Hi again, Any suggestions on this? Or anyone I can reach to who are not on this list or not active on the list?
Thank you. On 17 July 2017 at 17:18, Riyafa Abdul Hameed <[email protected]> wrote: > Hi again, > > I think I can understand how to write the descriptor in the packages: > org.apache.asterix.runtime.aggregates.std and > org.apache.asterix.runtime.aggregates.scalar. > But I am not sure I understand how to write the descriptor in the package: > org.apache.asterix.runtime.aggregates.serializable.std because it > requires setting a state in the init function that doesn't seem to have a > pattern in the other descriptors. > Also I don't seem to understand the reasons for implementing each of these > descriptors for the aggregate functions. > > On 17 July 2017 at 16:56, Riyafa Abdul Hameed <[email protected]> > wrote: > >> Hi all, >> >> I meant any explanation on the implementation of aggregate functions in >> AsterixDB would be highly appreciated. >> >> Thank you. >> Yours sincerely, >> Riyafa >> >> On 16 July 2017 at 08:01, Riyafa Abdul Hameed <[email protected]> wrote: >> >>> Dear all, >>> >>> I am trying to create aggregate functions and I see there are more than >>> one function descriptors for one single function. >>> For example the function array_count(collection) has the following >>> descriptors: >>> >>> >>> - ScalarCountAggregateDescriptor >>> - SerializableCountAggregateDescriptor >>> - CountAggregateDescriptor >>> >>> I am not sure I understand the difference between each of this. Can you >>> please provide and example or point me to a documentation entry to learn >>> how to properly implement aggregate functions? >>> >>> The function I am trying to implement is ST_Extent. >>> <https://postgis.net/docs/manual-1.4/ST_Extent.html> >>> >>> Thank you. >>> >>> Yours sincerely, >>> >>> Riyafa >>> >> >> >> >> -- >> Riyafa Abdul Hameed >> Undergraduate, University of Moratuwa >> >> Email: [email protected] >> Website: https://riyafa.wordpress.com/ <http://riyafa.wordpress.com/> >> <http://facebook.com/riyafa.ahf> <http://lk.linkedin.com/in/riyafa> >> <http://twitter.com/Riyafa1> >> > >
