Re: Proposal: recent access based routing for primary-replica setups

> Thank you for the kind words. We are having a great time!

Glad to hear that!

> Regarding the command knowing about the primary I think it is safe to assume.

Okay.

> We can start this way and evolve in the future if needed.

Agreed.

> I can include a note about it in the notes that the command will only receive the secondary instances as arguments.
>
> Anything else that comes to mind?

Sounds like a reasonable requirement. Also the command excludes any
instance which is in down state?

Best regards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp

> Nadav Shatz
> CTO
>
>> On Sep 16, 2025, at 7:30 PM, Tatsuo Ishii <ishii(at)postgresql(dot)org> wrote:
>>
>> 
>>>
>>> Hi Tatsuo,
>>>
>>> Sorry for the late reply - I'm traveling with my family at the moment (in
>>> Japan actually)
>>
>> Excellent! Hope you and your family are spending great time in Japan.
>>
>>> and might be delayed in responding.
>>
>> No problem at all. I think you should focus on the travel at this
>> moment.
>>
>>> Re your points:
>>> 1 - we can, but I have to say that a user I tend to prefer configuration
>>> values not have a "magic" value that does something different than the
>>> usual case like this would create. I'd stick with what we already have
>>> planned. happy to hear from others on the mailing list as well of course.
>>
>> Makes sense. I withdraw my proposal.
>>
>>> 2 - I think we can have the primary always be the first or we can
>>> completely remove it since it might be redundant as it's always going to be
>>> 0. what do you think?
>>
>> What I am not sure is, whether we can assume the command always knows
>> which host (or IP) is primary? If the answer is yes, then we could
>> omit the primary. What do you think?
>>
>>> 3 - I agree with you, next version (after we clear everything else) will
>>> have only ip/hostname+port.
>>
>> Thank you for understanding.
>>
>>> Let me know your thoughts
>>>
>>> Thanks!
>>>
>>>> On Tue, Sep 9, 2025 at 9:42 AM Tatsuo Ishii <ishii(at)postgresql(dot)org> wrote:
>>>>
>>>> Hi Nadav,
>>>>
>>>>> Hi Tatsuo,
>>>>>
>>>>> Please find attached the 3 patch files (implementation, tests, docs) with
>>>>> the updates we discussed.
>>>>>
>>>>> What do you think?
>>>>
>>>> I haven't read the code details yet but I have a few questions.
>>>>
>>>> 1) Can we use only replication_delay_source_cmd and if it's value is
>>>> 'builtin', then we treat it as replication_delay_source = builtin?
>>>> Maybe this is matter of taste but I would like to know your
>>>> opinion.
>>>>
>>>> 2) replication_delay_source_cmd will be given an ordered list of
>>>> instance identifiers. But it seems there's no way for the command
>>>> which one is the primary instance. Is it okay for the command?
>>>>
>>>> 3) Why do you have 3 kind of instance identifiers (application name,
>>>> hostname (IP) + port and node id? I thought "hostname (IP) + port"
>>>> is sufficient.
>>>>
>>>> Comments?
>>>> --
>>>> Tatsuo Ishii
>>>> SRA OSS K.K.
>>>> English: http://www.sraoss.co.jp/index_en/
>>>> Japanese:http://www.sraoss.co.jp
>>>>
>>>
>>>
>>> --
>>> Nadav Shatz
>>> Tailor Brands | CTO
>
>