Greetings, * Bruce Momjian (br...@momjian.us) wrote: > On Mon, Jan 13, 2020 at 01:56:30PM -0500, Stephen Frost wrote: > > > I think that having ALTER SYSTEM commands in pg_dumpall output > > > would be a problem. It would cause all kinds of problems whenever > > > parameters change. Thinking of the transition "checkpoint_segments" > > > -> "max_wal_size", you'd have to build some translation magic into > > > pg_dump. > > > Besides, such a feature would make it harder to restore a dump taken > > > with version x into version x + n for n > 0. > > > > pg_dump already specifically has understanding of how to deal with old > > options in other things when constructing a dump for a given version- > > and we already have issues that a dump taken with pg_dump X has a good > > chance of now being able to be restoreding into a PG X+1, that's why > > it's recommended to use the pg_dump for the version of PG you're > > intending to restore into, so I don't particularly agree with any of the > > arguments presented above. > > One issue is that system table GUC settings (e.g., per-database, > per-user) cannot include postgresql.conf-only settings, like > max_wal_size, so system tables GUC settings are less likely to be > renamed than postgresql.conf.auto settings. FYI, we are more inclined > to allow postgresql.conf-only changes than others because there is less > impact on applications.
I'm a bit unclear about what's being suggested here. When you are talking about 'applications', are you referring specifically to pg_dump and pg_restore, or are you talking about regular user applications? If you're referring to pg_dump/restore, then what I'm understanding from your comments is that if we made pg_dump/restore aware of ALTER SYSTEM and were made to support it that we would then be less inclined to change the names of postgresql.conf-only settings because, if we do so, we have to update pg_dump/restore. I can see some argument in that direction but my initial reaction is that I don't feel like the bar would really be moved very far, and, if we came up with some mapping from one to the other for those, I actually think it'd be really helpful downstream for packagers and such who routinely are dealing with updating from an older postgresql.conf file to a newer one when an upgrade is done. Thanks, Stephen
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