Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> AFAICS this should be safe. In fact, in 8.3 TRUNCATE advances
> relfrozenxid. (Perhaps you should consider upgrading if possible.)
> ...
> Tou could just obtain the xid of the transaction that's going to do the
> import (for example by creating a temp table and getting it's xmin from
> pg_class)
That seems a bit risky. 8.3 resets relfrozenxid to RecentXmin, not the
current transaction's XID. The OP's thought of taking the max existing
relfrozenxid should be safe though.
Or I guess you could make a temp table and take the relfrozenxid, rather
than the xmin, from its pg_class entry.
regards, tom lane