Re: Implement waiting for wal lsn replay: reloaded

Hi,

On Fri, Sep 26, 2025 at 7:22 PM Xuneng Zhou <xunengzhou(at)gmail(dot)com> wrote:
>
> Hi Álvaro,
>
> Thanks for your review.
>
> On Tue, Sep 16, 2025 at 4:24 AM Álvaro Herrera <alvherre(at)kurilemu(dot)de> wrote:
> >
> > On 2025-Sep-15, Alexander Korotkov wrote:
> >
> > > > It's LGTM. The same pattern is observed in VACUUM, EXPLAIN, and CREATE
> > > > PUBLICATION - all use minimal grammar rules that produce generic
> > > > option lists, with the actual interpretation done in their respective
> > > > implementation files. The moderate complexity in wait.c seems
> > > > acceptable.
> >
> > Actually I find the code in ExecWaitStmt pretty unusual. We tend to use
> > lists of DefElem (a name optionally followed by a value) instead of
> > individual scattered elements that must later be matched up. Why not
> > use utility_option_list instead and then loop on the list of DefElems?
> > It'd be a lot simpler.
>
> I took a look at commands like VACUUM and EXPLAIN and they do follow
> this pattern. v11 will make use of utility_option_list.
>
> > Also, we've found that failing to surround the options by parens leads
> > to pain down the road, so maybe add that. Given that the LSN seems to
> > be mandatory, maybe make it something like
> >
> > WAIT FOR LSN 'xy/zzy' [ WITH ( utility_option_list ) ]
> >
> > This requires that you make LSN a keyword, albeit unreserved. Or you
> > could make it
> > WAIT FOR Ident [the rest]
> > and then ensure in C that the identifier matches the word LSN, such as
> > we do for "permissive" and "restrictive" in
> > RowSecurityDefaultPermissive.
>
> Shall make LSN an unreserved keyword as well.

Here's the updated v11. Many thanks Jian for off-list discussions and review.

Best,
Xuneng