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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/10795/
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Review request for hive, Ashutosh Chauhan and Gunther Hagleitner.
Description
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Speed up RCFile::sync() by reading large blocks of data from HDFS rather than
using readByte() on the input stream.
This improves the loop behaviour and reduces the number of calls on the
synchronized read() methods within HDFS, resulting in a 10x performance boost
to this function.
In real time, it converts a call that takes upto a second and brings it below
100ms, by reading 512 byte chunks instead of reading data 1 byte at a time.
This addresses bug HIVE-4423.
https://issues.apache.org/jira/browse/HIVE-4423
Diffs
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ql/src/java/org/apache/hadoop/hive/ql/io/RCFile.java d3d98d0
Diff: https://reviews.apache.org/r/10795/diff/
Testing
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ant test -Dtestcase=TestRCFile -Dmodule=ql
ant test -Dtestcase=TestCliDriver -Dqfile_regex=.*rcfile.* -Dmodule=ql
And benchmarking with count(1) on the store_sales rcfile table at scale=10
before: 43.8, after: 39.5
Thanks,
Gopal V
