From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Andres Freund <andres@anarazel.de>,
        Michael Paquier <michael.paquier@gmail.com>,
        Masahiko Sawada <sawada.mshk@gmail.com>,
        "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: Reviewing freeze map code
In-reply-to: 
 <CA+TgmoZjbpb5SGWy-3qDgQm5b4XxfpKrBzDuHmQ3gvT4nRD6tw@mail.gmail.com>
References: 
 <CAD21AoBL0HPaWM4ZkLmd_h2c1DAS-J9KrxbwqSd7no3XYVCRSw@mail.gmail.com>
 <CA+TgmoZ1k4jnbkZTnbRmCA4T1RVGd0dqaHm6Y0RoT2knN6qm_A@mail.gmail.com>
 <CAD21AoCTLAu2niddmUVd2Y1p0OVWgGnT51_+J81=qb3HAwVtFQ@mail.gmail.com>
 <CA+TgmobpQLGh7YH_gN+Y=L7J-W0XeWfH5_qiAs0a+Xp7H4uS=g@mail.gmail.com>
 <CAD21AoDo5DOQJXUw_gw0kwJm+q0ux_fMgWGC6tkthZFWR+CxKw@mail.gmail.com>
 <CA+TgmoZqMxB6Cyj7_2=SH=WyEBJBsrRW9ioTQvWju9Sw4rRcZw@mail.gmail.com>
 <CAD21AoA8XwpyrakFZHrX8+mfySk7y6gHh4+D-ZGA-R9Axx_PJg@mail.gmail.com>
 <CAD21AoDBzsdiCxQ0SaOswACEUM92Fe2+1ipmVb4Ma6NAgQFnjg@mail.gmail.com>
 <CAB7nPqRW7pgPbNbYAX_mmP0QRg1iHt068oVVBOX3djD+_rVUug@mail.gmail.com>
 <CA+TgmoZ3Q3ypceH-QT4qhaVyPQACgDoUugGna2MXDw3AE6HpNQ@mail.gmail.com>
 <20160606152808.qnkmjixskxq5vtoo@alap3.anarazel.de>
 <CA+TgmoZjbpb5SGWy-3qDgQm5b4XxfpKrBzDuHmQ3gvT4nRD6tw@mail.gmail.com>
Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Mon, 06 Jun 2016 11:37:25 -0400"
Date: Mon, 06 Jun 2016 11:45:02 -0400
Message-ID: <22317.1465227902@sss.pgh.pa.us>
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org

Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Jun 6, 2016 at 11:28 AM, Andres Freund <andres@anarazel.de> wrote:
>> Except that we right now don't have any realistic way to figure out
>> whether this new feature actually does the right thing.

> I just don't see how running VACUUM on the all-frozen pages is going
> to help.

Yes.  I don't see that any of the proposed features would be very useful
for answering the question "is my VM incorrect".  Maybe they would fix
problems, and maybe not, but in any case you couldn't rely on VACUUM
to tell you about a problem.  (Even if you've got warning messages in
there, they might disappear into the postmaster log during an
auto-vacuum.  Warning messages in VACUUM are not a good debugging
technology.)

			regards, tom lane


-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers