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https://issues.apache.org/jira/browse/CASSANDRA-2820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13060484#comment-13060484
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Sylvain Lebresne commented on CASSANDRA-2820:
---------------------------------------------
I'm actually not too much of a fan of extending ByteArray*Stream but
redeclaring all the fields, giving "fake" argument to the super constructor.
It's a bit ugly and not too optimal in memory size (the space argument is not a
huge one I agree). I think we should extend and reuse the protected field of
the super class. Those are part of the public API, so there is not so much
liberty over what a future Harmony implementation (or any implementation for
that matter) can do with them in the future and more importantly, if we
override all the methods, we don't care (expect for the call to the super
constructor actually, but it's easy enough to assert the validity of the field
assignation after the call to super() if we really want to). And talking about
that, we need to add an implementation of read(byte[]), flush() and
write(byte[]) because we can't be sure that the implementation we extend will
not override the ones inherited from InputStream/OutputStream.
Now I'll admit that I made my earlier comment a bit quickly and that in the end
it may be simpler/cleaner to make FastByteArray*Stream extends
Input/OutputStream directly and use
{noformat}
InputStream buffer = new FastByteArrayInputStream(bytes);
OutputStream buffer = new FastByteArrayOutputStream(bytes);
{noformat}
We cannot always do that for the OutputStream side because OutputStream doesn't
have the toByteArray() method, but we can use FastByteArrayOutputStream then.
Really my earlier comment was more about avoiding to use FastByteArray*Stream
in more places than strictly necessary.
> 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
>
>
> 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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