Re: [PERFORM] encouraging index-only scans

On Tue, Feb 11, 2014 at 06:54:10PM +0100, Andres Freund wrote:
> On 2014-02-11 12:12:13 -0500, Bruce Momjian wrote:
> > Yes, that pretty much sums it up.  We introduced index-only scans in 9.2
> > (2012) but they still seem to be not usable for insert-only workloads
> > two years later.  Based on current progress, it doesn't look like this
> > will be corrected until 9.5 (2015).  I am kind of confused why this has
> > not generated more urgency.
> 
> I think this largely FUD. They are hugely beneficial in some scenarios
> and less so in others. Just like lots of other features we have.

I don't understand.  Index-only scans are known to have benefits --- if
an insert-only workload can't use that, why is that acceptable?  What is
fear-uncertainty-and-doubt about that?  Please explain.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + Everyone has their own god. +