mirror of
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95 lines
3.2 KiB
C++
95 lines
3.2 KiB
C++
#include <AggregateFunctions/AggregateFunctionFactory.h>
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#include <AggregateFunctions/AggregateFunctionTopK.h>
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#include <AggregateFunctions/Helpers.h>
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#include <AggregateFunctions/FactoryHelpers.h>
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#include <DataTypes/DataTypeDate.h>
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#include <DataTypes/DataTypeDateTime.h>
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#define TOP_K_MAX_SIZE 0xFFFFFF
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
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extern const int ARGUMENT_OUT_OF_BOUND;
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}
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namespace
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{
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/// Substitute return type for Date and DateTime
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class AggregateFunctionTopKDate : public AggregateFunctionTopK<DataTypeDate::FieldType>
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{
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using AggregateFunctionTopK<DataTypeDate::FieldType>::AggregateFunctionTopK;
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DataTypePtr getReturnType() const override { return std::make_shared<DataTypeArray>(std::make_shared<DataTypeDate>()); }
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};
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class AggregateFunctionTopKDateTime : public AggregateFunctionTopK<DataTypeDateTime::FieldType>
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{
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using AggregateFunctionTopK<DataTypeDateTime::FieldType>::AggregateFunctionTopK;
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DataTypePtr getReturnType() const override { return std::make_shared<DataTypeArray>(std::make_shared<DataTypeDateTime>()); }
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};
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static IAggregateFunction * createWithExtraTypes(const DataTypePtr & argument_type, UInt64 threshold)
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{
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WhichDataType which(argument_type);
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if (which.idx == TypeIndex::Date) return new AggregateFunctionTopKDate(threshold);
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if (which.idx == TypeIndex::DateTime) return new AggregateFunctionTopKDateTime(threshold);
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/// Check that we can use plain version of AggregateFunctionTopKGeneric
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if (argument_type->isValueUnambiguouslyRepresentedInContiguousMemoryRegion())
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return new AggregateFunctionTopKGeneric<true>(threshold, argument_type);
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else
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return new AggregateFunctionTopKGeneric<false>(threshold, argument_type);
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}
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AggregateFunctionPtr createAggregateFunctionTopK(const std::string & name, const DataTypes & argument_types, const Array & params)
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{
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assertUnary(name, argument_types);
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UInt64 threshold = 10; /// default value
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if (!params.empty())
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{
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if (params.size() != 1)
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throw Exception("Aggregate function " + name + " requires one parameter or less.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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UInt64 k = applyVisitor(FieldVisitorConvertToNumber<UInt64>(), params[0]);
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if (k > TOP_K_MAX_SIZE)
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throw Exception("Too large parameter for aggregate function " + name + ". Maximum: " + toString(TOP_K_MAX_SIZE),
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ErrorCodes::ARGUMENT_OUT_OF_BOUND);
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if (k == 0)
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throw Exception("Parameter 0 is illegal for aggregate function " + name,
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ErrorCodes::ARGUMENT_OUT_OF_BOUND);
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threshold = k;
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}
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AggregateFunctionPtr res(createWithNumericType<AggregateFunctionTopK>(*argument_types[0], threshold));
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if (!res)
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res = AggregateFunctionPtr(createWithExtraTypes(argument_types[0], threshold));
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if (!res)
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throw Exception("Illegal type " + argument_types[0]->getName() +
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" of argument for aggregate function " + name, ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
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return res;
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}
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}
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void registerAggregateFunctionTopK(AggregateFunctionFactory & factory)
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{
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factory.registerFunction("topK", createAggregateFunctionTopK);
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}
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}
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