Re: Fix checkpoint skip logic on idle systems by tracking LSN progress

Thank you for the new patch.

At Fri, 11 Nov 2016 16:42:43 +0900, Michael Paquier <michael(dot)paquier(at)gmail(dot)com> wrote in <CAB7nPqR73vusv5kQgZzket5mLZLeEcgNF-3hKh7061QtcZiuVw(at)mail(dot)gmail(dot)com>
> On Fri, Nov 11, 2016 at 12:28 AM, Stephen Frost <sfrost(at)snowman(dot)net> wrote:
> > We should probably include in here that we may skip a checkpoint if no
> > activity has happened, meaning that this is a safe setting to set for
> > environments which are idle for long periods.
>
> OK, here is the interesting bit I just updated (I cut the diff a bit
> as the rest is just reformatting):
> parameter is greater than zero, the server will switch to a new
> segment file whenever this many seconds have elapsed since the last
> segment file switch, and there has been any database activity,
> - including a single checkpoint. (Increasing
> - <varname>checkpoint_timeout</> will reduce unnecessary
> - checkpoints on an idle system.)
> [...]
> + including a single checkpoint. Checkpoints can however be skipped
> + if there is no database activity, making this parameter a safe
> + setting for environments which are idle for a long period of time.
>
> > (I'm thinking embedded systems here).
>
> (Those are most of my users :{) ).

Ok, (FWIW..,) it seems fine for me.

> On Fri, Nov 11, 2016 at 3:23 AM, David Steele <david(at)pgmasters(dot)net> wrote:
> > On 11/10/16 1:03 PM, Stephen Frost wrote:
> >> Agreed. You certainly may wish to log checkpoints, even on an embedded
> >> or low I/o system, but logging that nothing is happening doesn't seem
> >> useful except perhaps for debugging.
> >
> > Sure, DEBUG1 or DEBUG2 makes sense.
>
> OK. LOG was useful to avoid noise when debugging the thing, but DEBUG1
> is fine for me as well in the final version.

Agreed. DEBUG2 seems too deep for it.

Well, I think we had the final comment and it has been addressd
so I mark this as ready for committer soon.

Thank you all.

--
Kyotaro Horiguchi
NTT Open Source Software Center