[ 
https://issues.apache.org/jira/browse/CASSANDRA-5351?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13775569#comment-13775569
 ] 

Benjamin Coverston commented on CASSANDRA-5351:
-----------------------------------------------

Worst case scenario we hit double the number of SSTables (assuming that 
un-repaired has the same number of levels and a key for the query in each).

Best case scenario you're not updating the same data, so it gets filtered out 
in the interval tree query. 

The interval tree doesn't really discriminate between levels, they're all in 
the same pool, you just get the set of intersected SSTables.
                
> 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 is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Reply via email to