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https://issues.apache.org/jira/browse/HBASE-2195?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13099893#comment-13099893
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stack commented on HBASE-2195:
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@Ted I see what you are saying. But if we add in VersionedWritable, he'll not
be able to do his trick where he can deserialize this version of HLogKey and
the previous one (since it will read a byte off the stream and treat it as the
version regardless). As I see it, we can:
+ Leave patch as is. Then later, if we need to change HLogKey, we'll up the
version to '0' ('0' is an unlikely length on an vint for encoded name). So
we've squeezed an extra version in. Thereafter we'd have to move to use
versions 1, 2, 3, etc. If we ever encountered a WAL that had HLogKeys written
before this patch, we'd not be able to deserialize them since we'd confuse them
with these newer 1, 2, 3.. versions. I think that should be fine since a good
bit of time will have passed between the two version and deserializing old
stuff will be less likely.
+ We move to VersionedWritable now but that'll break our being able to read
WALs written before this patch went in.
Like I say, I think the second option above tolerable given as we're going to a
major version and we can state we can't read WALs across versions but it seems
like leaving the patch as is, option 1, gives us most flexibility (we can read
old WALs).
What you think Ted?
> Support cyclic replication
> --------------------------
>
> Key: HBASE-2195
> URL: https://issues.apache.org/jira/browse/HBASE-2195
> Project: HBase
> Issue Type: Sub-task
> Components: replication
> Reporter: Jean-Daniel Cryans
> Assignee: Lars Hofhansl
> Attachments: 2195-v10.txt, 2195-v12.txt, 2195-v5.txt, 2195-v6.txt,
> 2195.txt
>
>
> We need to support cyclic replication by using the cluster id of each HlogKey
> and stop replicating when it goes back to the original cluster.
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