Re: Proposal: Conflict log history table for Logical Replication

On Wed, Nov 4, 2026 at 9:29 PM Zhijie Hou <houzhijie22(at)gmail(dot)com> wrote:
>
> Hi,
>
> On Wed, Nov 4, 2026 at 03:08 PM Peter Smith wrote:
> >
> > I think the GUC timezone is yet another setting that can affect how a
> > key value is written, so it should be similary mentioned.
>
> I confirmed that you are right, changing the subscriber's timezone
> setting changes the UTC offset in the recorded string:
>
> -- Conflict 1 recorded with timezone = 'UTC',
> -- Conflict 2 recorded with timezone = 'Asia/Tokyo' on the same key:
>
> SELECT replica_identity,
> replica_identity->>'ts' = '2025-01-01 00:00:00+00' AS text_match,
> (replica_identity->>'ts')::timestamptz = '2025-01-01
> 00:00:00+00' AS cast_match
> FROM pg_conflict.pg_conflict_log_16390;
>
> replica_identity | text_match | cast_match
> ---------------------------------+------------+------------
> {"ts":"2025-01-01 00:00:00+00"} | t | t
> {"ts":"2025-01-01 09:00:00+09"} | f | t
>
> I have added timezone to the list in this version.
>

I found one more setting that can affect how a key is written: lc_monetary.

It's probably unlikely, and I can only cause the CLT issue when
binary=true (otherwise the text money value is replicated and a money
conversion ERROR happens instead of a CLT conflict). OTOH, it was
still possible to cause different values, putting lc_monetary in the
same category as other settings that are already documented.

e.g.
-- Conflict 1 recorded with lc_monetary = 'C',
-- Conflict 2 recorded with lc_monetary = 'en_GB.UTF-8', on the same key:

test_sub=# select * from pg_conflict.pg_conflict_log_16486;
relid | schemaname | relname | conflict_type | remote_xid |
remote_commit_lsn | remote_commit_ts | apply_orig
in | replica_identity_full | replica_identity | local_conflicts |
has_omitted_values
-------+------------+---------+----------------+------------+-------------------+-------------------------------+-----------
---+-----------------------+----------------------+-----------------+--------------------
16458 | public | t | delete_missing | 729 |
0/01C7DA18 | 2026-11-04 17:10:35.416412-05 | pg_16486
| f | {"amount":"$123.45"} | | f
16458 | public | t | delete_missing | 731 |
0/01C7DBB8 | 2026-11-04 17:11:59.635981-05 | pg_16486
| f | {"amount":"£123.45"} | | f
(2 rows)

======
Kind Regards,
Peter Smith.
Fujitsu Australia