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https://issues.apache.org/jira/browse/HBASE-20674?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16518417#comment-16518417
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Mike Drob commented on HBASE-20674:
-----------------------------------
bq. Any checking done to ensure we still doing checksumming properly?
The logs from TestChecksumWithHdfs.java do show this but I couldn't figure out
how to drive the plumbing deep enough to make assertions against DFS Client's
behavior.
bq. For SCR 'dfs.client.read.shortcircuit.skip.checksum' should this property
be set to 'true' for hbase case because hbase does checksumming internally?
Yea, we automatically set it on the conf in HFileSystem. Are you asking if we
should document that we recommend setting it? I don't think that is necessary
because we can handle it internally instead of placing more burden on the
operator. Or did I misinterpret?
> 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,
> HBASE-20674.v3.patch, HBASE-20674.v4.patch, HBASE-20674.v5.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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