Re: Backup throttling

On Tue, Aug 20, 2013 at 2:37 AM, Heikki Linnakangas
<hlinnakangas(at)vmware(dot)com> wrote:
> Throttling in the client seems much better to me. TCP is designed to handle
> a slow client.

Other people have already offered some good points in this area, but
let me just add one thought that I don't think has been mentioned yet.
We have a *general* need to be able to throttle server-side resource
utilization, particularly I/O. This is a problem not only for
pg_basebackup, but for COPY, CLUSTER, VACUUM, and even things like
UPDATE. Of all of those, the only one for which we currently have any
kind of a solution is VACUUM. Now, maybe pg_basebackup also needs its
own special-purpose solution, but I think we'd do well to consider a
general I/O rate-limiting strategy and then consider particular needs
in the light of that framework. In that context, server-side seems
better to me, because something like CLUSTER isn't going to produce
anything that the client can effectively limit.

--
Robert Haas
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