Re: [Postgres-xc-developers] Error Loading json_enhancements

[Koichi S. <koi...@gm...>]

Collector function is an intermediate function to collect each
datanode's aggregate function result.   For example, to calculate
avg(), coordinator needs sum() and count() result from each datanode.

Implementation example for this will be found in numeric_avg_collect()
in backend/utils/adt/numeric.c

Regards;
---
Koichi Suzuki


2014-02-02 David E. Wheeler <da...@ju...>:
> On Feb 1, 2014, at 12:12 AM, Koichi Suzuki <koi...@gm...> wrote:
>
>> You need to define collection function for an aggregate too.
>> Description will be found at
>> http://postgres-xc.sourceforge.net/docs/1_1/sql-createaggregate.html
>
> Hrm. Is there an example somewhere of how, say, a core aggregate function is ported to XC, including a collection function? Because I have no clue how to go about implementing one.
>
> Thanks,
>
> David