Re: Set new system identifier using pg_resetxlog

Robert Haas wrote:
> On Mon, Jun 30, 2014 at 12:46 PM, Alvaro Herrera
> <alvherre(at)2ndquadrant(dot)com> wrote:
> > I think it's pretty much a given that pg_resetxlog is a tool that can
> > have disastrous effects if used lightly. If people changes their sysid
> > wrongly, they're not any worse than if they change their multixact
> > counters and start getting failures because the old values stored in
> > data cannot be resolved anymore ("it's already been wrapped around").
> > Or if they remove all the XLOG they have since the latest crash. From
> > that POV, I don't think the objection that "but this can be used to
> > corrupt data!" has any value.
>
> After thinking about this a little more, I guess I don't really think
> it's a bit problem either - so consider my objection withdrawn.

Great.

> I am, however, kind of frustrated, still, that the pg_computemaxlsn
> patch, which I thought was rather a good idea, was scuttled by the
> essentially that same objection: let's not extend pg_resetxlog &
> friends because people might use the new functionality to do bad
> things and then blame us.

Uh, I thought you killed that patch yourself:
http://www.postgresql.org/message-id/CA+TgmoZqbYHWYbi18FUk-+dGHig=icV+pj-NNav3miy4dajgrQ@mail.gmail.com

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