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https://issues.apache.org/jira/browse/CASSANDRA-799?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12834934#action_12834934
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Jonathan Ellis commented on CASSANDRA-799:
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stu, there is tension here between the goals of "decouple" and "encapsulate" --
either CFS cheats and does part of the work that should be in MT/BMT, special
casing as necessary, the way we had it before, or we let MT r/m itself from the
pending list.
since MT is already reaching in to CFS in places (this is far from the only
place, check again -- the way it was before it was looking up CFS by table/cf
name, which isn't really decoupled, it's just sloppy) I think I prefer the
latter since then at least we are being consistent.
> memtable sort is the bottleneck for range query performance
> -----------------------------------------------------------
>
> Key: CASSANDRA-799
> URL: https://issues.apache.org/jira/browse/CASSANDRA-799
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Jonathan Ellis
> Assignee: Jonathan Ellis
> Priority: Minor
> Fix For: 0.6
>
> Attachments:
> 0001-refactor-IFlushable-contract-to-push-differences-b-t-M.txt,
> 0002-use-a-sorted-map-for-memtable-contents-to-make-range-q.txt,
> 0003-refactor-to-make-memtablesPendingFlush-a-member-variab.txt,
> 799-unbounded-flushwriter.txt, 799.txt
>
>
> The obvious remedy is to use a sorted map. Unfortunately, keeping the map
> sorted constantly w/ TreeMap was about 30% slower than HashMap + sort back
> when we were doing manual locking. Let's see what the overhead is for
> ConcurrentSkiplistMap vs NBHM.
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