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From "Johan Oskarsson (JIRA)" <j...@apache.org>
Subject [jira] Updated: (CASSANDRA-950) Cache BufferedRandomAccessFile.length
Date Sat, 03 Apr 2010 12:17:27 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-950?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Johan Oskarsson updated CASSANDRA-950:
--------------------------------------

    Attachment: CASSANDRA-950.patch

With this patch a microbenchmark shows an order of magnitude less time spent in length().
The method no longer shows up in the profiler "cpu burn" tree, down from 23%. Added unit test
for the method.

> Cache BufferedRandomAccessFile.length
> -------------------------------------
>
>                 Key: CASSANDRA-950
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-950
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Johan Oskarsson
>         Attachments: CASSANDRA-950.patch
>
>
> Profiling shows that BufferedRandomAccessFile.length is eating up an unexpected amount
of cpu. It believe it is the call through the "native barrier" that is causing it. We often
call the length method via is end of file when reading data. We can add caching of the file
length to avoid this call most times.

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