Sergey Shelukhin created HIVE-15178:
---------------------------------------
Summary: ORC stripe merge may produce many MR jobs and no merge if
split size is small
Key: HIVE-15178
URL: https://issues.apache.org/jira/browse/HIVE-15178
Project: Hive
Issue Type: Bug
Reporter: Sergey Shelukhin
orc_createas1
logs the following:
{noformat}
2016-11-10T13:38:54,366 INFO [LocalJobRunner Map Task Executor #0]
mapred.MapTask: Processing split:
Paths:/Users/sergey/git/hivegit2/itests/qtest/target/warehouse/.hive-staging_hive_2016-11-10_13-38-52_334_1323113125332102866-1/-ext-10004/000001_0:2400+100InputFormatClass:
org.apache.hadoop.hive.ql.io.orc.OrcFileStripeMergeInputFormat
2016-11-10T13:38:54,373 INFO [LocalJobRunner Map Task Executor #0]
mapred.MapTask: Processing split:
Paths:/Users/sergey/git/hivegit2/itests/qtest/target/warehouse/.hive-staging_hive_2016-11-10_13-38-52_334_1323113125332102866-1/-ext-10004/000001_0:2500+100InputFormatClass:
org.apache.hadoop.hive.ql.io.orc.OrcFileStripeMergeInputFormat
2016-11-10T13:38:54,380 INFO [LocalJobRunner Map Task Executor #0]
mapred.MapTask: Processing split:
Paths:/Users/sergey/git/hivegit2/itests/qtest/target/warehouse/.hive-staging_hive_2016-11-10_13-38-52_334_1323113125332102866-1/-ext-10004/000001_0:2600+100InputFormatClass:
org.apache.hadoop.hive.ql.io.orc.OrcFileStripeMergeInputFormat
2016-11-10T13:38:54,387 INFO [LocalJobRunner Map Task Executor #0]
mapred.MapTask: Processing split:
Paths:/Users/sergey/git/hivegit2/itests/qtest/target/warehouse/.hive-staging_hive_2016-11-10_13-38-52_334_1323113125332102866-1/-ext-10004/000001_0:2700+100InputFormatClass:
org.apache.hadoop.hive.ql.io.orc.OrcFileStripeMergeInputFormat
...
{noformat}
It tries to merge 2 files, but instead ends up running tons of MR tasks for
every 100 bytes and produces 2 files again (I assume most tasks don't produce
the files because the stripes are invalid).
{noformat}
2016-11-10T13:38:53,985 INFO [LocalJobRunner Map Task Executor #0]
OrcFileMergeOperator: Merged stripe from file
pfile:/Users/sergey/git/hivegit2/itests/qtest/target/warehouse/.hive-staging_hive_2016-11-10_13-38-52_334_1323113125332102866-1/-ext-10004/000000_0
[ offset : 3 length: 2770 row: 500 ]
2016-11-10T13:38:53,995 INFO [LocalJobRunner Map Task Executor #0]
exec.AbstractFileMergeOperator: renamed path
pfile:/Users/sergey/git/hivegit2/itests/qtest/target/warehouse/.hive-staging_hive_2016-11-10_13-38-52_334_1323113125332102866-1/_task_tmp.-ext-10002/_tmp.000002_0
to
pfile:/Users/sergey/git/hivegit2/itests/qtest/target/warehouse/.hive-staging_hive_2016-11-10_13-38-52_334_1323113125332102866-1/_tmp.-ext-10002/000002_0
. File size is 2986
2016-11-10T13:38:54,206 INFO [LocalJobRunner Map Task Executor #0]
OrcFileMergeOperator: Merged stripe from file
pfile:/Users/sergey/git/hivegit2/itests/qtest/target/warehouse/.hive-staging_hive_2016-11-10_13-38-52_334_1323113125332102866-1/-ext-10004/000001_0
[ offset : 3 length: 2770 row: 500 ]
2016-11-10T13:38:54,215 INFO [LocalJobRunner Map Task Executor #0]
exec.AbstractFileMergeOperator: renamed path
pfile:/Users/sergey/git/hivegit2/itests/qtest/target/warehouse/.hive-staging_hive_2016-11-10_13-38-52_334_1323113125332102866-1/_task_tmp.-ext-10002/_tmp.000030_0
to
pfile:/Users/sergey/git/hivegit2/itests/qtest/target/warehouse/.hive-staging_hive_2016-11-10_13-38-52_334_1323113125332102866-1/_tmp.-ext-10002/000030_0
. File size is 2986
{noformat}
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
