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https://issues.apache.org/jira/browse/HADOOP-15033?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16251538#comment-16251538
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Dmitry Chuyko edited comment on HADOOP-15033 at 11/14/17 3:38 PM:
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[~raviprak] I compared partial checksums over random array and byte buffer.
Some more details:
* Over 1000 elements (crc of 0 element, crc of 1 element, crc of 2 elements...).
* Zero and non-zero offset.
* Interpreter, C1, C2 Hotspot compiler.
* OpenJDK 10-internal
* x86_64 and aarch64
CRC32C values required to be equal are equal.
was (Author: dchuyko):
[~raviprak] I compared partial checksums over partial random array and byte
buffer. Some more details:
* Over 1000 elements (crc of 0 element, crc of 1 element...).
* Zero and non-zero offset.
* Interpreter, C1, C2 Hotspot compiler.
* OpenJDK 10-internal
* x86_64 and aarch64
CRC32C values required to be equal are equal.
> Use java.util.zip.CRC32C for Java 9 and above
> ---------------------------------------------
>
> Key: HADOOP-15033
> URL: https://issues.apache.org/jira/browse/HADOOP-15033
> Project: Hadoop Common
> Issue Type: Improvement
> Components: performance, util
> Affects Versions: 3.0.0
> Reporter: Dmitry Chuyko
>
> java.util.zip.CRC32C implementation is available since Java 9.
> https://docs.oracle.com/javase/9/docs/api/java/util/zip/CRC32C.html
> Platform specific assembler intrinsics make it more effective than any pure
> Java implementation.
> Hadoop is compiled against Java 8 but class constructor may be accessible
> with method handle on 9 to instances implementing Checksum in runtime.
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