Message-ID: <1b54a21f-5f6f-1df1-2ce6-5acc8b4bfaa5@gmail.com>
Date: Mon, 13 Feb 2023 16:07:25 +0100
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Subject: Re: Helper functions for wait_for_catchup() in Cluster.pm
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To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
References: <20230213105802.5id6zja2bmkd4czo@alvherre.pgsql>
From: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
In-Reply-To: <20230213105802.5id6zja2bmkd4czo@alvherre.pgsql>
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Hi,

On 2/13/23 11:58 AM, Alvaro Herrera wrote:
> On 2023-Jan-26, Drouvot, Bertrand wrote:
> 
>> Hi,
>>
>> On 1/26/23 10:42 AM, Alvaro Herrera wrote:
>>> On 2023-Jan-26, Drouvot, Bertrand wrote:
>>>
>>>> On 1/24/23 7:27 PM, Alvaro Herrera wrote:
>>>
>>>>> 1. I don't think wait_for_write_catchup is necessary, because
>>>>> calling wait_for_catchup() and omitting the 'mode' and 'lsn' arguments
>>>>> would already do the same thing.
>>
>> Having a closer look, it does not seem to be the case. The default mode
>> in wait_for_catchup() is 'replay' and the default mode for the lsn is 'write'.
>>
>> But in wait_for_write_catchup() we are making use of 'write' for both.
> 
> But that turns
>   $node->wait_for_catchup('foobar', 'write')
> into
>   $node->wait_for_write_catchup('foobar');
> so I don't see much value in it.

Agree.

>  Also, the patch series from which this
> patch spawned in the first place doesn't wait for write AFAICS.
> 

Right, it does wait for replay only.

> After adding some more POD docs for it, I pushed the one for replay.
> 

Thanks!

Regards,

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