On Tue, 2020-04-28 at 11:57 -0400, Jonah H. Harris wrote:
> Yeah, in that specific case, one of the other implementations seems
> to carry the counters along in the executor itself. But, as not all
> uses of this functionality are iteration-count-based, I think that's
> a little limiting. Using a terminator expression (of some kind) seems
> most adaptable, I think. I'll give some examples of both types of
> cases.
In my experience, graph algorithms or other queries doing more
specialized analysis tend to get pretty complex with lots of special
cases. Users may want to express these algorithms in a more familiar
language (R, Python, etc.), and to version the code (probably in an
extension).
Have you considered taking this to the extreme and implementing
something like User-Defined Table Operators[1]? Or is there a
motivation for writing such algorithms inline in SQL?
Regards,
Jeff Davis
[1] http://www.vldb.org/conf/1999/P47.pdf