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From Jonathan Ellis <>
Subject Re: Row slice / cache performance
Date Mon, 03 May 2010 15:37:55 GMT
On Sun, May 2, 2010 at 1:00 PM, James Golick <> wrote:
> the ConcurrentSkipListMap (ColumnFamily.columns_).
> SliceQueryFilter.getMemColumnIterator @ ~30% - Virtually all the time in
> here is spent in ConcurrentSkipListMap$Values.toArrray()

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

Created for this.

Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support

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