finzelj(at)gmail(dot)com writes:
> Here is the actual delete query SQL. This doesn't but I am convinced should
> use the same Index Only Scan as above, and I wonder if it's a bug?
No, unfortunately not: the DELETE requires that each table scan return
CTID (for possible EvalPlanQual rechecks), and index-only scans can't
return columns that aren't in the index.
Although come to think of it, we necessarily get the TID from the index
AM, so in principle it should be possible for an index-only scan to
provide that column. But that's an unimplemented feature, not a bug.
regards, tom lane