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AggregateFunctionTopK: smaller initial table size

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By default start with 2^4 elements
This commit is contained in:
Marek Vavruša 2017-05-12 13:38:03 -07:00 committed by alexey-milovidov
parent 74cc0849dc
commit 95d926ec14
1 changed files with 8 additions and 7 deletions
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15
dbms/src/AggregateFunctions/AggregateFunctionTopK.h
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@ -21,8 +21,8 @@ namespace DB
// Allow NxK more space before calculating top K to increase accuracy
#define TOP_K_DEFAULT 10
#define TOP_K_LOAD_FACTOR 3
#define TOP_K_DEFAULT_DEGREE 10
#define TOP_K_MAX_SIZE 0xFFFFFF
@ -34,8 +34,8 @@ struct AggregateFunctionTopKData
T,
T,
HashCRC32<T>,
HashTableGrower<TOP_K_DEFAULT_DEGREE>,
HashTableAllocatorWithStackMemory<sizeof(T) * (1 << (TOP_K_DEFAULT_DEGREE/2))>
HashTableGrower<4>,
HashTableAllocatorWithStackMemory<sizeof(T) * (1 << 4)>
>;
Set value;
};
@ -47,7 +47,7 @@ class AggregateFunctionTopK
{
private:
using State = AggregateFunctionTopKData<T>;
size_t threshold = TOP_K_DEFAULT_DEGREE;
size_t threshold = TOP_K_DEFAULT;
size_t reserved = TOP_K_LOAD_FACTOR * threshold;
public:
@ -132,8 +132,8 @@ struct AggregateFunctionTopKGenericData
std::string,
StringRef,
StringRefHash,
HashTableGrower<TOP_K_DEFAULT_DEGREE>,
HashTableAllocatorWithStackMemory<sizeof(StringRef) * (1 << (TOP_K_DEFAULT_DEGREE/2))>
HashTableGrower<4>,
HashTableAllocatorWithStackMemory<sizeof(StringRef) * (1 << 4)>
>;
Set value;
@ -148,7 +148,7 @@ class AggregateFunctionTopKGeneric : public IUnaryAggregateFunction<AggregateFun
private:
using State = AggregateFunctionTopKGenericData;
DataTypePtr input_data_type;
size_t threshold = TOP_K_DEFAULT_DEGREE;
size_t threshold = TOP_K_DEFAULT;
size_t reserved = TOP_K_LOAD_FACTOR * threshold;
static void deserializeAndInsert(StringRef str, IColumn & data_to);
@ -254,6 +254,7 @@ inline void AggregateFunctionTopKGeneric<true>::deserializeAndInsert(StringRef s
}
#undef TOP_K_DEFAULT
#undef TOP_K_MAX_SIZE
#undef TOP_K_LOAD_FACTOR