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https://issues.apache.org/jira/browse/CASSANDRA-5351?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13863946#comment-13863946
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Marcus Eriksson commented on CASSANDRA-5351:
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this is what i have so far;
* CompactionTask
- should be kept generic, move the compaction strategy specific stuff into
the classes (we still want to support users writing their own strategies)
* CompactionManager
- Calculates merkle trees over all data, not just the new unrepaired stuff.
- Marks all data as compacting (should only mark the unrepaired sstables as
compacting).
- Since we need to keep the involved sstables from getting compacted during
the whole repair, we might have to add a timeout - if repair hangs, we would
essentially stop compacting the new data. We might also need a "fall back to
repair-everything if the amount of new data is more than X"-config variable to
avoid blocking compactions
- Don't use System.nanoTime() as repairedAt time - nanoTime should only be
used to measure time between two events in the same jvm. Use
System.currentTimeMillis() instead.
> Avoid repairing already-repaired data by default
> ------------------------------------------------
>
> Key: CASSANDRA-5351
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5351
> Project: Cassandra
> Issue Type: Task
> Components: Core
> Reporter: Jonathan Ellis
> Assignee: Lyuben Todorov
> Labels: repair
> Fix For: 2.1
>
> Attachments: 5351_node1.log, 5351_node2.log, 5351_node3.log,
> 5351_nodetool.log
>
>
> Repair has always built its merkle tree from all the data in a columnfamily,
> which is guaranteed to work but is inefficient.
> We can improve this by remembering which sstables have already been
> successfully repaired, and only repairing sstables new since the last repair.
> (This automatically makes CASSANDRA-3362 much less of a problem too.)
> The tricky part is, compaction will (if not taught otherwise) mix repaired
> data together with non-repaired. So we should segregate unrepaired sstables
> from the repaired ones.
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