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Date: Tue, 02 Apr 2024 18:21:34 +0300
From: Kartyshov Ivan <i.kartyshov@postgrespro.ru>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Andy Fan <zhihuifan1213@163.com>, Alexander Korotkov
 <aekorotkov@gmail.com>, Euler Taveira <euler@eulerto.com>, Thomas Munro
 <thomas.munro@gmail.com>, Peter Eisentraut <peter@eisentraut.org>, Amit
 Kapila <amit.kapila16@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Peter
 Smith <smithpb2250@gmail.com>, pgsql-hackers@lists.postgresql.org
Subject: Re: [HACKERS] make async slave to wait for lsn to be replayed
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On 2024-04-02 13:15, Bharath Rupireddy wrote:
> On Tue, Apr 2, 2024 at 3:41 PM Kartyshov Ivan
> <i.kartyshov@postgrespro.ru> wrote:
>> 
>> 8 years, we tried to add this feature, and now we suggest the best way
>> for this feature is to commit the minimal version first.
> 
> Just curious, do you or anyone else have an immediate use for this
> function? If yes, how are they achieving read-after-write-consistency
> on streaming standbys in their application right now without a
> function like this?

Just now, application runs pg_current_wal_lsn() after update and then
waits on loop pg_current_wal_flush_lsn() until updated.

Or use slow synchronous_commit.

-- 
Ivan Kartyshov
Postgres Professional: www.postgrespro.com