Re: Replication failure, slave requesting old segments - Mailing list pgsql-general

From Stephen Frost
Subject Re: Replication failure, slave requesting old segments
Date
Msg-id 20180813120437.GZ3326@tamriel.snowman.net
Whole thread Raw
In response to Re: Replication failure, slave requesting old segments  (Adrian Klaver <adrian.klaver@aklaver.com>)
List pgsql-general
Greetings,

* Adrian Klaver (adrian.klaver@aklaver.com) wrote:
> On 08/12/2018 03:54 PM, Stephen Frost wrote:
> >* Phil Endecott (spam_from_pgsql_lists@chezphil.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

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