Re: Patch: Write Amplification Reduction Method (WARM)

On Tue, Mar 21, 2017 at 09:25:49AM -0400, Robert Haas wrote:
> On Tue, Mar 21, 2017 at 8:41 AM, Pavan Deolasee
> > TBH I see many artificial scenarios here. It will be very useful if he can
> > rerun the query with some of these restrictions lifted. I'm all for
> > addressing whatever we can, but I am not sure if this test demonstrates a
> > real world usage.
>
> That's a very fair point, but if these patches - or some of them - are
> going to get committed then these things need to get discussed. Let's
> not just have nothing-nothing-nothing giant unagreed code drop.

First, let me say I love this feature for PG 10, along with
multi-variate statistics.

However, not to be a bummer on this, but the persistent question I have
is whether we are locking ourselves into a feature that can only do
_one_ index-change per WARM chain before a lazy vacuum is required. Are
we ever going to figure out how to do more changes per WARM chain in the
future, and is our use of so many bits for this feature going to
restrict our ability to do that in the future.

I know we have talked about it, but not recently, and if everyone else
is fine with it, I am too, but I have to ask these questions.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ As you are, so once was I. As I am, so you will be. +
+ Ancient Roman grave inscription +