Re: UNION ALL has higher cost than inheritance

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Mon, Nov 8, 2010 at 1:19 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> But this all looks like a pretty substantial amount of work, and
>> given the low level of user demand for improving the performance of
>> set operations, it seems to belong fairly far down the to-do list.
>> So I'm not going to tackle it now. Barring objection, I'll clean up
>> yesterday's patch a bit more and commit it.

> I agree. If we had infinite resources it would be nice to tackle
> this, but I think we have bigger fish to fry. In particular, I wonder
> if you've thought any more about the generalized inner-indexscan
> machinery, or taken a look at any of the issues around KNNGIST. I'd
> like to see our limited supply of planner-fu invested in those areas,
> or perhaps in making inner join removal work.

The two top things on my to-do list for 9.1 are the generalized
inner-indexscan stuff and automatic replans for parameterized queries.
I had been hoping to finish one or the other before the next commitfest,
though time is draining away rapidly.

I'll try to look at KNNGIST during the fest.

regards, tom lane