visortelle commented on code in PR #712: URL: https://github.com/apache/pulsar-site/pull/712#discussion_r1508058566
########## docs/txn-advanced-features.md: ########## @@ -37,10 +37,33 @@ If you want to enable authentication with transactions, follow the steps below. 2. [Configure authentication](security-overview/#authentication) in a Pulsar client. +## Select transaction isolation level + +To enhance the flexibility of Pulsar transactions, they support two distinct isolation levels: +- `READ_COMMITTED`(default): The consumer can only consume all transactional messages that have been committed. +- `READ_UNCOMMITTED`: The consumer can consume all messages, even transactional messages that have been aborted. + +For different scenarios, they use different subscriptions and choose different isolation levels. One scenario might require transactions, while another might not. In general, not all subscriptions of the same topic require transaction guarantees. Some want low latency without the exact-once semantic guarantee (like a real-time monitoring system), and some must require the exactly-once guarantee (e.g., business processing systems). +Users can freely choose different isolation levels according to different scenarios. + +Note that this is a subscription dimension configuration, and all consumers under the same subscription need to be configured with the same IsolationLevel. Review Comment: ```suggestion Note that this is a subscription-level configuration, and all consumers under the same subscription must be configured with the same `IsolationLevel`. ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
