apache/seatunnel · error

A deserialization failure event arrived

Error message

A deserialization failure event arrived

What it means

The binlog client delivered an EventDeserializer.DeserializationException event to the connector. The message is logged at WARN, DEBUG, or ERROR depending on event.deserialization.failure.handling.mode; in FAIL mode the error handler's producer throwable is set (connector stops), in WARN mode streaming continues, otherwise it is logged at DEBUG.

Source

Thrown at seatunnel-connectors-v2/connector-cdc/connector-cdc-mysql/src/main/java/io/debezium/connector/mysql/MySqlStreamingChangeEventSource.java:1571

            try {
                // Stop BinaryLogClient background threads
                client.disconnect();
            } catch (final Exception e) {
                LOGGER.debug("Exception while closing client", e);
            }
            errorHandler.setProducerThrowable(wrap(ex));
        }

        @Override
        public void onEventDeserializationFailure(BinaryLogClient client, Exception ex) {
            if (eventDeserializationFailureHandlingMode
                    == EventProcessingFailureHandlingMode.FAIL) {
                LOGGER.debug("A deserialization failure event arrived", ex);
                logStreamingSourceState();
                errorHandler.setProducerThrowable(wrap(ex));
            } else if (eventDeserializationFailureHandlingMode
                    == EventProcessingFailureHandlingMode.WARN) {
                LOGGER.warn("A deserialization failure event arrived", ex);
                logStreamingSourceState(Level.WARN);
            } else {
                LOGGER.debug("A deserialization failure event arrived", ex);
                logStreamingSourceState(Level.DEBUG);
            }
        }
    }

    @FunctionalInterface
    private interface TableIdProvider<E extends EventData> {
        TableId getTableId(E data);
    }

    @FunctionalInterface
    private interface RowsProvider<E extends EventData, U> {
        List<U> getRows(E data);
    }
}

View on GitHub (pinned to cf67b549a7)

Solutions

1. Inspect the wrapped exception and use mysqlbinlog --start-position/--stop-position --verbose on the reported file/position to examine the event
2. Upgrade the Debezium-based connector version to match or exceed the source MySQL version
3. If the binlog is corrupt, restart streaming from a clean earlier offset/GTID or re-snapshot
4. Decide the desired policy: set event.deserialization.failure.handling.mode=fail to stop on bad events, or warn to skip them (risk of data loss)

Example fix

// before
"event.deserialization.failure.handling.mode": "warn"
// after (stop instead of silently skipping unreadable events)
"event.deserialization.failure.handling.mode": "fail"

// Before streaming:
// SELECT @@version; -- connector Debezium must support this MySQL version
// mysqlbinlog --verify-binlog-checksum <file>; -- binlog integrity

try {
    handleEvent(deserialized);
} catch (DeserializationException ex) {
    switch (failureMode) {
        case FAIL: errorHandler.setProducerThrowable(wrap(ex)); break;
        case WARN: logAndSkip(ex); break;
        default:   logDebugAndSkip(ex); break;
    }
}

When it happens

Trigger: execute()'s event loop receives a deserialization exception from the binlog client; handling mode is FAIL (stops via errorHandler.setProducerThrowable), WARN (continues), or default/other (debug log) — all paths log 'A deserialization failure event arrived'.

Common situations: Truncated binlogs after a server crash; binlog events written by a newer MySQL version than the connector supports; corrupted binlog transfer over network; reading GTID ranges spanning incompatible servers.

Understand the failure class

Background: "failed to unmarshal" / json.Unmarshal errors: why parsing a response into a Go struct fails and how to fix it — this error's family across 23 libraries.

Related errors

• Error while deserializing binlog event at offset {}.{}This e
• Unexpected error while connecting to MySQL and looking at gt
• Unexpected error while connecting to MySQL and looking for b
• Unexpected error while connecting to MySQL and looking at BI
• Unexpected error while connecting to MySQL and looking at BI

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/ddbebf21683a8a59. Report an issue: GitHub.