Re: Transaction id wraparound questions

Marc Munro <marc(at)bloodnok(dot)com> writes:
> A recent vacuum of the entire database gave us the dreaded
> "You may have already suffered transaction-wraparound data loss."
> warning.

If you have in fact been vacuuming *every* table including all the
system catalogs, then you don't need to panic; this message just
indicates that the system doesn't know you're safe.

On the other hand, if you haven't ...

> 2) Will a full database vacuum fix the problem?

If it's fixable. I would recommend that you do this IMMEDIATELY,
rather than dithering, as every transaction you execute is taking
you one step closer to disaster.

> 3) Can it make things worse?
> 4) Other than dump and restore, what options do we have?

If you can conveniently take a full dump, that might give you some
measure of protection, but I'm not sure. I think that if there is
anything that's already wrapped around, pg_dump will not see it :-(

regards, tom lane