ClickHouse/src/Dictionaries/HashedDictionary.h
2023-02-06 10:50:58 +01:00

287 lines
11 KiB
C++

#pragma once
#include <atomic>
#include <memory>
#include <variant>
#include <optional>
#include <sparsehash/sparse_hash_map>
#include <sparsehash/sparse_hash_set>
#include <Common/HashTable/HashMap.h>
#include <Common/HashTable/HashSet.h>
#include <Core/Block.h>
#include <Dictionaries/DictionaryStructure.h>
#include <Dictionaries/IDictionary.h>
#include <Dictionaries/IDictionarySource.h>
#include <Dictionaries/DictionaryHelpers.h>
/** This dictionary stores all content in a hash table in memory
* (a separate Key -> Value map for each attribute)
* Two variants of hash table are supported: a fast HashMap and memory efficient sparse_hash_map.
*/
namespace DB
{
struct HashedDictionaryConfiguration
{
const UInt64 shards;
const UInt64 shard_load_queue_backlog;
const bool require_nonempty;
const DictionaryLifetime lifetime;
};
template <DictionaryKeyType dictionary_key_type, bool sparse, bool sharded>
class ParallelDictionaryLoader;
template <DictionaryKeyType dictionary_key_type, bool sparse, bool sharded>
class HashedDictionary final : public IDictionary
{
friend class ParallelDictionaryLoader<dictionary_key_type, sparse, sharded>;
public:
using KeyType = std::conditional_t<dictionary_key_type == DictionaryKeyType::Simple, UInt64, StringRef>;
HashedDictionary(
const StorageID & dict_id_,
const DictionaryStructure & dict_struct_,
DictionarySourcePtr source_ptr_,
const HashedDictionaryConfiguration & configuration_,
BlockPtr update_field_loaded_block_ = nullptr);
~HashedDictionary() override;
std::string getTypeName() const override
{
if constexpr (dictionary_key_type == DictionaryKeyType::Simple && sparse)
return "SparseHashed";
else if constexpr (dictionary_key_type == DictionaryKeyType::Simple && !sparse)
return "Hashed";
else if constexpr (dictionary_key_type == DictionaryKeyType::Complex && sparse)
return "ComplexKeySparseHashed";
else
return "ComplexKeyHashed";
}
size_t getBytesAllocated() const override { return bytes_allocated; }
size_t getQueryCount() const override { return query_count.load(std::memory_order_relaxed); }
double getFoundRate() const override
{
size_t queries = query_count.load(std::memory_order_relaxed);
if (!queries)
return 0;
return static_cast<double>(found_count.load(std::memory_order_relaxed)) / queries;
}
double getHitRate() const override { return 1.0; }
size_t getElementCount() const override { return element_count; }
double getLoadFactor() const override { return static_cast<double>(element_count) / bucket_count; }
std::shared_ptr<const IExternalLoadable> clone() const override
{
return std::make_shared<HashedDictionary<dictionary_key_type, sparse, sharded>>(
getDictionaryID(),
dict_struct,
source_ptr->clone(),
configuration,
update_field_loaded_block);
}
DictionarySourcePtr getSource() const override { return source_ptr; }
const DictionaryLifetime & getLifetime() const override { return configuration.lifetime; }
const DictionaryStructure & getStructure() const override { return dict_struct; }
bool isInjective(const std::string & attribute_name) const override
{
return dict_struct.getAttribute(attribute_name).injective;
}
DictionaryKeyType getKeyType() const override { return dictionary_key_type; }
ColumnPtr getColumn(
const std::string& attribute_name,
const DataTypePtr & result_type,
const Columns & key_columns,
const DataTypes & key_types,
const ColumnPtr & default_values_column) const override;
ColumnUInt8::Ptr hasKeys(const Columns & key_columns, const DataTypes & key_types) const override;
bool hasHierarchy() const override { return dictionary_key_type == DictionaryKeyType::Simple && dict_struct.hierarchical_attribute_index.has_value(); }
ColumnPtr getHierarchy(ColumnPtr key_column, const DataTypePtr & hierarchy_attribute_type) const override;
ColumnUInt8::Ptr isInHierarchy(
ColumnPtr key_column,
ColumnPtr in_key_column,
const DataTypePtr & key_type) const override;
DictionaryHierarchicalParentToChildIndexPtr getHierarchicalIndex() const override;
size_t getHierarchicalIndexBytesAllocated() const override { return hierarchical_index_bytes_allocated; }
ColumnPtr getDescendants(
ColumnPtr key_column,
const DataTypePtr & key_type,
size_t level,
DictionaryHierarchicalParentToChildIndexPtr parent_to_child_index) const override;
Pipe read(const Names & column_names, size_t max_block_size, size_t num_streams) const override;
private:
template <typename Value>
using CollectionTypeNonSparse = std::conditional_t<
dictionary_key_type == DictionaryKeyType::Simple,
HashMap<UInt64, Value, DefaultHash<UInt64>>,
HashMapWithSavedHash<StringRef, Value, DefaultHash<StringRef>>>;
using NoAttributesCollectionTypeNonSparse = std::conditional_t<
dictionary_key_type == DictionaryKeyType::Simple,
HashSet<UInt64, DefaultHash<UInt64>>,
HashSetWithSavedHash<StringRef, DefaultHash<StringRef>>>;
/// Here we use sparse_hash_map with DefaultHash<> for the following reasons:
///
/// - DefaultHash<> is used for HashMap
/// - DefaultHash<> (from HashTable/Hash.h> works better then std::hash<>
/// in case of sequential set of keys, but with random access to this set, i.e.
///
/// SELECT number FROM numbers(3000000) ORDER BY rand()
///
/// And even though std::hash<> works better in some other cases,
/// DefaultHash<> is preferred since the difference for this particular
/// case is significant, i.e. it can be 10x+.
template <typename Value>
using CollectionTypeSparse = std::conditional_t<
dictionary_key_type == DictionaryKeyType::Simple,
google::sparse_hash_map<UInt64, Value, DefaultHash<KeyType>>,
google::sparse_hash_map<StringRef, Value, DefaultHash<KeyType>>>;
using NoAttributesCollectionTypeSparse = google::sparse_hash_set<KeyType, DefaultHash<KeyType>>;
template <typename Value>
using CollectionType = std::conditional_t<sparse, CollectionTypeSparse<Value>, CollectionTypeNonSparse<Value>>;
template <typename Value>
using CollectionsHolder = std::vector<CollectionType<Value>>;
using NoAttributesCollectionType = std::conditional_t<sparse, NoAttributesCollectionTypeSparse, NoAttributesCollectionTypeNonSparse>;
using NullableSet = HashSet<KeyType, DefaultHash<KeyType>>;
using NullableSets = std::vector<NullableSet>;
struct Attribute final
{
AttributeUnderlyingType type;
std::optional<NullableSets> is_nullable_sets;
std::variant<
CollectionsHolder<UInt8>,
CollectionsHolder<UInt16>,
CollectionsHolder<UInt32>,
CollectionsHolder<UInt64>,
CollectionsHolder<UInt128>,
CollectionsHolder<UInt256>,
CollectionsHolder<Int8>,
CollectionsHolder<Int16>,
CollectionsHolder<Int32>,
CollectionsHolder<Int64>,
CollectionsHolder<Int128>,
CollectionsHolder<Int256>,
CollectionsHolder<Decimal32>,
CollectionsHolder<Decimal64>,
CollectionsHolder<Decimal128>,
CollectionsHolder<Decimal256>,
CollectionsHolder<DateTime64>,
CollectionsHolder<Float32>,
CollectionsHolder<Float64>,
CollectionsHolder<UUID>,
CollectionsHolder<IPv4>,
CollectionsHolder<IPv6>,
CollectionsHolder<StringRef>,
CollectionsHolder<Array>>
containers;
};
void createAttributes();
void blockToAttributes(const Block & block, DictionaryKeysArenaHolder<dictionary_key_type> & arena_holder, UInt64 shard);
void updateData();
void loadData();
void buildHierarchyParentToChildIndexIfNeeded();
void calculateBytesAllocated();
UInt64 getShard(UInt64 key) const
{
if constexpr (!sharded)
return 0;
/// NOTE: function here should not match with the DefaultHash<> since
/// it used for the HashMap/sparse_hash_map.
return intHashCRC32(key) % configuration.shards;
}
UInt64 getShard(StringRef key) const
{
if constexpr (!sharded)
return 0;
return StringRefHash()(key) % configuration.shards;
}
template <typename AttributeType, bool is_nullable, typename ValueSetter, typename DefaultValueExtractor>
void getItemsImpl(
const Attribute & attribute,
DictionaryKeysExtractor<dictionary_key_type> & keys_extractor,
ValueSetter && set_value,
DefaultValueExtractor & default_value_extractor) const;
template <typename GetContainersFunc>
void getAttributeContainers(size_t attribute_index, GetContainersFunc && get_containers_func);
template <typename GetContainersFunc>
void getAttributeContainers(size_t attribute_index, GetContainersFunc && get_containers_func) const;
void resize(size_t added_rows);
Poco::Logger * log;
const DictionaryStructure dict_struct;
const DictionarySourcePtr source_ptr;
const HashedDictionaryConfiguration configuration;
std::vector<Attribute> attributes;
size_t bytes_allocated = 0;
size_t hierarchical_index_bytes_allocated = 0;
std::atomic<size_t> element_count = 0;
size_t bucket_count = 0;
mutable std::atomic<size_t> query_count{0};
mutable std::atomic<size_t> found_count{0};
BlockPtr update_field_loaded_block;
std::vector<std::unique_ptr<Arena>> string_arenas;
std::vector<NoAttributesCollectionType> no_attributes_containers;
DictionaryHierarchicalParentToChildIndexPtr hierarchical_index;
};
extern template class HashedDictionary<DictionaryKeyType::Simple, false, /*sparse*/ false /*sharded*/>;
extern template class HashedDictionary<DictionaryKeyType::Simple, false /*sparse*/, true /*sharded*/>;
extern template class HashedDictionary<DictionaryKeyType::Simple, true /*sparse*/, false /*sharded*/>;
extern template class HashedDictionary<DictionaryKeyType::Simple, true /*sparse*/, true /*sharded*/>;
extern template class HashedDictionary<DictionaryKeyType::Complex, false /*sparse*/, false /*sharded*/>;
extern template class HashedDictionary<DictionaryKeyType::Complex, false /*sparse*/, true /*sharded*/>;
extern template class HashedDictionary<DictionaryKeyType::Complex, true /*sparse*/, false /*sharded*/>;
extern template class HashedDictionary<DictionaryKeyType::Complex, true /*sparse*/, true /*sharded*/>;
}