| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Andres Freund <andres(at)2ndquadrant(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Jim Nasby <jim(at)nasby(dot)net>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Peter Geoghegan <peter(at)2ndquadrant(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Andrew Dunstan <andrew(at)dunslane(dot)net>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: [PERFORM] encouraging index-only scans |
| Date: | 2014-02-11 18:23:19 |
| Message-ID: | 20140211182319.GF2289@momjian.us |
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| Thread: | |
| Lists: | pgsql-hackers pgsql-performance |
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(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ Everyone has their own god. +
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