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https://issues.apache.org/jira/browse/HBASE-29776?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18044757#comment-18044757
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Hernan Gelaf-Romer commented on HBASE-29776:
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[~dieterdp_ng] Can you help sanity check me a little? I feel that this
conditional shouldn't exist at all. I don't think we should ever filter out an
oldWAL for backing up. I can see two scenarios for data loss here
# The conditional just seems wrong, and contradicts the comment. If the
newTimestamp is null (and therefore the RS is obsolete), we filter it out from
being backed up
# newTimestamp represents the last time a backup rolled the WAL on the RS. Why
would we filter out oldWALs that have been created since then? That seems wrong
as well
> Log filtering in IncrementalBackupManager can lead to data loss
> ---------------------------------------------------------------
>
> Key: HBASE-29776
> URL: https://issues.apache.org/jira/browse/HBASE-29776
> Project: HBase
> Issue Type: Bug
> Components: backup&restore
> Reporter: Hernan Gelaf-Romer
> Priority: Major
>
> At the moment, incremental backups will filter out old wals that belong to RS
> which do not have any active WAL files.
>
> The code
>
> {code:java}
> // It is possible that a host in .oldlogs is an obsolete region server
> // so newestTimestamps.get(host) here can be null.
> // Even if these logs belong to a obsolete region server, we still need
> // to include they to avoid loss of edits for backup.
> Long newTimestamp = newestTimestamps.get(host);
> if (newTimestamp == null || currentLogTS > newTimestamp) {
> newestLogs.add(currentLogFile);
> }{code}
> Is doing the opposite of what the comment (correctly) says.
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