Re: Collation version tracking for macOS

On Mon, Nov 28, 2022 at 11:49 PM Jeff Davis <pgsql(at)j-davis(dot)com> wrote:
> Not necessarily, #2-4 (at least as implemented in v7) can only load one
> major version at a time, so can't specify minor versions:
> https://www.postgresql.org/message-id/9f8e9b5a3352478d4cf7d6c0a5dd7e82496be4b6.camel@j-davis.com
>
> With #1, you can provide control over the search order to find the
> symbol you want. Granted, if you want to specify that different
> collations look in different libraries for the same version, then it
> won't work, because the search order is global -- is that what you're
> worried about? If so, I think we need to compare it against the
> downsides of #2-4, which in my opinion are more serious.

You know more about this than I do, for sure, so don't let my vote
back the project into a bad spot. But, yeah, the thing you mention
here is what I'm worried about. Without a way to force a certain
behavior for a certain particular collation, you don't have an escape
valve if the global library ordering isn't doing what you want. Your
argument seems to at least partly be that #1 will be more usable on
the whole, and that does seem like an important consideration. People
may have a lot of collations and adjusting them all individually could
be difficult and unpleasant. However, I think it's also worth asking
what options someone has if #1 can't be made to work due to a single
ordering controlling every collation.

It's entirely possible that the scenario I'm worried about is too
remote in practice to be concerned about. I don't know how this stuff
works well enough to be certain. It's just that, on the basis of
previous experience, (1) it's not that uncommon for people to actually
end up in situations that we thought shouldn't ever happen and (2)
code that deals with collations is more untrustworthy than average.

--
Robert Haas
EDB: http://www.enterprisedb.com