From: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
---|---|
To: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Noah Misch <noah(at)leadboat(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, david(at)fetter(dot)org, aidan(at)highrise(dot)ca, stark(at)mit(dot)edu, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: 16-bit page checksums for 9.2 |
Date: | 2012-02-29 19:09:02 |
Message-ID: | 4F4E77CE.1050101@enterprisedb.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 29.02.2012 19:54, Simon Riggs wrote:
> I'm beginning to lose faith that objections are being raised at a
> rational level. It's not a panel game with points for clever answers,
> its an engineering debate about how to add features real users want.
> And they do want, so let me solve the problems by agreeing something
> early enough to allow it to be implemented, rather than just
> discussing it until we run out of time.
I thought my view on how this should be done was already clear, but just
in case it isn't, let me restate: Enlarge the page header to make room
for the checksum. To handle upgrades, put code in the backend to change
the page format from old version to new one on-the-fly, as pages are
read in. Because we're making the header larger, we need to ensure that
there's room on every page. To do that, write a utility that you run on
the cluster before running pg_upgrade, which moves tuples to ensure
that. To ensure that the space doesn't get used again before upgrading,
change the old version so that it reserves those N bytes in all new
insertions and updates (I believe that approach has been discussed
before and everyone is comfortable with backpatching such a change). All
of this in 9.3.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
From | Date | Subject | |
---|---|---|---|
Next Message | Alvaro Herrera | 2012-02-29 19:13:42 | Re: Client Messages |
Previous Message | Tom Lane | 2012-02-29 19:08:43 | Re: Parameterized-path cost comparisons need some work |