WAL stream loop ended abnormally.

[venkatramachandran]

Every morning at the same time, getting this error. Postgres DBA is saying all looks fine at his end. In Qlik Replicate server nothing seems to be wrong and all other tasks are running good.

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02686621: 2025-02-13T04:07:23 [PERFORMANCE ]T: Source latency 0.97 seconds, Target latency 0.97 seconds, Handling latency 0.00 seconds (replicationtask.c:3875)
02686625: 2025-02-13T04:07:26 [SOURCE_CAPTURE ]I: End of CDC / CAPTURE events for POSTGRES endpoint. (postgres_endpoint_capture.c:557)
02686625: 2025-02-13T04:07:26 [SOURCE_CAPTURE ]I: CAPTURE ended with exceptions. (postgres_endpoint_capture.c:564)
02686625: 2025-02-13T04:07:26 [SOURCE_CAPTURE ]E: WAL stream loop ended abnormally. (STATUS_RECOVERABLE) [1020452] (postgres_endpoint_wal_engine.c:1491)
02686625: 2025-02-13T04:07:26 [SOURCE_CAPTURE ]E: WAL reader terminated with broken connection / recoverable error. [1020458] (postgres_endpoint_capture.c:542)
02686621: 2025-02-13T04:07:26 [TASK_MANAGER ]I: Task error notification received from subtask 0, thread 0, status 1020458 (replicationtask.c:3600)
02686625: 2025-02-13T04:07:26 [SOURCE_CAPTURE ]E: Error executing source loop [1020458] (streamcomponent.c:1944)
02686625: 2025-02-13T04:07:26 [TASK_MANAGER ]E: Stream component failed at subtask 0, component st_0_s-PG-coll_billing_svc_db [1020458] (subtask.c:1463)
02686625: 2025-02-13T04:07:26 [SOURCE_CAPTURE ]E: Stream component 'st_0_s-PG-coll_billing_svc_db' terminated [1020458] (subtask.c:1634)
02

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[john_wang]

Hello @venkatramachandran ,

Determining the root cause based solely on the error messages can be challenging. We recommend the following steps:

1. Enable WAL Heartbeat

   • Navigate to Source Endpoint Properties → Advanced and enable "WAL heartbeat".
   • The default heartbeat frequency is 5 minutes.

2. Check Server-Side Configuration

   • Verify the wal_sender_timeout setting.
   • If possible, increase it to a higher value, such as one hour (I do not recommend setting it to 0).
   • Check if this resolves the issue.

3. Enable Verbose Logging

   • If the problem persists, set source_capture to Verbose and reproduce the error.
   • This will allow us to investigate further.

Hope this helps.

John.