Re: "out of relcache_callback_list slots" after multiple calls to pg_logical_slot_get_binary_changes

On Wed, Feb 22, 2023 at 12:03 PM Kyotaro Horiguchi
<horikyota(dot)ntt(at)gmail(dot)com> wrote:
>
> At Tue, 21 Feb 2023 10:31:29 +0000, "shiy(dot)fnst(at)fujitsu(dot)com" <shiy(dot)fnst(at)fujitsu(dot)com> wrote in
> > Thanks for your reply. I agree that's expensive. Attach a new patch which adds a
> > static boolean to avoid duplicate registration.
>
> Thank you for the patch. It is exactly what I had in my mind. But now
> that I've had a chance to mull it over, I came to think it might be
> better to register the callbacks at one place. I'm thinking we could
> create a new function called register_callbacks() or something and
> move all the calls to CacheRegisterSyscacheCallback() into that. What
> do you think about that refactoring?
>
> I guess you could say that that refactoring somewhat weakens the
> connection or dependency between init_rel_sync_cache and
> rel_sync_cache_relation_cb, but anyway the callback works even if
> RelationSyncCache is not around.
>

If you are going to do that, then won't just copying the
CacheRegisterSyscacheCallback(PUBLICATIONOID... into function
init_rel_sync_cache() be effectively the same as doing that?

Then almost nothing else to do...e.g. no need for a new extra static
boolean if static RelationSyncCache is acting as the one-time guard
anyway.

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Kind Regards,
Peter Smith.
Fujitsu Australia