alibaba/canal · error · CanalClientException

mq get/ack not support concurrent & async ack

Error message

mq get/ack not support concurrent & async ack

What it means

Error "mq get/ack not support concurrent & async ack" thrown in alibaba/canal.

Source

Thrown at client/src/main/java/com/alibaba/otter/canal/client/rabbitmq/RabbitMQCanalConnector.java:196

    public void rollback(long batchId) throws CanalClientException {
        throw new CanalClientException("mq not support this method");

    }

    @Override
    public List<Message> getList(Long timeout, TimeUnit unit) throws CanalClientException {
        List<Message> messages = getListWithoutAck(timeout, unit);
        if (messages != null && !messages.isEmpty()) {
            ack();
        }
        return messages;
    }

    @Override
    public List<Message> getListWithoutAck(Long timeout, TimeUnit unit) throws CanalClientException {
        try {
            if (this.lastGetBatchMessage != null) {
                throw new CanalClientException("mq get/ack not support concurrent & async ack");
            }

            ConsumerBatchMessage batchMessage = messageBlockingQueue.poll(timeout, unit);
            if (batchMessage != null) {
                this.lastGetBatchMessage = batchMessage;
                return batchMessage.getData();
            }
        } catch (InterruptedException ex) {
            logger.warn("Get message timeout", ex);
            throw new CanalClientException("Failed to fetch the data after: " + timeout);
        }
        return Lists.newArrayList();
    }

    @Override
    public List<FlatMessage> getFlatList(Long timeout, TimeUnit unit) throws CanalClientException {
        List<FlatMessage> messages = getFlatListWithoutAck(timeout, unit);
        if (messages != null && !messages.isEmpty()) {

View on GitHub (pinned to 87be50e876)

Solutions

1. Disable concurrent/async ack for the RabbitMQ connector; process and ack batches sequentially.
2. Use getWithoutAck with manual ack only from a single consumer thread.

When it happens

Trigger: Thrown at client/src/main/java/com/alibaba/otter/canal/client/rabbitmq/RabbitMQCanalConnector.java:196 when the library encounters an invalid state.

Common situations: Concurrent async ack on RabbitMQ connector. Serialize acks per batch; concurrent acknowledgements on one channel are not supported by the client.

AI-assisted analysis of alibaba/canal@87be50e876 (2026-08-14). Data as JSON: /api/errors/42154fb2c738caf0. Report an issue: GitHub.