MIME-Version: 1.0
References: <20190516182628.kbkiajfnlooocgyg@momjian.us>
 <20190516190806.GA14121@alvherre.pgsql>
 <CAH2-WzkkJWHiY-Uqmd4L2L5YKiPDW02ach478KXb12gmFcQGtg@mail.gmail.com>
 <20190516235250.GD20887@paquier.xyz>
In-Reply-To: <20190516235250.GD20887@paquier.xyz>
From: Peter Geoghegan <pg@bowt.ie>
Date: Thu, 16 May 2019 17:05:13 -0700
Message-ID: 
 <CAH2-WznHtAuCcRMrNcocKNy1vN4w4e88d2XCT1fMMFnzjd-KiA@mail.gmail.com>
Subject: Re: PostgreSQL 12: Feature Highlights
To: Michael Paquier <michael@paquier.xyz>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>,
 Bruce Momjian <bruce@momjian.us>,
	Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>,
 David Rowley <david.rowley@2ndquadrant.com>,
	"Jonathan S. Katz" <jkatz@postgresql.org>,
	PostgreSQL Advocacy <pgsql-advocacy@lists.postgresql.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Thu, May 16, 2019 at 4:52 PM Michael Paquier <michael@paquier.xyz> wrote:
> +1.  Another thing which may matter is that if some people do not see
> some improvements they were expecting then they can come back to pg13
> and help around with having these added.  Things are never going to be
> perfect for all users, and it makes little sense to make it sound like
> things are actually perfect.

Speaking of imperfections: it is well known that most performance
enhancements have the potential to hurt certain workloads in order to
help others. Maybe that was explicitly considered to be a good
trade-off when the feature went in, and maybe that was the right
decision at the time, but more often it was something that was simply
overlooked. There is value in leaving information that helps users
discover where a problem may have been introduced -- they can tell us
about it, and we can fix it.

I myself sometimes look through the release notes in an effort to spot
something that might have had undesirable side-effects, especially in
areas of the code that I am less knowledgeable about, or have only a
vague recollection of. Sometimes that is a reasonable starting point.

-- 
Peter Geoghegan