Re: Planner issue on sorting joining of two tables with limit

"Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> writes:
> Alexander Korotkov <aekorotkov(at)gmail(dot)com> wrote:
>>> I just don't find why it is coincidence. I think that such plan
>>> will always produce result ordered by two columns, because such
>>> nested index scan always produce this result.

> Assuming a nested index scan, or any particular plan, is unwise.

I think he's proposing that the planner should recognize that a plan
of this type produces a result sorted by the additional index columns.
I'm not convinced either that the sortedness property really holds,
or that it would be worth the extra planning effort to check for;
but it's not a fundamentally misguided proposal.

regards, tom lane