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

On Wed, Aug 27, 2025 at 9:09 AM Hayato Kuroda (Fujitsu)
<kuroda(dot)hayato(at)fujitsu(dot)com> wrote:
>
> Dear Thadeus,
>
> > I do not know or understand what a "spill" is.
>
> As I wrote in a previous mail, logical decoding (and logical replication)
> sometimes writes changes into the disk to avoid using too-much memory, and the
> ".spill" file is the fragment. This can happen when the total amount of decoded
> changes exceeds logical_decoding_work_mem.
>
> > I will look it up. But the tables that are part of the
> > publication are not updated as part of any huge transaction. They may be part of some other
> > long running procedures
>
> Actually, logical decoding decodes all changes even if tables are not published,
> and suppress outputting changes at commit phase.
>

One can avoid the generation of so many spill files for large
transactions by using streaming=on or streaming=parallel while
creating subscriptions.

--
With Regards,
Amit Kapila.