Horton

Re: Add two missing tests in 035_standby_logical_decoding.pl

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

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From: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: vignesh C <vignesh21@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-04-25T07:25:39Z
Lists: pgsql-hackers 
Hi,

On 4/25/23 6:43 AM, Amit Kapila wrote:
> On Mon, Apr 24, 2023 at 5:38 PM Drouvot, Bertrand
> <bertranddrouvot.pg@gmail.com> wrote:
>>
>> We are waiting here at a maximum for 10 * $default_timeout (means 3 minutes) before
>> we time out. Would you prefer to wait more than 3 minutes at a maximum?
>>
> 
> No, because I don't know what would be a suitable timeout here.

Yeah, I understand that. On the other hand, there is other places that
rely on a timeout, for example:

- wait_for_catchup(), wait_for_slot_catchup(),
wait_for_subscription_sync() by making use of poll_query_until.
- wait_for_log() by setting a max_attempts.

Couldn't we have the same concern for those ones? (aka be suitable on
slower machines).

> At
> this stage, I don't have a good idea on how to implement this test in
> a better way. Can we split this into a separate patch as the first
> test is a bit straightforward, we can push that one and then
> brainstorm on if there is a better way to test this functionality.
> 

I created a dedicated v4-0002-Add-retained-WAL-test-in-035_standby_logical_deco.patch
just shared up-thread.

Regards,

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

Commits

  1. Fix the race condition in the test case added by commit a6e04b1d20.

  2. Test that invalidated logical slots doesn't retain WAL.

  3. Add a test to verify that subscription to the standby works.

  4. Reduce the log level in 035_standby_logical_decoding.pl.