po 30. 11. 2020 v 16:06 odesílatel David G. Johnston < david.g.johns...@gmail.com> napsal:
> On Mon, Nov 30, 2020 at 12:51 AM Pavel Stehule <pavel.steh...@gmail.com> > wrote: > >> >> >> po 30. 11. 2020 v 4:24 odesílatel David G. Johnston < >> david.g.johns...@gmail.com> napsal: >> >>> On Thu, Nov 26, 2020 at 12:49 AM Pavel Stehule <pavel.steh...@gmail.com> >>> wrote: >>> >>>> >>>> >>>> čt 26. 11. 2020 v 6:41 odesílatel David G. Johnston < >>>> david.g.johns...@gmail.com> napsal: >>>> >>>>> Hackers, >>>>> >>>>> Bug # 16519 [1] is another report of confusion regarding trying to use >>>>> parameters in improper locations - specifically the SET ROLE command >>>>> within >>>>> pl/pgsql. I'm re-attaching the doc patch and am adding it to the >>>>> commitfest. >>>>> >>>> >>>> I checked this patch, and I think so it is correct - my comments are >>>> just about enhancing by some examples >>>> >>>>> >>>>> >>> Thank you for the review. >>> >>> v2 attached. >>> >>> I added examples in the two places you noted. >>> >>> Upon re-reading, I decided that opening up the section by including >>> everything then fitting in parameters with an exception for utility >>> commands (without previously/otherwise identifying them) forced some >>> undesirable verbosity. Instead, I opened up with the utility commands as >>> the main body of non-result returning commands and then moved onto >>> delete/insert/update non-returning cases when the subsequent paragraph >>> regarding parameters can then refer to the second class (by way of >>> excluding the first class). This seems to flow better, IMO. >>> >> >> I have no objections, but maybe these pages are a little bit unclear >> generally, because the core of the problem is not described. >> >> > >> Personally I miss a description of the reason why variables cannot be >> used - the description "variables cannot be used in statements without >> result" is true, but it is not core information. >> > > In the section "executing commands that don't return results" it does seem > like core information...but I get your point. > > >> The important fact is usage of an execution plan or not. >> > > This is already mentioned in the linked-to section: > > "Variable substitution currently works only in SELECT, INSERT, UPDATE, and > DELETE commands, because the main SQL engine allows query parameters only > in these commands. To use a non-constant name or value in other statement > types (generically called utility statements), you must construct the > utility statement as a string and EXECUTE it." > > I didn't feel the need to repeat that material in full in the "no results" > section. I left that pointing out the "results" dynamic there would be > useful since the original wording seemed to forget about the presence of > utility commands altogether which was confusing for that section. > ok Pavel > David J. > >
