On tis, 2012-03-27 at 00:53 +0100, Greg Stark wrote:
> Hm. So my original plan was dependent on adding the state-merge
> function we've talked about in the past. Not all aggregate functions
> necessarily can support such a function but I think all or nearly all
> the builtin aggregates can. Certainly min,max, count, sum, avg,
> stddev, array_agg can which are most of what people do. That would be
> a function which can take two state variables and produce a new state
> variable.
This information could also be useful to have in PL/Proxy (or similar
FDWs) to be able to integrate aggregate computation into the language.
Currently, you always have to do the state merging yourself.