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

On 11/10/16 1:03 PM, Stephen Frost wrote:
> On Thursday, November 10, 2016, Joshua D. Drake <jd(at)commandprompt(dot)com
> <mailto:jd(at)commandprompt(dot)com>> wrote:
>
> On 11/10/2016 09:33 AM, David Steele wrote:
>
> On 11/10/16 10:28 AM, Stephen Frost wrote:
>
> diff --git a/src/backend/access/transam/xlog.c
> b/src/backend/access/transam/xlog.c
>
> [...]
>
> + if (log_checkpoints)
> + ereport(LOG,
> (errmsg("checkpoint skipped")));
>
>
> Do we really need to log that we're skipping a
> checkpoint..? As the
> point of this is to avoid write activity on a system which
> is idle, it
> doesn't make sense to me to add a new cause for writes to
> happen when
> we're idle.
>
>
> log_checkpoints is not enabled by default, though, so if the
> user does
> enable it don't you think they would want to know when checkpoints
> *don't* happen?
>
>
> Yes but I don't know that it needs to be anywhere below DEBUG2 (vs
> log_checkpoints).
>
>
> 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.

--
-David
david(at)pgmasters(dot)net