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From "Jonathan Ellis (JIRA)" <j...@apache.org>
Subject [jira] Commented: (CASSANDRA-1945) Use EHcache for row cache + disk spillover
Date Tue, 11 Jan 2011 14:54:46 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-1945?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12980129#action_12980129
] 

Jonathan Ellis commented on CASSANDRA-1945:
-------------------------------------------

Sounds like BigMemory pushes everything through Java serialization, which is a huge ouch.
 Their page says

"Because off-heap data is stored in bytes, there are two implications:
    * "Only Serializable cache keys and values can be placed in the store, similar to DiskStore.
    * "Serialization and deserialization take place on putting and getting from the store.
This means that the off-heap store is slower in an absolute sense (around 10 times slower
than the MemoryStore)"

10x slower is awfully close to "don't bother with rowcache and just rebuild it using the OS
page cache to cache the underlying sstable bytes" territory for us.

> Use EHcache for row cache + disk spillover
> ------------------------------------------
>
>                 Key: CASSANDRA-1945
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1945
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: T Jake Luciani
>            Assignee: Vijay
>         Attachments: 0001-Config-1945.txt, 0002-Update_existing-1945.txt, 0003-New_Cache_Providers-1945.txt,
BB_Cache.png, ehcache-1.6.2.jar, EhCache-OSS.png, JMX-Cache.png, JMX-EhCache.png, Old_Cahce.png
>
>
> Ehcache does a nice job of spilling over to disk and its ASL2
> http://www.ehcache.org/license.html
> Also, the commercial version supports Smaller JVM sizes via it's BigMemory product
> http://www.terracotta.org/bigmemory

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