max_sec
};
const Poco::ScopedWriteRWLock write_lock{rw_lock};
while (const auto block = stream->read())
{
const auto id_column = typeid_cast<const ColumnVector<UInt64> *>(block.getByPosition(0).column.get());
if (!id_column)
throw Exception{
name + ": id column has type different from UInt64.",
ErrorCodes::TYPE_MISMATCH
};
const auto & ids = id_column->getData();
/// cache column pointers
std::vector<const IColumn *> column_ptrs(attributes.size());
for (const auto i : ext::range(0, attributes.size()))
column_ptrs[i] = block.getByPosition(i + 1).column.get();
for (const auto i : ext::range(0, ids.size()))
{
const auto id = ids[i];
const auto cell_idx = getCellIdx(id);
auto & cell = cells[cell_idx];
for (const auto attribute_idx : ext::range(0, attributes.size()))
{
const auto & attribute_column = *column_ptrs[attribute_idx];
auto & attribute = attributes[attribute_idx];
setAttributeValue(attribute, cell_idx, attribute_column[i]);
}
/// if cell id is zero and zero does not map to this cell, then the cell is unused
if (cell.id == 0 && cell_idx != zero_cell_idx)
element_count.fetch_add(1, std::memory_order_relaxed);
cell.id = id;
if (dict_lifetime.min_sec != 0 && dict_lifetime.max_sec != 0)
cell.expires_at = std::chrono::system_clock::now() + std::chrono::seconds{distribution(rnd_engine)};
else
cell.expires_at = std::chrono::time_point<std::chrono::system_clock>::max();
on_cell_updated(id, cell_idx);
remaining_ids[id] = 1;
}
}
stream->readSuffix();
for (const auto id_found_pair : remaining_ids)
{
if (id_found_pair.second)
continue;
const auto id = id_found_pair.first;
const auto cell_idx = getCellIdx(id);
auto & cell = cells[cell_idx];
for (auto & attribute : attributes)
setDefaultAttributeValue(attribute, cell_idx);
if (cell.id == 0 && cell_idx != zero_cell_idx)
element_count.fetch_add(1, std::memory_order_relaxed);
cell.id = id;
if (dict_lifetime.min_sec != 0 && dict_lifetime.max_sec != 0)
cell.expires_at = std::chrono::system_clock::now() + std::chrono::seconds{distribution(rnd_engine)};
else
cell.expires_at = std::chrono::time_point<std::chrono::system_clock>::max();
on_cell_updated(id, cell_idx);
}
}
std::uint64_t getCellIdx(const id_t id) const
{
const auto hash = intHash64(id);
const auto idx = hash & (size - 1);
return idx;
}
void setDefaultAttributeValue(attribute_t & attribute, const id_t idx) const
{
switch (attribute.type)
{
case AttributeUnderlyingType::UInt8: std::get<std::unique_ptr<UInt8[]>>(attribute.arrays)[idx] = std::get<UInt8>(attribute.null_values); break;
case AttributeUnderlyingType::UInt16: std::get<std::unique_ptr<UInt16[]>>(attribute.arrays)[idx] = std::get<UInt16>(attribute.null_values); break;
case AttributeUnderlyingType::UInt32: std::get<std::unique_ptr<UInt32[]>>(attribute.arrays)[idx] = std::get<UInt32>(attribute.null_values); break;
case AttributeUnderlyingType::UInt64: std::get<std::unique_ptr<UInt64[]>>(attribute.arrays)[idx] = std::get<UInt64>(attribute.null_values); break;
case AttributeUnderlyingType::Int8: std::get<std::unique_ptr<Int8[]>>(attribute.arrays)[idx] = std::get<Int8>(attribute.null_values); break;
case AttributeUnderlyingType::Int16: std::get<std::unique_ptr<Int16[]>>(attribute.arrays)[idx] = std::get<Int16>(attribute.null_values); break;
case AttributeUnderlyingType::Int32: std::get<std::unique_ptr<Int32[]>>(attribute.arrays)[idx] = std::get<Int32>(attribute.null_values); break;
case AttributeUnderlyingType::Int64: std::get<std::unique_ptr<Int64[]>>(attribute.arrays)[idx] = std::get<Int64>(attribute.null_values); break;
case AttributeUnderlyingType::Float32: std::get<std::unique_ptr<Float32[]>>(attribute.arrays)[idx] = std::get<Float32>(attribute.null_values); break;
case AttributeUnderlyingType::Float64: std::get<std::unique_ptr<Float64[]>>(attribute.arrays)[idx] = std::get<Float64>(attribute.null_values); break;
case AttributeUnderlyingType::String:
{
const auto & null_value_ref = std::get<String>(attribute.null_values);
auto & string_ref = std::get<std::unique_ptr<StringRef[]>>(attribute.arrays)[idx];
if (string_ref.data == null_value_ref.data())
return;
if (string_ref.size != 0)
bytes_allocated -= string_ref.size + 1;
const std::unique_ptr<const char[]> deleter{string_ref.data};
string_ref = StringRef{null_value_ref};
break;
}
}
}
void setAttributeValue(attribute_t & attribute, const id_t idx, const Field & value) const
{
switch (attribute.type)
{
case AttributeUnderlyingType::UInt8: std::get<std::unique_ptr<UInt8[]>>(attribute.arrays)[idx] = value.get<UInt64>(); break;
case AttributeUnderlyingType::UInt16: std::get<std::unique_ptr<UInt16[]>>(attribute.arrays)[idx] = value.get<UInt64>(); break;
case AttributeUnderlyingType::UInt32: std::get<std::unique_ptr<UInt32[]>>(attribute.arrays)[idx] = value.get<UInt64>(); break;
case AttributeUnderlyingType::UInt64: std::get<std::unique_ptr<UInt64[]>>(attribute.arrays)[idx] = value.get<UInt64>(); break;
case AttributeUnderlyingType::Int8: std::get<std::unique_ptr<Int8[]>>(attribute.arrays)[idx] = value.get<Int64>(); break;
case AttributeUnderlyingType::Int16: std::get<std::unique_ptr<Int16[]>>(attribute.arrays)[idx] = value.get<Int64>(); break;
case AttributeUnderlyingType::Int32: std::get<std::unique_ptr<Int32[]>>(attribute.arrays)[idx] = value.get<Int64>(); break;
case AttributeUnderlyingType::Int64: std::get<std::unique_ptr<Int64[]>>(attribute.arrays)[idx] = value.get<Int64>(); break;
case AttributeUnderlyingType::Float32: std::get<std::unique_ptr<Float32[]>>(attribute.arrays)[idx] = value.get<Float64>(); break;
case AttributeUnderlyingType::Float64: std::get<std::unique_ptr<Float64[]>>(attribute.arrays)[idx] = value.get<Float64>(); break;
case AttributeUnderlyingType::String:
{
const auto & string = value.get<String>();
auto & string_ref = std::get<std::unique_ptr<StringRef[]>>(attribute.arrays)[idx];
const auto & null_value_ref = std::get<String>(attribute.null_values);
if (string_ref.data != null_value_ref.data())
{
if (string_ref.size != 0)
bytes_allocated -= string_ref.size + 1;
/// avoid explicit delete, let unique_ptr handle it
const std::unique_ptr<const char[]> deleter{string_ref.data};
}
const auto size = string.size();
if (size != 0)
{
auto string_ptr = std::make_unique<char[]>(size + 1);
std::copy(string.data(), string.data() + size + 1, string_ptr.get());
string_ref = StringRef{string_ptr.release(), size};
bytes_allocated += size + 1;
}
else
string_ref = {};
break;
}
}
}
attribute_t & getAttribute(const std::string & attribute_name) const
{
const auto it = attribute_index_by_name.find(attribute_name);
if (it == std::end(attribute_index_by_name))
throw Exception{
name + ": no such attribute '" + attribute_name + "'",
ErrorCodes::BAD_ARGUMENTS
};
return attributes[it->second];
}
static std::size_t round_up_to_power_of_two(std::size_t n)
{
--n;
n |= n >> 1;
n |= n >> 2;
n |= n >> 4;
n |= n >> 8;
n |= n >> 16;
n |= n >> 32;
++n;
return n;
}
static std::uint64_t getSeed()
{
timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return ts.tv_nsec ^ getpid();
}
const std::string name;
const DictionaryStructure dict_struct;
const DictionarySourcePtr source_ptr;
const DictionaryLifetime dict_lifetime;
mutable Poco::RWLock rw_lock;
const std::size_t size;
const std::uint64_t zero_cell_idx{getCellIdx(0)};
std::map<std::string, std::size_t> attribute_index_by_name;
mutable std::vector<attribute_t> attributes;
mutable std::vector<cell_metadata_t> cells;
attribute_t * hierarchical_attribute = nullptr;
mutable std::mt19937_64 rnd_engine{getSeed()};
mutable std::size_t bytes_allocated = 0;
mutable std::atomic<std::size_t> element_count{0};
mutable std::atomic<std::size_t> hit_count{0};
mutable std::atomic<std::size_t> query_count{0};
const std::chrono::time_point<std::chrono::system_clock> creation_time = std::chrono::system_clock::now();
};
}