[
https://issues.apache.org/jira/browse/RATIS-2089?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17849619#comment-17849619
]
Ivan Andika commented on RATIS-2089:
------------------------------------
[~szetszwo] Thank you for the explanation
> The reply from Ratis server is a just MAJORITY, which means "replicated to a
> majority of peers" (the peers except for the leader may not be able to apply
> the log). MAJORITY_COMMITTED is more strict. It means "committed at a
> majority of peers" (i.e. they can apply the log locally).
I see, I thought it was MAJORITY_COMMITTED which I assumed from the Raft paper.
> btw, the hsync feature (HDDS-7593) is going to improve the latency and write
> performance
Sure, let me take a look for latency-related patches.
> Add CommitInfoProto in NotReplicatedException
> ---------------------------------------------
>
> Key: RATIS-2089
> URL: https://issues.apache.org/jira/browse/RATIS-2089
> Project: Ratis
> Issue Type: Improvement
> Reporter: Ivan Andika
> Assignee: Ivan Andika
> Priority: Minor
>
> In Ozone's XceiverClientRatis#watchForCommit, there are two watch commits
> request with different ReplicationLevel
> # Watch for ALL_COMMITTED
> # Watch for MAJORITY_COMMITTED (If the previous watch threw an exception)
> Based on the second watch request, the client will remove some failed
> datanode UUID from the commitInfoMap.
> The second watch might not be necessary since the entries in
> AbstractCommitWatcher.commitIndexMap implies that the PutBlock request has
> been committed to the majority of the servers. Therefore, another
> MAJORITY_COMMITTED watch might not be necessary. From my understanding, the
> second MAJORITY_COMMITTED only serves to gain information to remove entries
> from commitInfoMap.
> If the first watch failed with NotReplicatedException, we might be able to
> remove the need to a second watch request. Since NotReplicatedException is a
> Raft server exception, we can include the CommitInfoProtos in the
> NotReplicatedException. The client can use this CommitInfoProtos to remove
> the entry from commitInfoMap without sending another WATCH request.
> This CommitInfoProto is returned for every RaftClientReply
> (RaftClientReply.commitInfos), but if there is an exception, it seems the
> RaftClientReply is not accessible to the client.
> However, if the exception is a client exception (e.g. due to Raft client
> watch timeout configuration), the client might have no choice but to send
> another watch request.
> So in this patch, I propose to include CommitInfoProto into
> NotReplicatedException.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
