[
https://issues.apache.org/jira/browse/ZOOKEEPER-4883?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
ASF GitHub Bot updated ZOOKEEPER-4883:
--------------------------------------
Labels: pull-request-available (was: )
> Rollover leader epoch when counter part of zxid reach limit
> -----------------------------------------------------------
>
> Key: ZOOKEEPER-4883
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-4883
> Project: ZooKeeper
> Issue Type: Improvement
> Components: server
> Reporter: Kezhu Wang
> Assignee: Kezhu Wang
> Priority: Major
> Labels: pull-request-available
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Currently, zxid rollover will cause re-election(ZOOKEEPER-1277) which is time
> consuming.
> ZOOKEEPER-2789 proposes to use 24 bits for epoch and 40 bits for counter. I
> do think it is promising as [it promotes rollover rate from 49.7 days to 34.9
> years assuming 1k/s
> ops|https://github.com/apache/zookeeper/pull/2164#issuecomment-2368107479].
> But I think it is a one-way ticket. And the change of data format may require
> community wide spread to upgrade third party libraries/tools if they are ever
> tied to this. Inside ZooKeeper, `accepetedEpoch` and `currentEpoch` are tied
> to `zxid`. Given a snapshot and a txn log, we need probably deduced those two
> epoch values to join quorum.
> So, I presents alternative solution to rollover leader epoch when counter
> part of zxid reach limit.
> # Treats last proposal of an epoch as rollover proposal.
> # Requests from next epoch are proposed normally.
> # Fences next epoch once rollover proposal persisted.
> # Proposals from next epoch will not be written to disk before rollover
> committed.
> # Leader commits rollover proposal once it get quorum ACKs.
> # Blocked new epoch proposals are logged once rollover proposal is committed
> in corresponding nodes.
>
> This results in:
> # No other lead cloud lead using next epoch number once rollover proposal is
> considered committed.
> # No proposals from next epoch will be written to disk before rollover
> proposal is considered committed.
> Here is the branch, I will draft a pr later.
> https://github.com/kezhuw/zookeeper/tree/zxid-rollover
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
