[GitHub] [pulsar] startjava created a discussion: what is "滚动策略循环"?

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GitHub user startjava created a discussion: what is "滚动策略循环"?

https://www.jianshu.com/p/168db3b69fac

一个 stream 由多个 ledger 组成；每个 ledger 根据基于时间或空间的滚动策略循环。

@sijie 

how do loop??

GitHub link: https://github.com/apache/pulsar/discussions/18471

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[GitHub] [pulsar] startjava added a comment to the discussion: what is "滚动策略循环"?

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GitHub user startjava added a comment to the discussion: what is "滚动策略循环"?

https://pulsar.apache.org/docs/next/concepts-architecture-overview/#managed-ledgers

A ledger can be deleted when all cursors have consumed the messages it contains. This allows for periodic rollover of ledgers.

“periodic rollover of ledgers”

what is rollover of ledgers ? how rollover??

ledgers not delete, from begin write data ??





GitHub link: https://github.com/apache/pulsar/discussions/18471#discussioncomment-4143453

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[GitHub] [pulsar] MarvinCai added a comment to the discussion: what is "滚动策略循环"?

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GitHub user MarvinCai added a comment to the discussion: what is "滚动策略循环"?

Rollover means delete old(consumed) ledgers and make room for new ledgers.
Ledger is append only and will not be writable once closed/fenced.
Ledger can only be deleted as a whole, so all entries on a ledger has to be consumed and acked by consumers(or auto acked by ttl).
Broker will scan ledger at background and if a ledger is fullly consumer(all entries are consumed) & (ledger exists more than configured retention period || total storage size for a topic cross max retion size), then it's marked for delete(rollover).


GitHub link: https://github.com/apache/pulsar/discussions/18471#discussioncomment-4254595

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