Horton

Re: Proposal: Conflict log history table for Logical Replication

shveta malik <shveta.malik@gmail.com>

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From: shveta malik <shveta.malik@gmail.com>
To: Dilip Kumar <dilipbalaut@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, shveta malik <shveta.malik@gmail.com>
Date: 2025-12-04T06:51:20Z
Lists: pgsql-hackers

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Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Allow logical replication conflicts to be logged to a table.

  2. Avoid orphaned objects dependencies

On Wed, Dec 3, 2025 at 4:57 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> >
> > Thanks, it looks good. For the benefit of others, could you include a
> > brief note, perhaps in the commit message for now, describing how to
> > access or read this array column? We can remove it later.
>
> Thanks, okay, temporarily I have added in a commit message how we can
> fetch the data from the JSON array field.  In next version I will add
> a test to get the conflict stored in conflict log history table and
> fetch from it.
>

Thanks, I have not looked at the patch in detail yet, but a few things:

1)
Assert is hit here:
 LOG:  logical replication apply worker for subscription "sub1" has started
TRAP: failed Assert("slot != NULL"), File: "conflict.c", Line: 669, PID: 137604

Steps: create table tab1 (i int primary key, j int);
Pub: insert into tab1 values(10,10); insert into tab1 values(20,10);
Sub:  delete from tab1 where i=10;
Pub:  delete from tab1 where i=10;

2)
I see that key_tuple still points to RI and there is no RI field
added. It seems that discussion at [1] is missed in this patch.

[1]: https://www.postgresql.org/message-id/CAA4eK1L3umixUUik7Ef1eU%3Dx-JMb8iXD7rWWExBMP4dmOGTS9A%40mail.gmail.com

thanks
Shveta