Re: Implement waiting for wal lsn replay: reloaded

[Alexander Korotkov]

Hi, Xuneng!

On Fri, Jan 2, 2026 at 11:17 AM Xuneng Zhou <xunengz...@gmail.com> wrote:
> On Fri, Jan 2, 2026 at 7:42 AM Alexander Korotkov <aekorot...@gmail.com> 
> wrote:
> >
> > On Thu, Jan 1, 2026 at 7:16 PM Álvaro Herrera <alvhe...@kurilemu.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.

------
Regards,
Alexander Korotkov
Supabase

v13-0001-Extend-xlogwait-infrastructure-with-write-and-fl.patch
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v13-0004-Use-WAIT-FOR-LSN-in-PostgreSQL-Test-Cluster-wait.patch
Description: Binary data

v13-0003-Add-tab-completion-for-the-WAIT-FOR-LSN-MODE-opt.patch
Description: Binary data

v13-0002-Add-the-MODE-option-to-the-WAIT-FOR-LSN-command.patch
Description: Binary data