Re: log_checkpoints: count WAL segment creations from all processes

Hi Japin,

Thanks for looking into this.

On Tue, Mar 24, 2026 at 10:01 PM Japin Li <japinli(at)hotmail(dot)com> wrote:
>
>
> Hi, Xuneng
>
> On Tue, 24 Mar 2026 at 19:17, Xuneng Zhou <xunengzhou(at)gmail(dot)com> wrote:
> > Hi Zsolt,
> >
> > On Tue, Mar 24, 2026 at 1:55 PM Zsolt Parragi <zsolt(dot)parragi(at)percona(dot)com> wrote:
> >
> > Hello!
> >
> > This is a simple patch, but shouldn't it include at least some basic
> > tests verifying the new behavior?
> >
> > Thanks for looking into this. I've added a test for it. Please take a look.
>
> Thanks for updating the patch. A few comments on v2:
>
> 1.
> + (The probes listed next fire in sequence during checkpoint processing.)
> + arg0 is the number of buffers written. arg1 is the total number of
>
> These changes seem unnecessary. Additionally, there appears to be an
> indentation issue.

Yeah, I've removed these and fixed the indentation issue.

> 2.
> + current = pg_atomic_read_u64(&XLogCtl->walSegmentsCreated);
> + CheckpointStats.ckpt_segs_added = (int)
> + (current - XLogCtl->walSegsCreatedLastCheckpoint);
> + XLogCtl->walSegsCreatedLastCheckpoint = current;
>
> Is integer overflow a concern here? It seems unlikely in practice.

I don’t think overflow is a concern here, but it might still be
helpful to add some comments to mention it.

> >
> > --
> > Best,
> > Xuneng
> >
> > [4. text/x-diff; v2-0001-Count-WAL-segment-creations-by-all-processes-in-l.patch]...
>

--
Best,
Xuneng