Обсуждение: pg_dumpall renders ALTER TABLE for a view?
Hello,
We found the root cause for an issue we encountered restoring a saved database stored with pg_dumpall, but during this investigation we realized that pg_dump/all renders `ALTER TABLE` statements for views, for example to convey ownership.
I get that this is synonymous in most cases, except when there is an event trigger for `ALTER TABLE`, it ends up firing the event trigger for the views, and any event triggers expected to fire on `ALTER VIEW` statements do not fire.
Is this something we can contribute a fix for, or is this some kind of necessary b/w compat issue that must remain? Looking at the history of ALTER VIEW it looks like it has existed since at least 9.0, so it seems safe to me from a b/w compat standpoint to render the correct statement.
Thanks!
-Michel
Michel Pelletier <pelletier.michel@gmail.com> writes:
> We found the root cause for an issue we encountered restoring a saved
> database stored with pg_dumpall, but during this investigation we realized
> that pg_dump/all renders `ALTER TABLE` statements for views, for example to
> convey ownership.
> I get that this is synonymous in most cases, except when there is an event
> trigger for `ALTER TABLE`, it ends up firing the event trigger for the
> views, and any event triggers expected to fire on `ALTER VIEW` statements
> do not fire.
> Is this something we can contribute a fix for, or is this some kind of
> necessary b/w compat issue that must remain?
We're not likely to change the fact that you're allowed to write ALTER
TABLE for this, so if your event triggers get broken by doing that
you'd best fix the event triggers.
I don't have any great objection to making pg_dump emit the more modern
spelling (I think ... you'd need to look into pg_restore to make sure
it's not assuming something in this area). But doing that won't
really remove the hazard.
regards, tom lane
On Thu, Dec 15, 2022 at 9:15 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Michel Pelletier <pelletier.michel@gmail.com> writes:
> I get that this is synonymous in most cases, except when there is an event
> trigger for `ALTER TABLE`, it ends up firing the event trigger for the
> views, and any event triggers expected to fire on `ALTER VIEW` statements
> do not fire.
> Is this something we can contribute a fix for, or is this some kind of
> necessary b/w compat issue that must remain?
We're not likely to change the fact that you're allowed to write ALTER
TABLE for this, so if your event triggers get broken by doing that
you'd best fix the event triggers.
For sure, and we're working on fixing the triggers, I should have been more clear that I'm not suggesting any changes to the server behavior, just to the dump/restore process.
I don't have any great objection to making pg_dump emit the more modern
spelling (I think ... you'd need to look into pg_restore to make sure
it's not assuming something in this area). But doing that won't
really remove the hazard.
Agree it won't remove the hazard, but should reduce the kind of collateral damage we encountered. Will examine pg_restore as you suggested to scope the work better.
Thank you!
-Michel