Re: An attempt to avoid locally-committed-but-not-replicated-to-standby-transactions in synchronous replication

On Tue, Nov 29, 2022 at 8:29 AM Bruce Momjian <bruce(at)momjian(dot)us> wrote:

> On Tue, Nov 29, 2022 at 08:14:10AM -0800, SATYANARAYANA NARLAPURAM wrote:
> > 2. Process proc die immediately when a backend is waiting for sync
> > replication acknowledgement, as it does today, however, upon restart,
> > don't open up for business (don't accept ready-only connections)
> > unless the sync standbys have caught up.
> >
> >
> > Are you planning to block connections or queries to the database? It
> would be
> > good to allow connections and let them query the monitoring views but
> block the
> > queries until sync standby have caught up. Otherwise, this leaves a
> monitoring
> > hole. In cloud, I presume superusers are allowed to connect and monitor
> (end
> > customers are not the role members and can't query the data). The same
> can't be
> > true for all the installations. Could you please add more details on your
> > approach?
>
> I think ALTER SYSTEM should be allowed, particularly so you can modify
> synchronous_standby_names, no?

Yes, Change in synchronous_standby_names is expected in this situation.
IMHO, blocking all the connections is not a recommended approach.

>
> --
> Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
> EDB https://enterprisedb.com
>
> Embrace your flaws. They make you human, rather than perfect,
> which you will never be.
>