On Sat, Jun 15, 2019 at 02:11:41PM -0700, Peter Geoghegan wrote:
> On Sat, Jun 15, 2019 at 1:39 PM Noah Misch <noah@leadboat.com> wrote:
> > To me, this text implies a cautious DBA should amcheck every index. Reading
> > the thread[1], I no longer think that. It's enough to monitor that VACUUM
> > doesn't start failing persistently on any index. I suggest replacing this
> > release note text with something like the following:
> >
> > Avoid writing erroneous btree index data that does not change query results
> > but causes VACUUM to abort with "failed to re-find parent key". Affected
> > indexes are rare; REINDEX fixes them.
> >
> > (I removed "key truncation during a page split" as being too technical for
> > release notes.)
>
> I agree that this isn't terribly significant in general. Your proposed
> wording seems better than what we have now, but a reference to INCLUDE
> indexes also seems like a good idea. They are the only type of index
> that could possibly have the issue with page deletion/VACUUM becoming
> confused.
If true, that's important to mention, yes.