Re: [PATCH] Negative Transition Aggregate Functions (WIP)

On Fri, Jan 17, 2014 at 3:05 PM, Florian Pflug <fgp(at)phlo(dot)org> wrote:

> I had some more fun with this, the result is v2.5 of the patch (attached).
> Changes are explained below.
>
>
Looks like you've been busy on this! Thank you for implementing all the
changes you talked about.
I've now started working the 2.5 patch you sent and I've ripped out all the
numeric inverse transition functions on that patch and implemented inverse
transitions for max and min using the new NULL returning method that you've
implemented. I've also made a very fast pass and fixed up a few comments
and some random white space. I've not gotten to the documents yet.

I did add a whole bunch of regression tests for all of the inverse
transition functions that are used for max and min. I'm just calling these
like:
SELECT int4larger_inv(3,2),int4larger_inv(3,3),int4larger_inv(3,4);
Rather than using the aggregate as a window function each time. I thought
it was better to validate each of those functions individually then put in
various tests that target a smaller number of aggregates with various
inputs.

A few things still to do that I'll try and get to soon.
1. More testing
2. Docs updated.
3. Perhaps I'll look at adding bitand and bitor inverse transition functions
4. ?

Thanks again for putting so much effort into this.
If you make any more changes would it be possible for you to base them on
the attached patch instead of the last one you sent?

Perhaps if there's much more hacking to do we could start pushing to a
guthub repo to make it easier to work together on this.

Regards

David Rowley