ClickHouse/src/Common/HashTable/TwoLevelHashMap.h
Nikita Taranov 100c055510
Prefetching in aggregation (#39304)
* impl

* stash

* clean up

* do not apply when HT is small

* make branch static

* also in merge

* do not hardcode look ahead value

* fix

* apply to methods with cheap key calculation

* more tests

* silence tidy

* fix build

* support HashMethodKeysFixed

* apply during merge only for cheap

* stash

* fixes

* rename method

* add feature flag

* cache prefetch threshold value

* fix

* fix

* Update HashMap.h

* fix typo

* 256KB as default l2 size

Co-authored-by: Alexey Milovidov <milovidov@clickhouse.com>
2022-09-21 18:59:07 +02:00

69 lines
2.0 KiB
C++

#pragma once
#include <Common/HashTable/TwoLevelHashTable.h>
#include <Common/HashTable/HashMap.h>
template
<
typename Key,
typename Cell,
typename Hash = DefaultHash<Key>,
typename Grower = TwoLevelHashTableGrower<>,
typename Allocator = HashTableAllocator,
template <typename ...> typename ImplTable = HashMapTable
>
class TwoLevelHashMapTable : public TwoLevelHashTable<Key, Cell, Hash, Grower, Allocator, ImplTable<Key, Cell, Hash, Grower, Allocator>>
{
public:
using Impl = ImplTable<Key, Cell, Hash, Grower, Allocator>;
using Base = TwoLevelHashTable<Key, Cell, Hash, Grower, Allocator, ImplTable<Key, Cell, Hash, Grower, Allocator>>;
using LookupResult = typename Impl::LookupResult;
using Base::Base;
using Base::prefetch;
template <typename Func>
void ALWAYS_INLINE forEachMapped(Func && func)
{
for (auto i = 0u; i < this->NUM_BUCKETS; ++i)
this->impls[i].forEachMapped(func);
}
typename Cell::Mapped & ALWAYS_INLINE operator[](const Key & x)
{
LookupResult it;
bool inserted;
this->emplace(x, it, inserted);
if (inserted)
new (&it->getMapped()) typename Cell::Mapped();
return it->getMapped();
}
};
template
<
typename Key,
typename Mapped,
typename Hash = DefaultHash<Key>,
typename Grower = TwoLevelHashTableGrower<>,
typename Allocator = HashTableAllocator,
template <typename ...> typename ImplTable = HashMapTable
>
using TwoLevelHashMap = TwoLevelHashMapTable<Key, HashMapCell<Key, Mapped, Hash>, Hash, Grower, Allocator, ImplTable>;
template
<
typename Key,
typename Mapped,
typename Hash = DefaultHash<Key>,
typename Grower = TwoLevelHashTableGrower<>,
typename Allocator = HashTableAllocator,
template <typename ...> typename ImplTable = HashMapTable
>
using TwoLevelHashMapWithSavedHash = TwoLevelHashMapTable<Key, HashMapCellWithSavedHash<Key, Mapped, Hash>, Hash, Grower, Allocator, ImplTable>;