Re: Patch for removng unused targets

> Reading between the lines of the original submission at
> <CAPpHfdtG5qoHoD+w=Tz3wC3fZ=b8i21=V5xandBFM=DTo-Yg=Q@mail.gmail.com>,
> I gather that it's the KNNGist-style case that worries you, so maybe
> it's worth applying this type of patch anyway.  I'd want to rejigger
> it to be aware of the cost implications though, at least for
> grouping_planner's choices.

Hmm.  Can we optimize for the KNN case, without causing the issues which
you warned about earlier in your post?  I'm really wary of any
"optimization" which operates completely outside of the cost model; the
ones we have (abort-early plans, for example) are already among our
primary sources of bad plan issues.

> 
> Comments?

So, Returned With Feedback, or move it to September?

-- 
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com