Re: Implement waiting for wal lsn replay: reloaded

Hi Alexander,

On Sat, Jan 3, 2026 at 6:54 AM Alexander Korotkov <aekorotkov(at)gmail(dot)com> wrote:
>
> Hi, Xuneng!
>
> On Fri, Jan 2, 2026 at 11:17 AM Xuneng Zhou <xunengzhou(at)gmail(dot)com> wrote:
> > On Fri, Jan 2, 2026 at 7:42 AM Alexander Korotkov <aekorotkov(at)gmail(dot)com> wrote:
> > >
> > > On Thu, Jan 1, 2026 at 7:16 PM Álvaro Herrera <alvherre(at)kurilemu(dot)de> wrote:
> > > > In 0002 you have this kind of thing:
> > > >
> > > > > ereport(ERROR,
> > > > > errcode(ERRCODE_QUERY_CANCELED),
> > > > > - errmsg("timed out while waiting for target LSN %X/%08X to be replayed; current replay LSN %X/%08X",
> > > > > + errmsg("timed out while waiting for target LSN %X/%08X to be %s; current %s LSN %X/%08X",
> > > > > LSN_FORMAT_ARGS(lsn),
> > > > > - LSN_FORMAT_ARGS(GetXLogReplayRecPtr(NULL))));
> > > > > + desc->verb,
> > > > > + desc->noun,
> > > > > + LSN_FORMAT_ARGS(currentLSN)));
> > > > > + }
> > > >
> > > >
> > > > I'm afraid this technique doesn't work, for translatability reasons.
> > > > Your whole design of having a struct with ->verb and ->noun is not
> > > > workable (which is a pity, but you can't really fight this.) You need to
> > > > spell out the whole messages for each case, something like
> > > >
> > > > if (lsntype == replay)
> > > > ereport(ERROR,
> > > > errcode(ERRCODE_QUERY_CANCELED),
> > > > errmsg("timed out while waiting for target LSN %X/%08X to be replayed; current standby_replay LSN %X/%08X",
> > > > else if (lsntype == flush)
> > > > ereport( ... )
> > > >
> > > > and so on. This means four separate messages for translation for each
> > > > message your patch is adding, which is IMO the correct approach.
> > >
> > > +1
> > > Thank you for catching this, Alvaro. Yes, I think we need to get rid
> > > of WaitLSNTypeDesc. It's nice idea, but we support too many languages
> > > to have something like this.
> > >
> >
> > Thanks for pointing this out. This approach doesn’t scale to multiple
> > languages. While switch statements are more verbose, the extra clarity
> > is justified to preserve proper internationalization. Please check the
> > updated v12.
>
> I've corrected the patchset. Mostly changed just comments, formatting
> etc. I'm going to push it if no objections.
>

Thanks for updating the patchset. LGTM.

--
Best,
Xuneng