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https://issues.apache.org/jira/browse/HBASE-5074?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13215115#comment-13215115
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Phabricator commented on HBASE-5074:
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mbautin has commented on the revision "[jira] [HBASE-5074] Support checksums in
HBase block cache".
@dhruba: going through the diff once again. Since you've updated the
revision, submitting existing comments against the previous version, and
continuing with the new version.
INLINE COMMENTS
src/main/java/org/apache/hadoop/hbase/io/hfile/ChecksumUtil.java:131
Misspelling: "Minimun" -> Minimum
src/main/java/org/apache/hadoop/hbase/fs/HFileSystem.java:44-45 Can these two
be made final too?
src/main/java/org/apache/hadoop/hbase/io/hfile/ChecksumUtil.java:145
s/chuck/chunk/
src/main/java/org/apache/hadoop/hbase/io/hfile/AbstractHFileReader.java:48
Fix javadoc: do do -> do
src/main/java/org/apache/hadoop/hbase/io/hfile/ChecksumUtil.java:38 Make this
final, rename to DUMMY_VALUE, because this is a constant, and make the length a
factor of 16 to take advantage of alignment.
src/main/java/org/apache/hadoop/hbase/io/hfile/FixedFileTrailer.java:532
s/manor/major/
src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java:157 This comment is
misleading. This is not something that defaults to the 16 K, but the default
value itself. I think this should say something about how a non-default value
is specified.
src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java:265-271 The
additional constructor should not be needed when
https://issues.apache.org/jira/browse/HBASE-5442 goes in.
src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java:409 Is it possible
to obtain the filesystem from the input stream rather than pass it as an
additional parameter? Or is the underlying filesystem of the input stream a
regular one, as opposed to an HFileSystem?
REVISION DETAIL
https://reviews.facebook.net/D1521
> support checksums in HBase block cache
> --------------------------------------
>
> Key: HBASE-5074
> URL: https://issues.apache.org/jira/browse/HBASE-5074
> Project: HBase
> Issue Type: Improvement
> Components: regionserver
> Reporter: dhruba borthakur
> Assignee: dhruba borthakur
> Attachments: D1521.1.patch, D1521.1.patch, D1521.2.patch,
> D1521.2.patch, D1521.3.patch, D1521.3.patch, D1521.4.patch, D1521.4.patch,
> D1521.5.patch, D1521.5.patch, D1521.6.patch, D1521.6.patch, D1521.7.patch,
> D1521.7.patch, D1521.8.patch, D1521.8.patch, D1521.9.patch, D1521.9.patch
>
>
> The current implementation of HDFS stores the data in one block file and the
> metadata(checksum) in another block file. This means that every read into the
> HBase block cache actually consumes two disk iops, one to the datafile and
> one to the checksum file. This is a major problem for scaling HBase, because
> HBase is usually bottlenecked on the number of random disk iops that the
> storage-hardware offers.
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