Horton

RE: issue with synchronized_standby_slots

Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>

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From: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>
To: 'Shlok Kyal' <shlok.kyal.oss@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>
Cc: Fabrice Chapuis <fabrice636861@gmail.com>, Ashutosh Sharma <ashu.coek88@gmail.com>, Rahila Syed <rahilasyed90@gmail.com>, Alexander Kukushkin <cyberdemn@gmail.com>, "Zhijie Hou (Fujitsu)" <houzj.fnst@fujitsu.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-10-24T07:54:30Z
Lists: pgsql-hackers 
Dear Shlok,

```
-- Can set synchronized_standby_slots to a non-existent slot name.
ALTER SYSTEM SET synchronized_standby_slots='missing';
SELECT pg_reload_conf();

-- Reset the GUC.
ALTER SYSTEM RESET synchronized_standby_slots;
SELECT pg_reload_conf();
```

pg_reload_conf() is called twice here but I'm not sure it is really needed.
ALTER SYSTEM itself can validate parameters via parse_and_validate_value(elevel=ERROR),
and pg_reload_conf() won't affect synchronously. Also, the backend won't output
even if the parameter is invalid.

Best regards,
Hayato Kuroda
FUJITSU LIMITED