Re: Index only scan and ctid

On Mon, 2020-02-03 at 14:43 -0500, Tom Lane wrote:
> Laurenz Albe <laurenz.albe@cybertec.at> writes:
> > I noticed that "ctid" in the select list prevents an index only scan:
> > This strikes me as strange, since every index contains "ctid".
> 
> There's no provision for an IOS to return a system column, though.
> Not sure what it'd take to make that possible.

I was reminded what the obvious problem is:
the ctid of a heap only tuple is not stored in the index.  Duh.

Yours,
Laurenz Albe