Chun Chen created HIVE-6309:
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Summary: Hive incorrectly removes TaskAttempt output files if
MRAppMaster fails once
Key: HIVE-6309
URL: https://issues.apache.org/jira/browse/HIVE-6309
Project: Hive
Issue Type: Bug
Environment: hadoop 2.2
Reporter: Chun Chen
Assignee: Chun Chen
Priority: Critical
Fix For: 0.13.0
We recently upgrade to hadoop2.2 and sometimes find some tables lost several
data files than yesterday after a mid night ETL process. We find that these
MapReduce jobs which generate the partial tables have something in common that
the MRAppMaster of which had failed once and the tables all left only a single
data file 000000_1000.
The following log in hive.log give us some clues of what's going on with the
incorrectly deleted data files.
{code}
$ grep 'hive_2014-01-24_12-33-18_507_6790415670781610350' hive.log
2014-01-24 12:52:43,140 WARN exec.Utilities
(Utilities.java:removeTempOrDuplicateFiles(1535)) - Duplicate taskid file
removed:
hdfs://hadoop00.lf.sankuai.com:9000/tmp/hive-scratch/hive-sankuai/hive_2014-01-24_12-33-18_507_6790415670781610350/_tmp.-ext-10000.intermediate/000001_1000
with length 824627293. Existing file:
hdfs://hadoop00.lf.sankuai.com:9000/tmp/hive-scratch/hive-sankuai/hive_2014-01-24_12-33-18_507_6790415670781610350/_tmp.-ext-10000.intermediate/000000_1000
with length 824860643
2014-01-24 12:52:43,142 WARN exec.Utilities
(Utilities.java:removeTempOrDuplicateFiles(1535)) - Duplicate taskid file
removed:
hdfs://hadoop00.lf.sankuai.com:9000/tmp/hive-scratch/hive-sankuai/hive_2014-01-24_12-33-18_507_6790415670781610350/_tmp.-ext-10000.intermediate/000002_1000
with length 824681826. Existing file:
hdfs://hadoop00.lf.sankuai.com:9000/tmp/hive-scratch/hive-sankuai/hive_2014-01-24_12-33-18_507_6790415670781610350/_tmp.-ext-10000.intermediate/000000_1000
with length 824860643
2014-01-24 12:52:43,149 WARN exec.Utilities
(Utilities.java:removeTempOrDuplicateFiles(1535)) - Duplicate taskid file
removed:
hdfs://hadoop00.lf.sankuai.com:9000/tmp/hive-scratch/hive-sankuai/hive_2014-01-24_12-33-18_507_6790415670781610350/_tmp.-ext-10000.intermediate/000003_1000
with length 824830450. Existing file:
hdfs://hadoop00.lf.sankuai.com:9000/tmp/hive-scratch/hive-sankuai/hive_2014-01-24_12-33-18_507_6790415670781610350/_tmp.-ext-10000.intermediate/000000_1000
with length 824860643
2014-01-24 12:52:43,151 WARN exec.Utilities
(Utilities.java:removeTempOrDuplicateFiles(1535)) - Duplicate taskid file
removed:
hdfs://hadoop00.lf.sankuai.com:9000/tmp/hive-scratch/hive-sankuai/hive_2014-01-24_12-33-18_507_6790415670781610350/_tmp.-ext-10000.intermediate/000004_1000
with length 824753882. Existing file:
hdfs://hadoop00.lf.sankuai.com:9000/tmp/hive-scratch/hive-sankuai/hive_2014-01-24_12-33-18_507_6790415670781610350/_tmp.-ext-10000.intermediate/000000_1000
with length 824860643
{code}
We find that it's because nextAttemptNumber in hadoop2.2 is bigger than 1000
and hive doesn't not correctly extract task id from filename. See the following
code in org.apache.hadoop.mapreduce.v2.app.job.impl.TaskImpl.java
and ql/src/java/org/apache/hadoop/hive/ql/exec/Utilities.java
{code}
// All the new TaskAttemptIDs are generated based on MR
// ApplicationAttemptID so that attempts from previous lives don't
// over-step the current one. This assumes that a task won't have more
// than 1000 attempts in its single generation, which is very reasonable.
nextAttemptNumber = (appAttemptId - 1) * 1000;
/**
* The first group will contain the task id. The second group is the
optional extension. The file
* name looks like: "0_0" or "0_0.gz". There may be a leading prefix (tmp_).
Since getTaskId() can
* return an integer only - this should match a pure integer as well. {1,3}
is used to limit
* matching for attempts #'s 0-999.
*/
private static final Pattern FILE_NAME_TO_TASK_ID_REGEX =
Pattern.compile("^.*?([0-9]+)(_[0-9]{1,3})?(\\..*)?$");
{code}
And with the bellow reasons, extract this value for attempt numbers >= 1000 :
{code}
>>> re.match("^.*?([0-9]+)(_[0-9])?(\\..*)?$", 'part-r-000000_2').group(1)
'000000'
>>> re.match("^.*?([0-9]+)(_[0-9])?(\\..*)?$", 'part-r-000000_1001').group(1)
'1001'
{code}
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