Message-ID: <baf01af3-5a8e-4551-88f3-ac312c490716@gmail.com>
Date: Tue, 28 Nov 2023 07:49:48 +0100
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Subject: Re: Synchronizing slots from primary to standby
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To: shveta malik <shveta.malik@gmail.com>,
 Amit Kapila <amit.kapila16@gmail.com>
Cc: "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>,
 Peter Smith <smithpb2250@gmail.com>,
 "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>,
 Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>,
 Peter Eisentraut <peter.eisentraut@enterprisedb.com>,
 Bruce Momjian <bruce@momjian.us>, Ashutosh Sharma <ashu.coek88@gmail.com>,
 Andres Freund <andres@anarazel.de>,
 pgsql-hackers <pgsql-hackers@postgresql.org>,
 Ajin Cherian <itsajin@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>
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From: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
In-Reply-To: <CAJpy0uD+yYq+2F0N8hVGSjz6YwbScFGB_fME6E831Fbg0_hkMg@mail.gmail.com>
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Hi,

On 11/28/23 4:13 AM, shveta malik wrote:
> On Mon, Nov 27, 2023 at 4:08 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>>
>> On Mon, Nov 27, 2023 at 2:27 PM Zhijie Hou (Fujitsu)
>> <houzj.fnst@fujitsu.com> wrote:
>>>
>>> Here is the updated version(v39_2) which include all the changes made in 0002.
>>> Please use for review, and sorry for the confusion.
>>>
>>
>> --- a/src/backend/replication/logical/launcher.c
>> +++ b/src/backend/replication/logical/launcher.c
>> @@ -8,20 +8,27 @@
>>    *   src/backend/replication/logical/launcher.c
>>    *
>>    * NOTES
>> - *   This module contains the logical replication worker launcher which
>> - *   uses the background worker infrastructure to start the logical
>> - *   replication workers for every enabled subscription.
>> + *   This module contains the replication worker launcher which
>> + *   uses the background worker infrastructure to:
>> + *   a) start the logical replication workers for every enabled subscription
>> + *      when not in standby_mode.
>> + *   b) start the slot sync worker for logical failover slots synchronization
>> + *      from the primary server when in standby_mode.
>>
>> I was wondering do we really need a launcher on standby to invoke
>> sync-slot worker. If so, why? I guess it may be required for previous
>> versions where we were managing work for multiple slot-sync workers
>> which is also questionable in the sense of whether launcher is the
>> right candidate for the same but now with the single slot-sync worker,
>> it doesn't seem worth having it. What do you think?
>>
>> --
> 
> Yes, earlier a manager process was needed to manage multiple slot-sync
> workers and distribute load among them, but now that does not seem
> necessary. I gave it a try (PoC) and it seems to work well.  If  there
> are no objections to this approach, I can share the patch soon.
> 

+1 on this new approach, thanks!

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com