class xf::database::gqe::Aggregator¶

#include "xf_database/gqe_aggr.hpp"

Overview¶

Methods¶

Aggregator¶

Aggregator (std::string xclbin)

construct of Aggregator .

Parameters:

xclbin

xclbin path

aggregate¶

ErrCode aggregate (
    Table& tab_in,
    std::vector <EvaluationInfo> evals_info,
    std::string filter_str,
    std::string group_keys_str,
    std::string output_str,
    Table& tab_out,
    AggrStrategyBase* strategyImp = nullptr
    )

aggregate function.

Usage:

err_code = bigaggr.aggregate(tab_l, //input table
                             {{"l_extendedprice * (-l_discount+c2) / 100", {0, 100}},
                              {"l_extendedprice * (-l_discount+c2) * (l_tax+c3) / 10000", {0, 100, 100}}
                             }, // evaluation
                             "l_shipdate<=19980902", //filter
                             "l_returnflag,l_linestatus", // group keys
                             "c0=l_returnflag, c1=l_linestatus,c2=sum(eval0),c3=sum(eval1)", // mapping
                             tab_c, //output table
                             sptr); //strategy

Input filter_str like “19940101<=o_orderdate && o_orderdate<19950101”, o_orderdate and o_orderdate must be exsisted colunm names in input table when no filter conditions, input “”

Input evaluation information as a struct EvaluationInfo , creata a valid Evaluation struct using initializer list, e.g. {“l_extendedprice * (-l_discount+c2) / 100”, {0, 100}} EvaluationInfo has two members: evaluation string and evaluation constants. In the evaluation string, you can input a final division calculation. Divisor only supports: 10,100,1000,10000 In the evaluation constants, input a constant for each column, if no constant, like “l_extendedprice” above, input zero.

Input Group keys in a string, like “group_key0, group_key1”, use comma as seperator

Output strings are like “c0=tab_in_col1, c1=tab_in_col2”, when contains several columns, use comma as seperator

StrategyImp class pointer of derived class of AggrStrategyBase .

Parameters:

tab_in	input table
evals_info	Evalutaion information
filter_str	filter condition
group_keys_str	group keys
out_ptr	output list, output1 = tab_a_col1
tab_out	result table
strategyImp	pointer to an object of AggrStrategyBase or its derived type.