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Date: Thu, 7 Jul 2011 16:35:16 +0000 (UTC)
From: "Paul Loy (JIRA)" <jira@apache.org>
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Subject: [jira] [Updated] (CASSANDRA-2820) Re-introduce
 FastByteArrayInputStream (and Output equivalent)
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     [ https://issues.apache.org/jira/browse/CASSANDRA-2820?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Paul Loy updated CASSANDRA-2820:
--------------------------------

    Attachment: fast_bytearray_iostreams_harmony-patch-4.txt

More like my original:
* extends Input/OutputStream
* change uses of ByteArrayInputStream to use InputStream
* uses of ByteArrayOutputStream have to now know they are using FastByteArrayOutputStream as that has the #toArray() method.

> Re-introduce FastByteArrayInputStream (and Output equivalent)
> -------------------------------------------------------------
>
>                 Key: CASSANDRA-2820
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-2820
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>    Affects Versions: 0.8.0
>         Environment: n/a
>            Reporter: Paul Loy
>            Priority: Minor
>              Labels: bytearrayinputstream, bytearrayoutputstream, license, synchronized
>             Fix For: 1.0
>
>         Attachments: fast_bytearray_iostreams_harmony-patch-2.txt, fast_bytearray_iostreams_harmony-patch-3.txt, fast_bytearray_iostreams_harmony-patch-4.txt
>
>
> In https://issues.apache.org/jira/browse/CASSANDRA-37 FastByteArrayInputStream and FastByteArrayOutputStream were removed due to being code copied from the JDK and then subsequently modified. The JDK license is incompatible with Apache 2 license so the code had to go.
> I have since had a look at the performance of the JDK ByteArrayInputStream and a FastByteArrayInputStream (i.e. one with synchronized methods made un-synchronized) and seen the difference is significant.
> After a warmup-period of >10000 loops I get the following for 10000 loops through a 128000 byte array:
> bais : 3513ms
> fbais: 72ms
> This varies depending on the OS, machine and Java version, but it's always in favour of the FastByteArrayInputStream as you might expect.
> Then, at Jonathan Ellis' suggestion, I tried this using a modified Apache Harmony ByteArrayInputStream - i.e. one whose license is compatible - and the results were the same. A significant boost.
> I will attach a patch with changes for the 0.8.0 tag.

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