[
https://issues.apache.org/jira/browse/CASSANDRA-5351?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13801007#comment-13801007
]
Lyuben Todorov commented on CASSANDRA-5351:
-------------------------------------------
For STCS
The best choice seems like compacting into repaired sstables and unrepaired
sstables based on SSTableMetadata#repairedAt field.
For LCS
We have two main choices, Repair data going fromg L0 -> L1. Should be
reasonable since repairing at each promotion means we dont need to carry out a
lot of repairs during compaction, but it does mean we need to trigger repairs
automatically (I dont like the sound of extra work before/during compaction),
this is why I prefer [~krummas]'s idea of keeping separate levels of LCS. Next
step is to workout how the data at UnrepairedLevelN can jump to RepairedLevelN
without having to go through each level.
> 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
>
>
> 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.
--
This message was sent by Atlassian JIRA
(v6.1#6144)
