Thread

Re: Proposal: Conflict log history table for Logical Replication

Amit Kapila <amit.kapila16@gmail.com> — 2026-05-28T23:41:34Z

On Thu, May 21, 2026 at 9:51 PM Nisha Moond <nisha.moond412@gmail.com> wrote:
>
> On Wed, May 20, 2026 at 3:05 PM vignesh C <vignesh21@gmail.com> wrote:
> >
> > Rest of the comments were fixed.
> > The attached v37 version patch has the changes for the same. Also
> > Peter's comments on the documentation patch from [1] and Shveta's
> > comments from [2] are addressed in the attached patch.
> >
>
> Here are few comments based on v37 testing:
>
> 1) Should we consider using TOAST tables for tuple-data columns like
> remote_tuple and local_conflicts (the JSON columns)?
> This may be a corner case, but if the tuple data becomes too large to
> fit into an 8KB heap tuple, then the apply worker keeps failing while
> inserting into the CLT with errors like:
>
>   ERROR: row is too big: size 19496, maximum size 8160
>   LOG: background worker "logical replication apply worker" (PID
> 41226) exited with exit code 1
>

In the docs, it is mentioned: "column_value is the column value. The
large column values are truncated to 64 bytes." [1], so I wonder, if
we follow this why we need toast entries? Did you tried any case where
you are getting above ERROR?

> Noticed that even disable_on_error=true does not disable the
> subscription in this case.
>

Hmm, I think we need to have a documented reason if such a case
doesn't disable the subscription with the disable_on_error as true?


[1]: https://www.postgresql.org/docs/devel/logical-replication-conflicts.html

-- 
With Regards,
Amit Kapila.