Date: Tue, 4 Jun 2019 15:58:53 +0000
From: Andres Freund <andres@anarazel.de>
To: Amit Khandekar <amitdkhan.pg@gmail.com>
Cc: tushar <tushar.ahuja@enterprisedb.com>,
	Petr Jelinek <petr.jelinek@2ndquadrant.com>,
	Robert Haas <robertmhaas@gmail.com>,
	Craig Ringer <craig@2ndquadrant.com>,
	Petr Jelinek <petr@2ndquadrant.com>,
	pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Minimal logical decoding on standbys
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Hi,

On 2019-06-04 15:51:01 +0530, Amit Khandekar wrote:
> After giving more thought on this, I think it might make sense to
> arrange for the xl_running_xact record to be sent from master to the
> standby, when a logical slot is to be created on standby. How about
> standby sending a new message type to the master, requesting for
> xl_running_xact record ? Then on master, ProcessStandbyMessage() will
> process this new message type and call LogStandbySnapshot().

I think that should be a secondary feature. You don't necessarily know
the upstream master, as the setup could be cascading one. I think for
now just having to wait, perhaps with a comment to manually start a
checkpoint, ought to suffice?

Greetings,

Andres Freund