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dbms: more scalable aggregator: development [#METR-2944].

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This commit is contained in:
Alexey Milovidov 2014-12-27 09:29:20 +03:00
parent 5b6ce478cf
commit ef160102f6
2 changed files with 12 additions and 38 deletions
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14
dbms/include/DB/Common/HashTable/TwoLevelHashTable.h
View File

@ -4,7 +4,7 @@
/** Двухуровневая хэш-таблица.
* Представляет собой 256 маленьких хэш-таблиц (bucket-ов первого уровня).
* Представляет собой 256 (или 1 << BITS_FOR_BUCKET) маленьких хэш-таблиц (bucket-ов первого уровня).
* Для определения, какую из них использовать, берётся один из байтов хэш-функции.
*
* Обычно работает чуть-чуть медленнее простой хэш-таблицы.
@ -31,7 +31,8 @@ template
typename Hash,
typename Grower,
typename Allocator, /// TODO WithStackMemory
typename ImplTable = HashTable<Key, Cell, Hash, Grower, Allocator>
typename ImplTable = HashTable<Key, Cell, Hash, Grower, Allocator>,
size_t BITS_FOR_BUCKET = 8
>
class TwoLevelHashTable :
private boost::noncopyable,
@ -46,8 +47,13 @@ protected:
public:
typedef ImplTable Impl;
static constexpr size_t NUM_BUCKETS = 1 << BITS_FOR_BUCKET;
static constexpr size_t MAX_BUCKET = NUM_BUCKETS - 1;
size_t hash(const Key & x) const { return Hash::operator()(x); }
size_t getBucketFromHash(size_t hash_value) const { return (hash_value >> 24) & 0xFF; } /// NOTE Плохо для хэш-таблиц больше чем на 2^32 ячеек.
/// NOTE Плохо для хэш-таблиц больше чем на 2^32 ячеек.
size_t getBucketFromHash(size_t hash_value) const { return (hash_value >> (32 - BITS_FOR_BUCKET)) & MAX_BUCKET; }
protected:
typename Impl::iterator beginOfNextNonEmptyBucket(size_t & bucket)
@ -78,8 +84,6 @@ public:
typedef typename Impl::key_type key_type;
typedef typename Impl::value_type value_type;
static constexpr size_t NUM_BUCKETS = 256;
static constexpr size_t MAX_BUCKET = NUM_BUCKETS - 1;
Impl impls[NUM_BUCKETS];

36
dbms/src/Common/tests/parallel_aggregation2.cpp
View File

@ -21,7 +21,6 @@
typedef UInt64 Key;
typedef UInt64 Value;
typedef std::vector<Key> Source;
@ -136,7 +135,7 @@ struct MergeSequential
};
template <typename Map>
struct MergeSequentialTransposed
struct MergeSequentialTransposed /// На практике не лучше обычного.
{
template <typename Merger>
static void NO_INLINE execute(Map ** source_maps, size_t num_maps, Map *& result_map,
@ -250,9 +249,8 @@ struct Work
};
typedef HashMap<Key, Value> Map;
typedef TwoLevelHashMap<Key, Value> MapTwoLevel;
typedef HashMap<Key, Value, HashCRC32<Key>> Map;
typedef TwoLevelHashMap<Key, Value, HashCRC32<Key>> MapTwoLevel;
typedef Poco::FastMutex Mutex;
@ -379,20 +377,6 @@ int main(int argc, char ** argv)
MergeParallelForTwoLevelTable<MapTwoLevel, MergeSequential<MapTwoLevel::Impl>>
>::execute(data, num_threads, creator, updater, merger, pool);
if (!method || method == 11)
Work<
MapTwoLevel,
AggregateIndependent<MapTwoLevel>,
MergeParallelForTwoLevelTable<MapTwoLevel, MergeSequential<MapTwoLevel::Impl>>
>::execute(data, num_threads, creator, updater, merger, pool);
if (!method || method == 12)
Work<
MapTwoLevel,
AggregateIndependentWithSequentialKeysOptimization<MapTwoLevel>,
MergeParallelForTwoLevelTable<MapTwoLevel, MergeSequential<MapTwoLevel::Impl>>
>::execute(data, num_threads, creator, updater, merger, pool);
if (!method || method == 13)
Work<
MapTwoLevel,
@ -407,19 +391,5 @@ int main(int argc, char ** argv)
MergeParallelForTwoLevelTable<MapTwoLevel, MergeSequentialTransposed<MapTwoLevel::Impl>>
>::execute(data, num_threads, creator, updater, merger, pool);
if (!method || method == 15)
Work<
MapTwoLevel,
AggregateIndependent<MapTwoLevel>,
MergeParallelForTwoLevelTable<MapTwoLevel, MergeSequentialTransposed<MapTwoLevel::Impl>>
>::execute(data, num_threads, creator, updater, merger, pool);
if (!method || method == 16)
Work<
MapTwoLevel,
AggregateIndependentWithSequentialKeysOptimization<MapTwoLevel>,
MergeParallelForTwoLevelTable<MapTwoLevel, MergeSequentialTransposed<MapTwoLevel::Impl>>
>::execute(data, num_threads, creator, updater, merger, pool);
return 0;
}