"Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> writes:
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> It would be worth checking whether you get the same plan without
>> the patch (you should, but let's check).
> Same plan.
Yeah, I just managed to reproduce a similar behavior in unpatched HEAD.
Now, since I'm running without any stats, it might be that it's
estimating similar costs for the one-key and two-key merges; but I don't
see why that would happen for you. Off to do some debugging.
regards, tom lane