Re: [CAUTION: SUSPECT SENDER] RE: [CAUTION: SUSPECT SENDER] RE: [CAUTION: SUSPECT SENDER] RE: BUG #19029: Replication Slot size keeps increasing while logical subscription works fine

Thank you Hayato.

I will check this out today. I'm glad this isn't a bug, but an issue that I
can address myself. We can't afford to put the brakes on logical
replication for another three months.

Thadeus Anand.

On Wed, 27 Aug, 2025, 9:02 am Hayato Kuroda (Fujitsu), <
kuroda(dot)hayato(at)fujitsu(dot)com> wrote:

> Dear Thadeus,
>
> Thanks for sharing the info. From your screenshot, I can see that there is
> a
> transaction 10861356 which modifies many tuples. Logical decoding has a
> mechanism
> to spill a part of changes to the disk to avoid using much amount of
> memory and
> it seems to be used here.
>
> I think as next step we can clarify which process starts the transaction.
> Can
> you run below query when you reproduce the issue?
>
> ```
> # SELECT * FROM pg_stat_activity WHERE backend_xid = '${XID}';
> ```
>
> Files under pg_replslot/${slot_name} has a format:
> `xid-${XID}-lsn-${LSN_UPPER}-${LSN_LOWER}.spill`
> so that ${XID} can be tuned when it happns. In your attached case,
> 10861356.
>
> Best regards,
> Hayato Kuroda
> FUJITSU LIMITED
>
>