Re: What's the XID?

On Thu, 27 Dec 2007, Tom Lane wrote:

> Jeff Frost <jeff(at)frostconsultingllc(dot)com> writes:
>> On Thu, 27 Dec 2007, Tom Lane wrote:
>>> But note that as of 8.3, SELECT-only transactions won't acquire an
>>> XID and hence won't advance the counter. So if you're thinking of
>>> writing code that depends on that behavior, don't.
>
>> So, the new XID counter won't advance unless there's at least one
>> INSERT/UPDATE/DELETE in the transaction? Does it also update for SELECTs that
>> call a function which does some write activity?
>
> Any "write" activity causes an XID to be acquired.
>
>> Is there a new counter (or old one that I don't know about) that keeps track
>> of the SELECT-only transactions?
>
> There's no global counter. There's a backend-local "virtual transaction
> id" counter.
>

That's a drag as I have quite a few clients who graph the xacts/sec with MRTG.
Most of these clients have read heavy workloads and it would be great to be
able to graph read vs write xacts, but a drag if you have no visibility into
the read xacts.

--
Jeff Frost, Owner <jeff(at)frostconsultingllc(dot)com>
Frost Consulting, LLC http://www.frostconsultingllc.com/
Phone: 650-780-7908 FAX: 650-649-1954