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https://issues.apache.org/jira/browse/CASSANDRA-1046?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Matthew F. Dennis updated CASSANDRA-1046:
-----------------------------------------

    Attachment: insertarator.py
                readarator.py
                0001-trunk-cassandra-1046.patch

> optimize Memtable.getSliceIterator
> ----------------------------------
>
>                 Key: CASSANDRA-1046
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1046
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Jonathan Ellis
>            Assignee: Matthew F. Dennis
>             Fix For: 0.7
>
>         Attachments: 0001-trunk-cassandra-1046.patch, insertarator.py, 
> readarator.py
>
>
> As reported by James Golick, about 30% of the time in a read is spent in 
> SliceQueryFilter.getMemColumnIterator, virtually all of which is in 
> ConcurrentSkipListMap$Values.toArrray().
> I wrote on the ML:
> Besides the UUID optimization you posted, we should do an audit of 
> ColumnFamily.getSortedColumns and replace with iteration where possible (in 
> this case, we'd be left with one copy of most of the columns, but that's 
> better than two).
> We can get rid of the other copy by fixing the logic in 
> Memtable.getSliceIterator, which says "copy all the columns, so we can do a 
> binary search on them to find where to start," but since columns are natively 
> in sorted order we could just use an iterator and a while loo

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