Re: What's the XID?

[Jeff Frost <jeff(at)frostconsultingllc(dot)com>]

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