On 2017-04-25 13:11:32 -0400, Bruce Momjian wrote:
> On Tue, Apr 25, 2017 at 01:37:13PM -0300, Claudio Freire wrote:
> > The truncate scan has been measured to be five times faster than without
> > this patch (that was on a slow disk, but it shouldn't hurt on fast
> > disks.)
> >
> > Author: Álvaro Herrera, loosely based on a submission by Claudio Freire
> > Discussion:
> > https://postgr.es/m/CAGTBQpa6NFGO_6g_y_7zQx8L9GcHDSQKYdo1tGuh791z6PYgEg@mail.gmail.com
>
> I don't think this warrants inclusion in the release notes for reasons
> already discussed. The vacuum truncation operation is a rare one and
> an implementation detail.
I think that's backwards. The truncate operation is quite delicate
because it happens with AccessExclusiveLock held. This regularly does
cause issues in production. When users look for things they possibly
should update for, something like "performance improvents in final
vacuum phase" + oneliner is going to be a lot more interesting than,
say, "Add MONEY operators for multiplication and division with INT8
values".
More and more users are going to be primarily interested in three
classes of new things in postgres: 1) performance 2) replication 3)
easier management. Arbitrarily excluding one of the major categories
from release notes isn't a useful policy, especially if we continue to
list new feature that'll effect no more than a handful of people.
- Andres