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

Hi Nadav,

Thank you for updating the patch. I will look into that.

I have a question. Have you actually tried the patch with AWS Aurora?
I am wondering how patched pgpool works with Aurora. I am asking
because in the doc "8.5. Aurora Configuration Example":

Set sr_check_period to 0 to disable streaming replication delay
checking. This is because Aurora does not provide necessary functions
to check the replication delay.

sr_check_period = 0

So streaming replication checking is disabled, and it means that your
patch is also effectively disabled too.

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

> Hi Tatsuo,
>
> Thank you for the notes - please find attached an updated version.
>
> What do you think?
>
> Thanks,
>
> On Mon, Aug 25, 2025 at 5:18 AM Tatsuo Ishii <ishii(at)postgresql(dot)org> wrote:
>
>> Hi Nadav,
>>
>> Thank you for the patch!
>>
>> I have one question. How do you provide a password (sr_check_password)
>> while executing replication_delay_source_cmd as sr_check_user? In my
>> understanding replication_delay_source_cmd is executed through su
>> command in your patch. In this case su command tries to read the
>> password from terminal. I don't see such a code in the patch.
>>
>> BTW, I start to think that executing replication_delay_source_cmd as
>> sr_check_user might not be a good idea. sr_check_user is a database
>> user, not OS user. In PostgreSQL they are not necessarily the
>> same. Also doing su in pgpool process needs to be very carefully to
>> avoid vulnerability. Probably we just execute it as pgpool OS user?
>>
>> Lastly when I apply the patches using git apply, there are some
>> trailing space errors.
>>
>> $ git apply ~/external-lag-feature-implementation.patch
>> /home/t-ishii/external-lag-feature-implementation.patch:314: trailing
>> whitespace.
>>
>> /home/t-ishii/external-lag-feature-implementation.patch:317: trailing
>> whitespace.
>>
>> /home/t-ishii/external-lag-feature-implementation.patch:318: trailing
>> whitespace.
>> cmd_len = strlen(escaped_cmd) +
>> /home/t-ishii/external-lag-feature-implementation.patch:320: trailing
>> whitespace.
>>
>> /home/t-ishii/external-lag-feature-implementation.patch:322: trailing
>> whitespace.
>> snprintf(full_command, cmd_len, "su - %s -c '%s'",
>> warning: squelched 4 whitespace errors
>> warning: 9 lines add whitespace errors.
>>
>> $ git apply ~/external-lag-feature-tests.patch
>> /home/t-ishii/external-lag-feature-tests.patch:87: trailing whitespace.
>> - test_parsing.sh: Unit test for parsing logic
>> /home/t-ishii/external-lag-feature-tests.patch:440: trailing whitespace.
>> # Test 2: Float values
>> warning: 2 lines add whitespace errors.
>>
>> Also I have some compilation errors after patching the source
>> code. See attached compilation log.
>>
>> Best regards,
>> --
>> 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