Re: We really ought to do something about O_DIRECT and data=journalled on ext4

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Dunstan <andrew@dunslane.net>
Cc: Josh Berkus <josh@agliodbs.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2010-12-01T04:17:05Z
Lists: pgsql-hackers
Andrew Dunstan <andrew@dunslane.net> writes:
> On 11/30/2010 10:09 PM, Tom Lane wrote:
>> We should wait for the outcome of the discussion about whether to change
>> the default wal_sync_method before worrying about this.

> we've just had a significant PGX customer encounter this with the latest 
> Postgres on Redhat's freshly released flagship product. Presumably the 
> default wal_sync_method will only change prospectively.

I don't think so.  The fact that Linux is changing underneath us is a
compelling reason for back-patching a change here.  Our older branches
still have to be able to run on modern OS versions.  I'm also fairly
unclear on what you think a fix would look like if it's not effectively
a change in the default.

(Hint: this *will* be changing, one way or another, in Red Hat's version
of 8.4, since that's what RH is shipping in RHEL6.)

			regards, tom lane