Re: using custom scan nodes to prototype parallel sequential scan - Mailing list pgsql-hackers

On 14 November 2014 01:51, David Rowley <dgrowleyml@gmail.com> wrote:

> When I mentioned this, I didn't mean to appear to be placing a road block.I
> was just bringing to the table the information that COUNT(*) + COUNT(*)
> works ok for merging COUNT(*)'s "sub totals", but AVG(n) + AVG(n) does not.
>
>  Merge functions should be a simple patch to write. If I thought there was
> going to be a use for them in this release, I'd put my hand up to put a
> patch together.

The hard part is describing and then agreeing the semantics.

If you raise a separate post on this, copy me in and I will help.

-- Simon Riggs                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services