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https://issues.apache.org/jira/browse/HBASE-20674?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16500854#comment-16500854
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Xiao Chen commented on HBASE-20674:
-----------------------------------
Thanks [~mdrob] for the ping.
The hadoop implementation of
[ChecksumFileSystem|https://github.com/apache/hadoop/blob/trunk/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/ChecksumFileSystem.java#L50-L51]
does not require parity of these 2 options, so one can choose to only enable
it on write and disable it on read. (Actually, the {{writeChecksum}} option was
added later by HADOOP-8042)
> clean up short circuit read logic and docs
> ------------------------------------------
>
> Key: HBASE-20674
> URL: https://issues.apache.org/jira/browse/HBASE-20674
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 2.0.0
> Reporter: Mike Drob
> Assignee: Mike Drob
> Priority: Major
> Attachments: HBASE-20674.patch, HBASE-20674.v2.patch
>
>
> Mailing list discussion at
> https://lists.apache.org/thread.html/f6f73df0ceae29f762f9b9088e3ffd0bf8f109d3dd692df100bf4fd6@%3Cdev.hbase.apache.org%3E
> There are several inconsistencies between how our docs claim we do things and
> how we actually do things.
> There are two docs sections that attempt to address how SCR should work.
> dfs.client.read.shortcircuit.skip.checksum is advised to set to true, but our
> code in separate places ignores it and then later sets it to true anyway.
> CommonFSUtils and FSUtils duplicate code related to SCR setup.
> There is a workaround in HFileSystem for a bug that's been fixed in all
> versions of hadoop that we support. (HADOOP-9307)
> We suggest setting dfs.client.read.shortcircuit.buffer.size to a value that
> is very close to what we'd set it to anyway, without clearly explaining why
> this is important.
> There are other properties that we claim are important, but we don't offer
> any suggestions or explanations.
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