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https://issues.apache.org/jira/browse/HBASE-5074?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13215152#comment-13215152
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Phabricator commented on HBASE-5074:
------------------------------------
mbautin has commented on the revision "[jira] [HBASE-5074] Support checksums in
HBase block cache".
@dhruba: some more comments inline.
INLINE COMMENTS
src/main/java/org/apache/hadoop/hbase/io/hfile/HFileBlock.java:451-452 Assign
headerSize() to a local variable instead of calling it twice.
src/main/java/org/apache/hadoop/hbase/io/hfile/HFileBlock.java:529-530 Call
headerSize() once and store in a local variable.
src/main/java/org/apache/hadoop/hbase/io/hfile/HFileBlock.java:1232 do do ->
do
src/main/java/org/apache/hadoop/hbase/io/hfile/HFileBlock.java:1642-1644
Store and reuse part of the previous error message.
src/main/java/org/apache/hadoop/hbase/io/hfile/HFileBlock.java:1636 Check if
WARN level messages are enabled and only generate the message string in that
case.
src/main/java/org/apache/hadoop/hbase/io/hfile/HFileBlock.java:1848 double
semicolon (does not matter)
src/main/java/org/apache/hadoop/hbase/io/hfile/HFileReaderV2.java:424 What if
istream != istreamNoFsChecksum but istreamNoFsChecksum == null?
src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java:3610-3612 Not
sure how this is related to HBase-level checksum checking
src/main/java/org/apache/hadoop/hbase/regionserver/Store.java:265 Make this
conf key a constant in HConstants
src/main/java/org/apache/hadoop/hbase/regionserver/Store.java:275 conf key ->
HConstants
src/main/java/org/apache/hadoop/hbase/util/ChecksumType.java:40-43 This is
unnecessary because the default toString would do the same.
src/main/java/org/apache/hadoop/hbase/util/ChecksumType.java:57-60 This is
unnecessary because the default toString would do the same.
src/main/java/org/apache/hadoop/hbase/util/ChecksumType.java:103-106 This is
unnecessary because the default toString would do the same.
src/main/java/org/apache/hadoop/hbase/util/ChecksumType.java:143-144 It looks
like toString would to this.
src/main/java/org/apache/hadoop/hbase/util/ChecksumType.java:179 Would not
the built-in enum method valueOf do what this function is doing?
src/test/java/org/apache/hadoop/hbase/io/hfile/TestHFileBlockCompatibility.java:1
This file still seems to contain a lot of copy-and-paste from TestHFileBlock.
Are you planning to address that?
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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