Re: Partial aggregates pushdown

Tomas Vondra писал 2021-10-15 17:56:
> Hi Alexander,
> 

Hi.

> And then we should extend this for aggregates with more complex
> internal states (e.g. avg), by supporting a function that "exports"
> the aggregate state - similar to serial/deserial functions, but needs
> to be portable.
> 
> I think the trickiest thing here is rewriting the remote query to call
> this export function, but maybe we could simply instruct the remote
> node to use a different final function for the top-level node?
> 
> 

If we have some special export function, how should we find out that 
remote server supports this? Should it be server property or should it 
somehow find out it while connecting to the server?

-- 
Best regards,
Alexander Pyhalov,
Postgres Professional