Hi, Thank you for the grammar review and the clear recommendation.
On Wed, Oct 15, 2025 at 4:51 PM Álvaro Herrera <[email protected]> wrote: > > I didn't review the patch other than look at the grammar, but I disagree > with using opt_with in it. I think WITH should be a mandatory word, or > just not be there at all. The current formulation lets you do one of: > > 1. WAIT FOR LSN '123/456' WITH (opt = val); > 2. WAIT FOR LSN '123/456' (opt = val); > 3. WAIT FOR LSN '123/456'; > > and I don't see why you need two ways to specify an option list. I agree with this as unnecessary choices are confusing. > > So one option is to remove opt_wait_with_clause and just use > opt_utility_option_list, which would remove the WITH keyword from there > (ie. only keep 2 and 3 from the above list). But I think that's worse: > just look at the REPACK grammar[1], where we have to have additional > productions for the optional parenthesized option list. > > > > So why not do just > > +opt_wait_with_clause: > + WITH '(' utility_option_list ')' { $$ = $3; } > + | /*EMPTY*/ { $$ = NIL; } > + ; > > which keeps options 1 and 3 of the list above. Your suggested approach of making WITH mandatory when options are present looks better. I've implemented the change as you recommended. Please see patch 3 in v16. > > > > Note: you don't need to worry about WITH_LA, because that's only going > to show up when the user writes WITH TIME or WITH ORDINALITY (see > parser.c), and that's a syntax error anyway. > Yeah, we require '(' immediately after WITH in our grammar, the lookahead mechanism will keep it as regular WITH, and any attempt to write "WITH TIME" or "WITH ORDINALITY" would be a syntax error anyway, which is expected. Best, Xuneng
v16-0001-Add-pairingheap_initialize-for-shared-memory-usag copy.patch
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v16-0003-Implement-WAIT-FOR-command.patch
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v16-0002-Add-infrastructure-for-efficient-LSN-waiting.patch
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