Re: Index only scan and ctid - Mailing list pgsql-hackers

From Laurenz Albe
Subject Re: Index only scan and ctid
Date
Msg-id 39d8715e58e0aaffc0295628270f6e0be6db68a2.camel@cybertec.at
Whole thread Raw
In response to Re: Index only scan and ctid  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Index only scan and ctid
List pgsql-hackers
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




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