Re: Mention idle_replication_slot_timeout in pg_replication_slots docs

On 2025/06/26 15:46, Nisha Moond wrote:
> On Wed, Jun 25, 2025 at 9:56 PM Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com> wrote:
>>
>> Hi,
>>
>> The pg_replication_slots documentation mentions only max_slot_wal_keep_size
>> as a condition under which the wal_status column can show unreserved or lost.
>> However, since commit ac0e33136ab, idle_replication_slot_timeout can also
>> cause this behavior when it is set. This has not been documented yet.
>> https://www.postgresql.org/docs/devel/view-pg-replication-slots.html
>>
>
> +1 to the doc update.

Thanks for the review!

>> So, how about updating the documentation to also mention
>> idle_replication_slot_timeout as a factor that can cause wal_status to
>> become unreserved or lost? Patch attached.
>>
>
> Since idle_replication_slot_timeout can only cause wal_status to
> become 'lost' and not 'unreserved', perhaps we can reword the sentence
> slightly for clarity, suggestion -
> "The last two states are seen when max_slot_wal_keep_size is
> non-negative and, the 'lost' state may also appear when
> idle_replication_slot_timeout is greater than zero."

I was thinking that when idle_replication_slot_timeout triggers,
the following functions are called, and that wal_status can become
"unreserved" before ReplicationSlotRelease() runs. It's very short
period, though. Am I wrong?

ReplicationSlotMarkDirty();
ReplicationSlotSave();
ReplicationSlotRelease();

Regards,

--
Fujii Masao
NTT DATA Japan Corporation