| From: | Shlok Kyal <shlok(dot)kyal(dot)oss(at)gmail(dot)com> |
|---|---|
| To: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> |
| Cc: | vignesh C <vignesh21(at)gmail(dot)com>, Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>, shveta malik <shveta(dot)malik(at)gmail(dot)com>, Shinya Kato <shinya11(dot)kato(at)gmail(dot)com>, Peter Smith <smithpb2250(at)gmail(dot)com>, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, "Hayato Kuroda (Fujitsu)" <kuroda(dot)hayato(at)fujitsu(dot)com>, "Zhijie Hou (Fujitsu)" <houzj(dot)fnst(at)fujitsu(dot)com>, Dilip Kumar <dilipbalaut(at)gmail(dot)com>, Nisha Moond <nisha(dot)moond412(at)gmail(dot)com>, Peter Eisentraut <peter(at)eisentraut(dot)org>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Euler Taveira <euler(at)eulerto(dot)com>, Michael Paquier <michael(at)paquier(dot)xyz>, "Jonathan S(dot) Katz" <jkatz(at)postgresql(dot)org> |
| Subject: | Re: Logical Replication of sequences |
| Date: | 2025-12-24 06:45:19 |
| Message-ID: | CANhcyEUkV-T6cK142w9wfME9nobFHOvn1f4itJLMG-oR4QoPbQ@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Mon, 22 Dec 2025 at 11:08, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Thu, Dec 18, 2025 at 12:37 PM Shlok Kyal <shlok(dot)kyal(dot)oss(at)gmail(dot)com> wrote:
> >
> > While working on another thread, I noticed a bug introduced by commit
> > as part of this thread.
> > In function pg_get_publication_tables, We have code:
> > ```
> > if (pub_elem->alltables)
> > pub_elem_tables = GetAllPublicationRelations(RELKIND_RELATION,
> > pub_elem->pubviaroot);
> > else
> > {
> > List *relids,
> > *schemarelids;
> >
> > relids = GetPublicationRelations(pub_elem->oid,
> > pub_elem->pubviaroot ?
> > PUBLICATION_PART_ROOT :
> > PUBLICATION_PART_LEAF);
> > schemarelids = GetAllSchemaPublicationRelations(pub_elem->oid,
> > pub_elem->pubviaroot ?
> > PUBLICATION_PART_ROOT :
> > PUBLICATION_PART_LEAF);
> > pub_elem_tables = list_concat_unique_oid(relids, schemarelids);
> > }
> > ```
> >
> > So, when we create an 'ALL SEQUENCE publication' and we execute
> > 'SELECT * from pg_publication_tables'
> > We will enter the else condition in the above code, which does not
> > seem correct to me.
> > It will call functions which are not required to be called. It will
> > also call the function 'GetPublicationRelations' which contradicts the
> > comment above this function.
> >
>
> I see that we will needlessly call GetPublicationRelations or others
> for all_schema publication but is there any problem/bug due to that?
No, I did not encounter a problem/bug.
> AFAICS, the function will still return correct results. Yes, there is
> an argument to better performance for large numbers of all_sequence
> publications and that too in DDL like Create/Alter Subscription. I am
> not sure that it is really worth adding more checks at multiple places
> in the code though we can improve comments atop
> GetPublicationRelations. I feel if we encounter such cases in the
> field then it makes sense to add these additional optimizations at
> various places.
>
I agree with you. And attached a patch to modify the comment above
GetPublicationRelations.
Thanks,
Shlok Kyal
| Attachment | Content-Type | Size |
|---|---|---|
| v1-0001-Improve-comment-for-GetPublicationRelations.patch | application/octet-stream | 1.4 KB |
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