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https://issues.apache.org/jira/browse/CASSANDRA-51?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jonathan Ellis updated CASSANDRA-51:
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    Fix Version/s: 0.3

>  Memory footprint for memtable
> ------------------------------
>
>                 Key: CASSANDRA-51
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-51
>             Project: Cassandra
>          Issue Type: Improvement
>         Environment: all
>            Reporter: Sandeep Tata
>            Assignee: Eric Evans
>             Fix For: 0.3
>
>
> The implementation of EfficientBidiMap(EBM) today stores the column in two 
> place, a map and a sorted set. Both data structures store exactly the same 
> values.
> I assume we're storing this twice so that the map can give us O(1) reads 
> while the sortedset is important for efficient flush. Is this tradeoff 
> important ? Do we want to store the data twice to get O(1) reads over 
> O(log(n)) reads from sortedset? Is the sortedset implementation broken? 
> Perhaps we should consider a configuration option that turns off the map -- 
> write performance will be slightly improved, read performance will be 
> somewhat worse, and the memory footprint will probably be about half. 
> Certainly sounds like a good alternative tradeoff.

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