Re: REINDEX backend filtering

> On Mar 15, 2021, at 11:32 AM, Mark Dilger <mark(dot)dilger(at)enterprisedb(dot)com> wrote:
>
> If you had a real, not fake, collation provider which actually provided a collation with an actual version number, stopped the server, changed the behavior of the collation as well as its version number, started the server, and ran REINDEX (OUTDATED), I think that would be a more real-world test. I'm not demanding that you write such a test. I'm just saying that it is strange that we don't have coverage for this anywhere, and was asking if you think there is such coverage, because, you know, maybe I just didn't see where that test was lurking.

I should add some context regarding why I mentioned this issue at all.

Not long ago, if an upgrade of icu or libc broke your collations, you were sad. But postgres didn't claim to be competent to deal with this problem, so it was just a missing feature. Now, with REINDEX (OUTDATED), we're really implying, if not outright saying, that postgres knows how to deal with collation upgrades. I feel uncomfortable that v14 will make such a claim with not a single regression test confirming such a claim. I'm happy to discover that such a test is lurking somewhere and I just didn't see it.

—
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company