I got this error in the cdc postgress connector:

Postgres Debezium Connection Error: The sync encountered an unexpected error in the change event producer and has stopped. Please check the logs for details and troubleshoot accordingly.

And the cause is:

Caused by: java.lang.IllegalArgumentException:
  Unsupported message type: A
  at PgOutputMessageDecoder$MessageType.forType(.java:115)
  at PostgresStreamingChangeEventSource.processMessages(.java:236)

I'm sorry, but the knowledge sources do not contain enough information to provide a confident answer about this specific error —

IllegalArgumentException: Unsupported message type: A

from

PgOutputMessageDecoder

. Here's what I can tell you based on the available context: What's happening The error

Unsupported message type: A

means Debezium's

PgOutputMessageDecoder

received a WAL message type it doesn't recognize (type

"A"

). This is a Debezium-level parsing issue when reading from the PostgreSQL replication stream. The outer error you see: >

Postgres Debezium Connection Error: The sync encountered an unexpected error in the change event producer and has stopped.

is a known error pattern in the Postgres source connector that wraps unexpected Debezium failures. [Postgres error config] Suggested steps 1. Check your connector version — The knowledge sources indicate that many CDC-related bugs have been fixed in newer versions of the Postgres source connector (current release candidate is

3.8.0-rc.12

). If you're on an older version (e.g.,

3.6.x

), upgrading may resolve the issue. [Postgres CDC fix] 2. Check for recent schema changes — Unexpected WAL message types can sometimes be triggered by DDL operations (e.g.,

ALTER TABLE

) on the source database, which generate special WAL messages. 3. Reset the connection — As a workaround, try performing a "Refresh data" (full refresh reset) on the affected connection to re-establish the replication slot position. 4. Switch to Full Refresh temporarily — If the CDC sync continues to fail, switching the affected streams to Full Refresh mode can unblock you while the issue is investigated. [CDC issue workaround] 5. File a bug report — Since this specific error (

Unsupported message type: A

) is not covered in the available knowledge sources, I'd recommend opening a GitHub issue at airbytehq/airbyte with your connector version, PostgreSQL version, and full logs. 👍 0 button 👎 0 button ℹ️ Tip: Mention @kapa.ai in the thread for follow-ups or DM the app for 1-to-1 help.

@kapa.ai Other ai said this, evaluate: Recommended Actions 1. Upgrade

source-postgres

connector to a version bundling Debezium 1.6.0+ (this is a known fixed bug). 2. Immediate workaround: Set

proto_version=1

in the Airbyte source connection settings — disables in-progress transaction streaming, prevents

Stream Abort

messages, CDC continues to work. 3. Investigate source Postgres for large rolled-back transactions, which may be a separate application-level concern.

I cannot verify the accuracy of those recommendations based on the available knowledge sources. Here's my evaluation of each point: Evaluation 1. "Upgrade to Debezium 1.6.0+" Cannot verify — likely inaccurate. The knowledge sources reference Debezium versions

2.6.x

,

3.0.1.Final

, and

3.0.1.Final

in the context of recent connector versions. Debezium

1.6.0

is very old. The knowledge sources do not mention this version as a fix for

Unsupported message type: A

. [CDC PgJDBC issue] [IndexOutOfBounds issue] 2. "proto_version=1 workaround" Cannot verify — treat with caution. The knowledge sources make no mention of a

proto_version

setting in Airbyte's Postgres source connector configuration. This may be a raw Debezium parameter, but I cannot confirm it is exposed or supported in Airbyte's connector, nor that it addresses your specific error. 3. "Investigate large rolled-back transactions" Plausible but unverified. Large rolled-back transactions can generate WAL activity, but the knowledge sources do not link this to the

Unsupported message type: A

error specifically. What the knowledge sources do support • The

Unsupported message type: A

error is not documented in the available knowledge sources, so any specific fix claims should be treated skeptically. • Known working mitigations for Postgres CDC issues include: ◦ Resetting/refreshing the connection [CDC LSN issue] ◦ Switching affected streams to Full Refresh temporarily [timestamp error] ◦ Upgrading to the latest connector version (currently

3.8.0-rc.12

) [array fix PR] I'd strongly recommend opening a GitHub issue with Airbyte directly for a verified fix to your specific error. 👍 0 button 👎 0 button ℹ️ Tip: Mention @kapa.ai in the thread for follow-ups or DM the app for 1-to-1 help.