I think Chimay's proposal could make application more clear and increase the performance as locate of key/window cost most of time.
A suggested usage for Composite Accumulation could as following: * //following is the sample code how to add sub accumulations* * CompositeAccumulation<Long> accumulations = new CompositeAccumulation<>();* * AccumulationTag sumTag = accumulations.addAccumulation((Accumulation)new SumAccumulation());* * AccumulationTag countTag = accumulations.addAccumulation((Accumulation)new Count());* * AccumulationTag maxTag = accumulations.addAccumulation(new Max());* * AccumulationTag minTag = accumulations.addAccumulation(new Min());* * //following is the sample how to get the sub-accumulation output* * accumulations.getSubOutput(sumTag, outputValues)* * accumulations.getSubOutput(countTag, outputValues)* * accumulations.getSubOutput(maxTag, outputValues)* * accumulations.getSubOutput(minTag, outputValues)* Thanks Bright On Sun, Feb 26, 2017 at 10:33 PM, Chinmay Kolhatkar <chin...@datatorrent.com > wrote: > Dear Community, > > Currently we have accumulations for individual types of accumulations. > But if one wants to do more than one accumulations in a single stage of > Windowed Operator it is not possible. > > I want to propose an idea about "CompositeAccumulation" where more than one > accumulation can be configured and this accoumulation can relay on multiple > accumulations to generate final result/output. > > The output can be either of the 2 forms: > 1. Just the list of outputs with AccumulationTags as identifiers. > 2. Merge the results of multiple accumulations using some user defined > logic. > For eg. In aggregation case, Input POJO to this accumulation can be a > POJO containing NumberOfOrders as field and in output one might need to > generate a final(single) POJO which contains result of multiple > accumulations like SUM, COUNT on NumberOfOrders as different fields of > outgoing POJO. > > I particularly see the use of this for Multiple Aggregation which we would > like to do in SQL on Apex Integration. > > Please share your thoughts on the same. > > Thanks, > Chinmay. >
