Re: Transaction commits VS Transaction commits (with parallel) VS query mean time

On Sat, Mar 23, 2019 at 9:50 AM Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> wrote:
>
> On 2019-Mar-23, Amit Kapila wrote:
>
> > I think some users might also be interested in the write transactions
> > happened in the system, basically, those have consumed xid.
>
> Well, do they really want to *count* these transactions, or is it enough
> to keep an eye on the "age" of some XID column? Other than for XID
> freezing purposes, I don't see such internal transactions as very
> interesting.
>

That's what I also had in mind. I think doing anything more than just
fixing the count for the parallel cooperating transaction by parallel
workers doesn't seem intuitive to me. I mean if we want we can commit
the fix such that all supporting transactions by parallel worker
shouldn't be counted, but I am not able to convince myself that that
is the good fix. Instead, I think rather than fixing that one case we
should think more broadly about all the supportive transactions
happening in the various operations. Also, as that is a kind of
behavior change, we should discuss that as a separate topic.

I know what I am proposing here won't completely fix the problem Hari
is facing, but I am not sure what else we can do here which doesn't
create some form of inconsistency with other parts of the system.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com