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79 lines
2.3 KiB
C++
79 lines
2.3 KiB
C++
#include <AggregateFunctions/AggregateFunctionState.h>
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#include <AggregateFunctions/AggregateFunctionMerge.h>
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#include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
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#include <DataTypes/DataTypeAggregateFunction.h>
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#include "registerAggregateFunctions.h"
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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 BAD_ARGUMENTS;
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}
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namespace
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{
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class AggregateFunctionCombinatorState final : public IAggregateFunctionCombinator
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{
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public:
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String getName() const override { return "State"; }
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DataTypes transformArguments(const DataTypes & arguments) const override
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{
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return arguments;
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}
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AggregateFunctionPtr transformAggregateFunction(
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const AggregateFunctionPtr & nested_function,
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const AggregateFunctionProperties &,
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const DataTypes & arguments,
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const Array & params) const override
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{
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return std::make_shared<AggregateFunctionState>(nested_function, arguments, params);
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}
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};
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}
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void registerAggregateFunctionCombinatorState(AggregateFunctionCombinatorFactory & factory)
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{
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factory.registerCombinator(std::make_shared<AggregateFunctionCombinatorState>());
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}
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DataTypePtr AggregateFunctionState::getReturnType() const
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{
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auto ptr = std::make_shared<DataTypeAggregateFunction>(nested_func, arguments, params);
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/// Special case: it is -MergeState combinator.
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/// We must return AggregateFunction(agg, ...) instead of AggregateFunction(aggMerge, ...)
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if (typeid_cast<const AggregateFunctionMerge *>(ptr->getFunction().get()))
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{
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if (arguments.size() != 1)
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throw Exception("Combinator -MergeState expects only one argument", ErrorCodes::BAD_ARGUMENTS);
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if (!typeid_cast<const DataTypeAggregateFunction *>(arguments[0].get()))
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throw Exception("Combinator -MergeState expects argument with AggregateFunction type", ErrorCodes::BAD_ARGUMENTS);
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return arguments[0];
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}
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if (!arguments.empty())
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{
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DataTypePtr argument_type_ptr = arguments[0];
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WhichDataType which(*argument_type_ptr);
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if (which.idx == TypeIndex::AggregateFunction)
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{
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if (arguments.size() != 1)
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throw Exception("Nested aggregation expects only one argument", ErrorCodes::BAD_ARGUMENTS);
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return arguments[0];
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}
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}
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return ptr;
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}
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}
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