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Date: Fri, 6 Sep 2013 12:40:57 +0000 (UTC)
From: "Anoop Sam John (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
Message-ID: <JIRA.12496970.1296154159469.91380.1378471257811@arcas>
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Subject: [jira] [Commented] (HBASE-3484) Replace memstore's
 ConcurrentSkipListMap with our own implementation
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    [ https://issues.apache.org/jira/browse/HBASE-3484?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13760178#comment-13760178 ] 

Anoop Sam John commented on HBASE-3484:
---------------------------------------

In current patch the max size of the memstore slice is specified in terms of heap size. But what matters is the #entries in the CSLM. I am thinking this can be #entries in the slice.
                
> Replace memstore's ConcurrentSkipListMap with our own implementation
> --------------------------------------------------------------------
>
>                 Key: HBASE-3484
>                 URL: https://issues.apache.org/jira/browse/HBASE-3484
>             Project: HBase
>          Issue Type: Improvement
>          Components: Performance
>    Affects Versions: 0.92.0
>            Reporter: Todd Lipcon
>            Priority: Critical
>         Attachments: hierarchical-map.txt, memstore_drag.png, WIP_HBASE-3484.patch
>
>
> By copy-pasting ConcurrentSkipListMap into HBase we can make two improvements to it for our use case in MemStore:
> - add an iterator.replace() method which should allow us to do upsert much more cheaply
> - implement a Set directly without having to do Map<KeyValue,KeyValue> to save one reference per entry
> It turns out CSLM is in public domain from its development as part of JSR 166, so we should be OK with licenses.

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