Re: BUG #17212: pg_amcheck fails on checking temporary relations

> On Oct 11, 2021, at 2:33 PM, Peter Geoghegan <pg@bowt.ie> wrote:
> 
> On Mon, Oct 11, 2021 at 1:20 PM Mark Dilger
> <mark.dilger@enterprisedb.com> wrote:
>> Ok, I went with this suggestion, and also your earlier suggestion to have a <warning> in the pg_amcheck docs about using --parent-check and/or --rootdescend against servers in recovery.
> 
> My concern with --parent-check (and with --rootdescend) had little to
> do with Hot Standby. I suggested using a warning because these options
> alone can pretty much cause bedlam on a production database.

Ok, that makes more sense.  Would you care to rephrase them?  I don't think we need another round of patches posted.

> At least
> if they're used carelessly. Again, bt_index_parent_check()'s relation
> level locks will block all DML, as well as VACUUM. That isn't the case
> with any of the other pg_amcheck options, including those that call
> bt_index_check(), and including the heapam verification functionality.
> 
> It's also true that --parent-check won't work in Hot Standby mode, of
> course. So it couldn't hurt to mention that in passing, at the same
> point. But that's a secondary point, at best. We don't need to use a
> warning box because of that.
> 
> Overall, your approach looks good to me. Will Robert take care of
> committing this, or should I?

I'd appreciate if you could fix up the <warning> in the docs and do the commit.

Thanks!

—
Mark Dilger
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