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

Hi,

Thank you everyone for your wonderful guidance. Really appreciate it.

I have a couple of doubts.

Can these spill files in the pg_replslot folder be deleted safely, if all
the subscribers have caught up? (I noticed last night when I restarted my
publisher, the spill files were removed automatically)

Can I use ALTER SUBSCRIPTION to set streaming on, with my existing
subscriptions?

Thadeus.




On Wed, Aug 27, 2025 at 10:06 AM Amit Kapila <amit.kapila16@gmail.com>
wrote:

> On Wed, Aug 27, 2025 at 9:09 AM Hayato Kuroda (Fujitsu)
> <kuroda.hayato@fujitsu.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.
>