Re: Set new system identifier using pg_resetxlog

On Mon, Jun 30, 2014 at 12:46 PM, Alvaro Herrera
<alvherre@2ndquadrant.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it's a bit problem either - so consider my objection withdrawn.

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.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company