Re: pgoutput: schema cache cleanup after streamed 2PC

Hi,

On Thu, 17 Sept 2026 at 18:22, Hayato Kuroda (Fujitsu)
<kuroda(dot)hayato(at)fujitsu(dot)com> wrote:
> Thanks for the quick update. Let me dump my thought in [1] just in case.
> Some tests may be needed (no need to include in core though).

I used a separate publisher/subscriber test covering both commit and
rollback. It confirmed that the cache usage stays flat with the cleanup,
I too dont think this explicitly warrants a core test.

> > I've moved cleanup_rel_sync_cache(txn->xid, true) to
> > pgoutput_stream_prepare_txn() in v2 and updated the comments.
>
> I think the second argument should be renamed. Do you have anything in your mind?
> My idea: mark_schema_sent.

Thanks for the suggestion. I initially thought of set_schema_sent, but
mark_schema_sent sounds better. I've used that in v3 and updated the nearby
comments.

> [1]:
> IIUC pgoutput_commit_prepared_txn() and pgoutput_rollback_prepared_txn() are used
> for both streamed and non-streamed cases. So putting the cleanup for streamed
> transactions should be in pgoutput_stream_prepare_txn() as much as possible.
>
> The main question here is whether we pass true or false for is_commit. I think
> true can be used, because no need to re-send RELATION messages once it's handled
> by the subscriber side.
>
> For streaming = on case, an apply worker firstly serialize streamed changes, then
> it applies them when STREAM COMMIT or STREAM PREPARE are received. It means
> RELATION messages have already handled in PREPARE phase.
>
> For streaming = parallel case, both leader and parallel apply worker handle
> RELATION messages immediately.

Thanks for the analysis.

Attached v3 with changes.

Regards,
Ayush