XACK command in Redis is used in the context of stream data structures for acknowledging the processing of a message. Common use cases include distributed message queues and real-time data processing systems where it's crucial to keep track of which messages have been successfully processed.
Assuming you're using the Predis library, below are examples of how to use the
In this example, we acknowledge one message identified by its ID (
$messageId) from the stream called
mystream that was read by the consumer group
In this example, we acknowledge multiple messages at once. The
xack method takes an array of message IDs.
1. What happens if I forget to acknowledge a message?
If a message is not acknowledged, Redis will consider that message as unprocessed or pending. It might be delivered again when the pending messages are queried.
2. Can I acknowledge the message for a different consumer group?
No, you can only acknowledge messages for the specific consumer group that fetched the message.