Re: Replication failure, slave requesting old segments

Greetings,

* Adrian Klaver (adrian(dot)klaver(at)aklaver(dot)com) wrote:
> On 08/12/2018 03:54 PM, Stephen Frost wrote:
> >* Phil Endecott (spam_from_pgsql_lists(at)chezphil(dot)org) wrote:
> >>OK. I think this is perhaps a documentation bug, maybe a missing
> >>warning when the master reads its configuration, and maybe (as you say)
> >>a bad default value.
> >
> >If we consider it to be an issue worthy of a change then we should
> >probably just change the default value, and maybe not even allow it to
> >be set lower than '1'.
>
> I would say leave the default at 0 as it leaves no doubt that you are
> performing without a net. A setting of '1' implies you are covered and for a
> fast moving cluster or slow moving one with sufficient downtime that would
> not be the case. Better to let the end user know this is not a simple
> problem and some thought needs to go into configuration.

Uh, this specific case is where there *is* a 'safety net' though-
archive command and restore command were configured and being used, so I
don't buy off on this argument at all.

Maybe we just internally bump wal_keep_segments to '1' to avoid this
specific risk without actually changing the default or making people
change their existing configurations, but if this is really what's
happening then I don't think the answer is "don't do anything."

Thanks!

Stephen