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https://issues.apache.org/jira/browse/AVRO-1282?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13641150#comment-13641150
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Scott Carey commented on AVRO-1282:
-----------------------------------
In practice, nearly all JVMs have Unsafe these days (since ~2010) because Doug
Lea's concurrent collections are built on it. However, it is not required, so
we should be prepared to have a fallback. And since each implementation does
not contain all methods, we have to be prepared for that as well.
Perhaps we should support reading a System property to disable use? Perhaps if
"avro.disable.unsafe" exists, we fall back to plain reflection? Then we can
run tests that simulate what happens when it fails to find Unsafe or one of the
expected methods by adding "-Davro.disable.unsafe". This also serves as a
work-around if there are other unexpected consequences.
> Make use of the sun.misc.Unsafe class during serialization if a JDK supports
> it
> -------------------------------------------------------------------------------
>
> Key: AVRO-1282
> URL: https://issues.apache.org/jira/browse/AVRO-1282
> Project: Avro
> Issue Type: Improvement
> Components: java
> Affects Versions: 1.7.4
> Reporter: Leo Romanoff
> Priority: Minor
> Attachments: avro-1282-v1.patch, avro-1282-v2.patch,
> avro-1282-v3.patch, avro-1282-v4.patch, avro-1282-v5.patch,
> avro-1282-v6.patch, avro-1282-v7.patch, avro-1282-v8.patch
>
>
> Unsafe can be used to significantly speed up serialization process, if a JDK
> implementation supports java.misc.Unsafe properly. Most JDKs running on PCs
> support it. Some platforms like Android lack a proper support for Unsafe yet.
> There are two possibilities to use Unsafe for serialization:
> 1) Very quick access to the fields of objects. It is way faster than with the
> reflection-based approach using Field.get/set
> 2) Input and Output streams can be using Unsafe to perform very quick
> input/output.
>
> 3) More over, Unsafe makes it possible to serialize to/deserialize from
> off-heap memory directly and very quickly, without any intermediate buffers
> allocated on heap. There is virtually no overhead compared to the usual byte
> arrays.
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