Skip site navigation (1) Skip section navigation (2)

Re: 16-bit page checksums for 9.2

From: Simon Riggs <simon(at)2ndQuadrant(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Andres Freund <andres(at)anarazel(dot)de>, Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, 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: 2012-01-07 10:14:30
Message-ID: CA+U5nMKRjLgogD=BihP5jnuhmOAbU_y_ZZr5z+xELzXJQQ8xRw@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-hackers
On Fri, Jan 6, 2012 at 9:44 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:

>> Writing pages during recovery doesn't need WAL. If we crash, we replay
>> using the already generated WAL.
>
> Which is all fine, except when you start making changes that are not
> WAL-logged.  Then, you have the same torn page problem that exists
> when you it in normal running.

Yes, of course. My point is that this is not a blocker to using
checksums, only that some actions cannot occur on the standby but the
replay of changes is not in danger.

page_checksums is an optional parameter, so you can turn it on or off
on the standby as you wish. People frequently have a standby dedicated
to HA and other standbys for queries. So this is all normal and
natural.

page_checksums will default to 'off' in the final patch anyway, in my
understanding.

-- 
 Simon Riggs                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

In response to

Responses

pgsql-hackers by date

Next:From: Simon RiggsDate: 2012-01-07 10:24:38
Subject: Re: LWLOCK_STATS
Previous:From: Heikki LinnakangasDate: 2012-01-07 09:31:04
Subject: Re: Moving more work outside WALInsertLock

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group