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https://issues.apache.org/jira/browse/CASSANDRA-1046?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12875739#action_12875739
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Jonathan Ellis commented on CASSANDRA-1046:
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to clarify, the "these changes" that made it fast is
0001-trunk-cassandra-1046.patch ? or some combination of the patch, and
improved client code?
> 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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