On Thu, Jul 07, 2022 at 11:48:20AM -0400, Tom Lane wrote: > Alvaro Herrera <alvhe...@alvh.no-ip.org> writes: >> Well, this does sound unsatisfactory. I suppose one answer would be to >> load the module in all backends, in case the user wants to look at the >> value. But that would be wasteful. Maybe we should have a warning >> about it in the docs -- tell people to LOAD the library if they want to >> examine the configuration?
Yeah, for something like basic_archive, it should be fine to load it via shared_preload_libraries or LOAD as well as archive_library, but not all archive libraries might be written to handle that correctly. And this is not the most user-friendly. > The underlying issue here is that the pg_settings view doesn't show > placeholder GUCs because we lack satisfactory values to put in > most of the columns. I don't know if revisiting that conclusion > would be appropriate or not. The purist approach would be to show > NULL for any unknown column, but how many applications would that > break? And even the "known" values could change unexpectedly when > the module does get loaded, for example if the GUC has units and > the value in the config file is expressed in a non-canonical way. > (To say nothing of what a show hook might do...) Perhaps the "category" could indicate that this is a placeholder value, and the pg_settings documentation could explain exactly what that means (i.e., unknown to any libraries loaded in the current process, but may have meaning to others). -- Nathan Bossart Amazon Web Services: https://aws.amazon.com
