[BOOKKEEPER-10] Last hint for open ledger

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Done
• Assignee: Flavio Paiva Junqueira
• Reporter: Flavio Paiva Junqueira
• Created: 11/Jul/09 07:45
• Updated: 09/Oct/17 09:58
• Resolved: 09/Oct/17 09:58

Description

In some use cases of BookKeeper, it is useful to be able to read from a ledger before closing the ledger. To enable such a feature, the writer has to be able to communicate to a reader how many entries it has been able to write successfully. The main idea of this jira is to continuously update a znode with the number of successful writes, and a reader can, for example, watch the node for changes.

I was thinking of having a configuration parameter to state how often a writer should update the hint on ZooKeeper (e.g., every 1000 requests, every 10,000 requests). Clearly updating more often increases the overhead of writing to ZooKeeper, although the impact on the performance of writes to BookKeeper should be minimal given that we make an asynchronous call to update the hint.

Issue Links

• relates to: BOOKKEEPER-11 Read from open ledger