A recent log switch may not have been archived by the Oracle ARC process yet

[Deukryong Moon]

Hi Debezium Team, 

We have Debezium Server with the Oracle Connector, and we are getting the following log occasionally. As the severity of the LOG is INFO, we think this is not an major issue, but can you confirm please we can ignore this message?

Thanks!!!

2025-09-17 10:09:47,549 /opt/openjdk/jdk21.0.8/bin/java[74396] INFO  [io.deb.con.ora.log.LogFileCollector] (debezium-oracleconnector-mox-change-event-source-coordinator) Redo th
read 1 is inconsistent; does not have a log that conatins scn 63828007061. A recent log switch may not have been archived by the Oracle ARC process yet.: io.debezium.DebeziumException: Redo t
hread 1 is inconsistent; does not have a log that conatins scn 63828007061. A recent log switch may not have been archived by the Oracle ARC process yet.
        at io.debezium.connector.oracle.logminer.LogFileCollector.logException(LogFileCollector.java:567)
        at io.debezium.connector.oracle.logminer.LogFileCollector.isOpenThreadConsistent(LogFileCollector.java:279)
        at io.debezium.connector.oracle.logminer.LogFileCollector.isLogFileListConsistent(LogFileCollector.java:197)
        at io.debezium.connector.oracle.logminer.LogFileCollector.getLogs(LogFileCollector.java:88)
        at io.debezium.connector.oracle.logminer.AbstractLogMinerStreamingChangeEventSource.prepareLogsForMining(AbstractLogMinerStreamingChangeEventSource.java:1135)
        at io.debezium.connector.oracle.logminer.buffered.BufferedLogMinerStreamingChangeEventSource.executeLogMiningStreaming(BufferedLogMinerStreamingChangeEventSource.java:143)
        at io.debezium.connector.oracle.logminer.AbstractLogMinerStreamingChangeEventSource.execute(AbstractLogMinerStreamingChangeEventSource.java:209)
        at io.debezium.connector.oracle.logminer.AbstractLogMinerStreamingChangeEventSource.execute(AbstractLogMinerStreamingChangeEventSource.java:88)
        at io.debezium.pipeline.ChangeEventSourceCoordinator.streamEvents(ChangeEventSourceCoordinator.java:326)
        at io.debezium.pipeline.ChangeEventSourceCoordinator.executeChangeEventSources(ChangeEventSourceCoordinator.java:207)
        at io.debezium.pipeline.ChangeEventSourceCoordinator.lambda$start$0(ChangeEventSourceCoordinator.java:147)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
        at java.base/java.lang.Thread.run(Thread.java:1583)

[Chris Cranford]

Hi -

This is a great question and in practice, these messages are typically harmless. When an online redo log is scheduled for archival, it may take the ARC process some seconds before the archive log entry appears in the V$ARCHIVED_LOG performance view. During this window, the redo thread state is inconsistent, and we report this information this way. By default, the connector attempts to reconcile inconsistent redo threads over a total period of 60 seconds using 5 attempts with expontential back-off. In the event that the redo thread never reaches consistency, we'll report an error and the connector will stop. These INFO log messages are there to indicate why you may notice small stalls in the event stream as we cannot read any changes while logs are inconsistent.

So yes, these are typically harmless and are primarily informational only.

-cc

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