>> Can you please elaborate a bit?
>
> I thought that A0.Prop would ignore the composite index created on the
> columns subj and prop but this does not seem to be the case.
Yeah, I think you're barking up the wrong tree here. I think Tom had
the correct diagnosis - what do you get from "show work_mem"?
What kind of machine are you running this on? If it's a UNIX-ish
machine, what do you get from "free -m"and "uname -a"?
...Robert