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https://issues.apache.org/jira/browse/IOTDB-439?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17029508#comment-17029508
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Tian Jiang commented on IOTDB-439:
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2.a. If you have concrete advice, it is welcomed. But using "synchronized" can
minimize the scope being locked, as far as I see, I do not think there is any
problem.
2.b. Performance concerns are currently left behind, and there is no proof
supporting that. And for correctness, synchronization is necessary. Tightening
the scope needed to be synchronized may be a good optimization, but it is too
early for now.
> [Distributed] Incorrect Snapshot implementation and LogManager
> --------------------------------------------------------------
>
> Key: IOTDB-439
> URL: https://issues.apache.org/jira/browse/IOTDB-439
> Project: Apache IoTDB
> Issue Type: Sub-task
> Reporter: Xiangdong Huang
> Priority: Major
>
> I read the log/snapshot and manage packages in current cluster_new branch,
> and have some questions:
> 1. PartitionedSnapshotLogManager and FilePartitionedSnapshotLogManager are
> incorrect as
> a. they still store log into memory while the JavaDoc says they do not
> store data in memory.
> b. When doing snapshot, do they need to consider the part of the log in
> memory?
>
> 2. Current LogManager is not thread-safety. The caller (i.e., RaftMember)
> uses sync keyword to guarantee that for each call.
> a. a better design?
> b. is there any performance problem? as all operations are serialization.
>
> 3. Consider the Raft Protocol, don't we need APIs like
> `removeLogFrom(startIndex)` in LogManager? see the case of Figure 7 in Raft
> paper [1]
>
> [1] [https://raft.github.io/raft.pdf]
>
> [~jt2594838] may know clearly about current implementation.
>
>
>
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