Re: WAL-based allocation of XIDs is insecure

Ian Lance Taylor <ian(at)airs(dot)com> writes:
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:
>> Up through 7.0, Postgres allocated XIDs a thousand at a time, and not
>> only did the not-yet-used XIDs get lost in a crash, they'd get lost in
>> a normal shutdown too. What I propose will waste XIDs in a crash but
>> not in a normal shutdown, so it's still an improvement over prior
>> versions as far as XID consumption goes.

> I find this somewhat troubling, since I like to think in terms of
> long-running systems--like, decades. But I guess it's OK (for me) if
> it is fixed in the next couple of years.

Agreed, we need to do something about the XID-wrap problem pretty soon.
But we're not solving it for 7.1, and in the meantime I don't think
these changes make much difference either way.

regards, tom lane