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https://issues.apache.org/jira/browse/HBASE-15259?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15149172#comment-15149172
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Enis Soztutar commented on HBASE-15259:
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Yep, seems like a bug. Replication is used in two different settings today
(1)"distributed log replay" and (2) region replicas. Dist log replay is going
away from my understanding, after many years it is still not stable enough.
Region replicas skip the WAL when the edit is replicated so it may not be a
problem. We can still fix this I think by reordering the setScopes(null) call.
> WALEdits under replay will also be replicated
> ---------------------------------------------
>
> Key: HBASE-15259
> URL: https://issues.apache.org/jira/browse/HBASE-15259
> Project: HBase
> Issue Type: Bug
> Reporter: ramkrishna.s.vasudevan
> Assignee: ramkrishna.s.vasudevan
> Priority: Minor
> Attachments: HBASE-15259.patch
>
>
> I need to verify this but seeing the code
> {code}
> try {
> // We are about to append this edit; update the region-scoped
> sequence number. Do it
> // here inside this single appending/writing thread. Events are
> ordered on the ringbuffer
> // so region sequenceids will also be in order.
> regionSequenceId = entry.stampRegionSequenceId();
> // Edits are empty, there is nothing to append. Maybe empty when we
> are looking for a
> // region sequence id only, a region edit/sequence id that is not
> associated with an actual
> // edit. It has to go through all the rigmarole to be sure we have
> the right ordering.
> if (entry.getEdit().isEmpty()) {
> return;
> }
> // Coprocessor hook.
> if (!coprocessorHost.preWALWrite(entry.getHRegionInfo(),
> entry.getKey(),
> entry.getEdit())) {
> if (entry.getEdit().isReplay()) {
> // Set replication scope null so that this won't be replicated
> entry.getKey().setScopes(null);
> }
> }
> if (!listeners.isEmpty()) {
> for (WALActionsListener i: listeners) {
> // TODO: Why does listener take a table description and CPs take
> a regioninfo? Fix.
> i.visitLogEntryBeforeWrite(entry.getHTableDescriptor(),
> entry.getKey(),
> entry.getEdit());
> }
> }
> {code}
> When a WALEdit is in replay we set the Logkey to null. But in the
> visitLogEntryBeforeWrite() we again set the LogKey based on the replication
> scope associated with the cells. So the previous step of setting null does
> not work here?
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