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Re: How should pg_standby get over the gap of timeline? - Mailing list pgsql-hackers

From Pavan Deolasee
Subject Re: How should pg_standby get over the gap of timeline?
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Msg-id 2e78013d0811200715q36ab6ab5x8ec03fa2d712157c@mail.gmail.com
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In response to Re: How should pg_standby get over the gap of timeline?  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
Responses Re: How should pg_standby get over the gap of timeline?
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On Thu, Nov 20, 2008 at 8:36 PM, Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> wrote:

That seems like a dangerous assumption. What if the standby had fallen behind before the failover? It's not safe to failover back to the original primary in that case. We'd need some kind of safeguards against that.



For synchronous replication, what if we ensure that the standby has received the WAL (atleast in its buffers) before writing it to disk on the primary ? If we do that, I think the old standby can never fall behind the primary and it would be easy for the old primary to join back the replication without a fresh backup.

Of course, this doesn't work for async replication.

Thanks,
Pavan

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Pavan Deolasee
EnterpriseDB     http://www.enterprisedb.com

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