Re: Clarification on the release notes of postgresql 12 regarding pg_upgrade

On Fri, Oct 4, 2019 at 9:09 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > You can't REINDEX safely regarding that note.
>
> Actually running into that problem is quite unlikely; and if you did
> hit it, it'd just mean that the REINDEX fails, not that you have any
> urgent problem to fix.  I'd encourage you to just go ahead and REINDEX,
> if you have indexes that could benefit from the other changes.

Right. It is hard to imagine an application that evolved to fully rely
on the previous slightly higher limit, and cannot tolerate a reduction
in the limit by only 8 bytes. The limit applies to a tuple *after*
TOAST compression has been applied.

-- 
Peter Geoghegan