On 2013-12-02 09:59:12 -0500, Tom Lane wrote:
> Andres Freund <andres@2ndquadrant.com> writes:
> > I think we also needs support for testing xid/multixid wraparound. It
> > currently isn't realistically testable because of the timeframes
> > involved.
>
> When I've wanted to do that in the past, I've used pg_resetxlog to
> adjust a cluster's counters.
I've done that as well, but it's painful and not neccessarily testing
the right thing. E.g. I am far from sure we handle setting the
anti-wraparound limits correctly when promoting a standby - a restart to
adapt pg_control changes things and it might get rolled back because of
a already logged checkpoints.
What I'd love is a function that gives me the opportunity to
*efficiently* move forward pg_clog, pg_multixact/offset,members by large
chunks. So e.g. I could run a normal pgbench alongside another pgbench
moving clog forward in 500k chunks, but so it creates the necessary
files I could possibly need to access.
If you do it naivly you get into quite some fun with hot standby btw. I
can tell you that from experience :P
Greetings,
Andres Freund
-- Andres Freund http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services