Date: Tue, 29 Nov 2022 11:29:13 -0500
From: Bruce Momjian <bruce@momjian.us>
To: SATYANARAYANA NARLAPURAM <satyanarlapuram@gmail.com>
Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>,
	Andrey Borodin <amborodin86@gmail.com>,
	Kyotaro Horiguchi <horikyota.ntt@gmail.com>,
	Laurenz Albe <laurenz.albe@cybertec.at>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: An attempt to avoid
 locally-committed-but-not-replicated-to-standby-transactions in synchronous
 replication
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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?

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

Embrace your flaws.  They make you human, rather than perfect,
which you will never be.