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

On 2019-Mar-23, Amit Kapila wrote:

> On Fri, Mar 22, 2019 at 10:04 AM Alvaro Herrera
> <alvherre(at)2ndquadrant(dot)com> wrote:

> > Not count them if they're implementation details; otherwise count them.
> > For example, IMO autovacuum transactions should definitely be counted
> > (as one transaction, even if they run parallel vacuum).
>
> It appears to me that the definition of what we want to display in
> xact_commit/xact_rollback (for pg_stat_database view) is slightly
> vague. For ex. does it mean that we will show only transactions
> started by the user or does it also includes the other transactions
> started internally (which you call implementation detail) to perform
> the various operations? I think users would be more interested in the
> transactions initiated by them.

Yes, you're probably right.

> 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.

--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services