Re: Collation version tracking for macOS

[Mark Dilger]

> On Jun 7, 2022, at 1:10 PM, Tom Lane <t...@sss.pgh.pa.us> wrote:
> 
> This is not the concern that I have.  I agree that if we tell a user
> that collation X changed behavior and he'd better reindex his indexes
> that use collation X, but none of them actually contain any cases that
> changed behavior, that's not a "false positive" --- that's "it's cheaper
> to reindex than to try to identify whether there's a problem".

I don't see this problem as limited to indexes, though I do understand why that 
might be the most common place for the problem to manifest itself.

As a simple example, text[] constructed using array_agg over sorted data can be 
corrupted by a collation change, and reindex won't fix it.

If we extend the table-AM interface to allow query quals to be pushed down to 
the table-AM, we might develop table-AMs that care about sort order, too.

—
Mark Dilger
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