I am running Hive in EMR and since upgrading to 0.11 from 0.8.1.8 I have been
getting NullPointerExceptions (NPE) for certain queries in our staging
environment. Only difference between stage and production is the amount of
traffic we get so the data set is much smaller. We are not using any custom
code.
I have greatly simplified the query down to the bare minimum that will cause
the error:
SELECT
count(DISTINCT ag.adGroupGuid) as groups,
count(DISTINCT av.adViewGuid) as ads,
count(DISTINCT ac.adViewGuid) as uniqueClicks
FROM
adgroup ag
INNER JOIN adview av ON av.adGroupGuid = ag.adGroupGuid
LEFT OUTER JOIN adclick ac ON ac.adViewGuid = av.adViewGuid
This will return the following before any Map Reduce jobs start:
FAILED: NullPointerException null
Looking in the hive log at /mnt/var/log/apps/hive_0110.log and scanning, I see
this error:
2013-09-03 18:09:19,796 INFO org.apache.hadoop.hive.ql.exec.Utilities
(Utilities.java:getInputSummary(1889)) - Cache Content Summary for
s3://{ourS3Bucket}/hive/data/stage/adgroup/year=2013/month=08/day=29 length:
94324 file count: 20 directory count: 1
2013-09-03 18:09:19,796 INFO org.apache.hadoop.hive.ql.exec.Utilities
(Utilities.java:getInputSummary(1889)) - Cache Content Summary for
s3://{ourS3Bucket}/hive/data/stage/adview/year=2013/month=08/day=30 length:
142609 file count: 21 directory count: 1
2013-09-03 18:09:19,796 INFO org.apache.hadoop.hive.ql.exec.Utilities
(Utilities.java:getInputSummary(1889)) - Cache Content Summary for
s3://{ourS3Bucket}/hive/data/stage/adgroup/year=2013/month=08/day=30 length:
65519 file count: 21 directory count: 1
2013-09-03 18:09:19,796 INFO org.apache.hadoop.hive.ql.exec.Utilities
(Utilities.java:getInputSummary(1889)) - Cache Content Summary for
s3://{ourS3Bucket}/hive/data/stage/adview/year=2013/month=08/day=29 length:
205096 file count: 20 directory count: 1
2013-09-03 18:09:19,800 INFO
org.apache.hadoop.hive.ql.optimizer.physical.MetadataOnlyOptimizer
(MetadataOnlyOptimizer.java:dispatch(267)) - Looking for table scans where
optimization is applicable
2013-09-03 18:09:19,801 INFO
org.apache.hadoop.hive.ql.optimizer.physical.MetadataOnlyOptimizer
(MetadataOnlyOptimizer.java:dispatch(301)) - Found 0 metadata only table scans
2013-09-03 18:09:19,801 INFO
org.apache.hadoop.hive.ql.optimizer.physical.MetadataOnlyOptimizer
(MetadataOnlyOptimizer.java:dispatch(267)) - Looking for table scans where
optimization is applicable
2013-09-03 18:09:19,801 INFO
org.apache.hadoop.hive.ql.optimizer.physical.MetadataOnlyOptimizer
(MetadataOnlyOptimizer.java:dispatch(301)) - Found 1 metadata only table scans
2013-09-03 18:09:19,801 ERROR org.apache.hadoop.hive.ql.Driver
(SessionState.java:printError(386)) - FAILED: NullPointerException null
java.lang.NullPointerException
at
org.apache.hadoop.hive.ql.optimizer.physical.MetadataOnlyOptimizer$MetadataOnlyTaskDispatcher.dispatch(MetadataOnlyOptimizer.java:308)
at
org.apache.hadoop.hive.ql.lib.DefaultGraphWalker.dispatch(DefaultGraphWalker.java:87)
at
org.apache.hadoop.hive.ql.lib.DefaultGraphWalker.walk(DefaultGraphWalker.java:124)
at
org.apache.hadoop.hive.ql.lib.DefaultGraphWalker.startWalking(DefaultGraphWalker.java:101)
at
org.apache.hadoop.hive.ql.optimizer.physical.MetadataOnlyOptimizer.resolve(MetadataOnlyOptimizer.java:175)
at
org.apache.hadoop.hive.ql.optimizer.physical.PhysicalOptimizer.optimize(PhysicalOptimizer.java:79)
at
org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.genMapRedTasks(SemanticAnalyzer.java:8426)
at
org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.analyzeInternal(SemanticAnalyzer.java:8789)
at
org.apache.hadoop.hive.ql.parse.BaseSemanticAnalyzer.analyze(BaseSemanticAnalyzer.java:278)
at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:433)
at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:337)
at org.apache.hadoop.hive.ql.Driver.run(Driver.java:902)
at
org.apache.hadoop.hive.cli.CliDriver.processLocalCmd(CliDriver.java:310)
at org.apache.hadoop.hive.cli.CliDriver.processCmd(CliDriver.java:231)
at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:466)
at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:819)
at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:674)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.util.RunJar.main(RunJar.java:187)
The same error also happens if I do an INNER JOIN to adclick, FYI.
I have checked that there are not any null values for any of the columns
referenced in the query.
Making almost any changes to the query results it in successfully running.
Here are some I have tried:
Removed JOIN to adgroup:
SELECT
count(DISTINCT av.adViewGuid) as ads,
count(DISTINCT ac.adViewGuid) as uniqueClicks
FROM
adview av
LEFT OUTER JOIN adclick ac ON ac.adViewGuid = av.adViewGuid;
WORKS:
561 6
Removed JOIN to adclick:
SELECT
count(DISTINCT ag.adGroupGuid) as groups,
count(DISTINCT av.adViewGuid) as ads
FROM
adgroup ag
INNER JOIN adview av ON av.adGroupGuid = ag.adGroupGuid;
WORKS:
543 561
Removing DISTINCT from any of the 3 counts
SELECT
count(DISTINCT ag.adGroupGuid) as groups,
count(DISTINCT av.adViewGuid) as ads,
count(ac.adViewGuid) as uniqueClicks
FROM
adgroup ag
INNER JOIN adview av ON av.adGroupGuid = ag.adGroupGuid
LEFT OUTER JOIN adclick ac ON ac.adViewGuid = av.adViewGuid;
WORKS:
543 561 7
SELECT
count(ag.adGroupGuid) as groups,
count(DISTINCT av.adViewGuid) as ads,
count(DISTINCT ac.adViewGuid) as uniqueClicks
FROM
adgroup ag
INNER JOIN adview av ON av.adGroupGuid = ag.adGroupGuid
LEFT OUTER JOIN adclick ac ON ac.adViewGuid = av.adViewGuid;
WORKS:
562 561 6
SELECT
count(DISTINCT ag.adGroupGuid) as groups,
count(av.adViewGuid) as ads,
count(DISTINCT ac.adViewGuid) as uniqueClicks
FROM
adgroup ag
INNER JOIN adview av ON av.adGroupGuid = ag.adGroupGuid
LEFT OUTER JOIN adclick ac ON ac.adViewGuid = av.adViewGuid;
WORKS:
543 562 6
I am not exactly sure what to do next. Thoughts?
Nate
