Commits on Dec 11, 2025

1. Add configurable conflict log table for Logical Replication …

   This patch adds a feature to provide a structured, queryable record of all
   logical replication conflicts. The current approach of logging conflicts as
   plain text in the server logs makes it difficult to query, analyze, and
   use for external monitoring and automation.
   
   This patch addresses these limitations by introducing a configurable
   conflict_log_table option in the CREATE SUBSCRIPTION command. Key design
   decisions include:
   
   User-Managed Table: The conflict log is stored in a user-managed table
   rather than a system catalog.
   
   Structured Data: Conflict details, including the original and remote tuples,
   are stored in JSON columns, providing a flexible format to accommodate different
   table schemas.
   
   Comprehensive Information: The log table captures essential attributes such as
   local and remote transaction IDs, LSNs, commit timestamps, and conflict type,
   providing a complete record for post-mortem analysis.
   
   This feature will make logical replication conflicts easier to monitor and manage,
   significantly improving the overall resilience and operability of replication setups.
   
   The conflict log tables will not be included in a publication, even if the publication
   is configured to include ALL TABLES or ALL TABLES IN SCHEMA.
   
   Note: A single remote tuple may conflict with multiple local tuples when conflict type
   is CT_MULTIPLE_UNIQUE_CONFLICTS, so for handling this case we create a single row in
   conflict log table with respect to each remote conflict tuple even if it conflicts with
   multiple local tuples and we store the multiple conflict tuples as a single JSON array
   element in format as
   [ { "xid": "1001", "commit_ts": "...", "origin": "...", "tuple": {...} }, ... ]
   We can extract the elements of the local tuples from the conflict log table row
   as given in below example.
   
   SELECT remote_xid, relname, remote_origin, local_conflicts[1] ->> 'xid' AS local_xid,
          local_conflicts[1] ->> 'tuple' AS local_tuple
   FROM myschema.conflict_log_history2;
   
    remote_xid | relname  | remote_origin | local_xid |     local_tuple
   ------------+----------+---------------+-----------+---------------------
           760 | test     | pg_16406      | 771       | {"a":1,"b":10}
           765 | conf_tab | pg_16406      | 775       | {"a":2,"b":2,"c":2}

   Dilip Kumar authored and Commitfest Bot committed Dec 11, 2025
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2. [CF 6252] v11 - Proposal: Conflict log history table for Logical Repl… …

   …ication
   
   This branch was automatically generated by a robot using patches from an
   email thread registered at:
   
   https://commitfest.postgresql.org/patch/6252
   
   The branch will be overwritten each time a new patch version is posted to
   the thread, and also periodically to check for bitrot caused by changes
   on the master branch.
   
   Patch(es): https://www.postgresql.org/message-id/CAFiTN-vrKc6OWzrg6yvpwYcj79k=zkrDp3uwiZzjwrWLJAq6tw@mail.gmail.com
   Author(s): Dilip Kumar

   Commitfest Bot committed Dec 11, 2025
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