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https://issues.apache.org/jira/browse/HIVE-4423?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13643778#comment-13643778
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Hudson commented on HIVE-4423:
------------------------------
Integrated in Hive-trunk-hadoop2 #179 (See
[https://builds.apache.org/job/Hive-trunk-hadoop2/179/])
HIVE-4423 : Improve RCFile::sync(long) 10x (Gopal V via Ashutosh Chauhan)
(Revision 1476648)
Result = FAILURE
hashutosh :
http://svn.apache.org/viewcvs.cgi/?root=Apache-SVN&view=rev&rev=1476648
Files :
* /hive/trunk/ql/src/java/org/apache/hadoop/hive/ql/io/RCFile.java
> Improve RCFile::sync(long) 10x
> ------------------------------
>
> Key: HIVE-4423
> URL: https://issues.apache.org/jira/browse/HIVE-4423
> Project: Hive
> Issue Type: Improvement
> Environment: Ubuntu LXC (1 SSD, 1 disk, 32 gigs of RAM)
> Reporter: Gopal V
> Assignee: Gopal V
> Priority: Minor
> Labels: optimization
> Fix For: 0.12.0
>
> Attachments: HIVE-4423.patch
>
>
> RCFile::sync(long) takes approx ~1 second everytime it gets called because of
> the inner loops in the function.
> From what was observed with HDFS-4710, single byte reads are an order of
> magnitude slower than larger 512 byte buffer reads.
> Even when disk I/O is buffered to this size, there is overhead due to the
> synchronized read() methods in BlockReaderLocal & RemoteBlockReader classes.
> Removing the readByte() calls in RCFile.sync(long) with a readFully(512 byte)
> call will speed this function >10x.
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