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Posted to issues@spark.apache.org by "Reynold Xin (JIRA)" <ji...@apache.org> on 2016/08/10 19:18:20 UTC
[jira] [Commented] (SPARK-16975) Spark-2.0.0 unable to infer schema
for parquet data written by Spark-1.6.2
[ https://issues.apache.org/jira/browse/SPARK-16975?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15415823#comment-15415823 ]
Reynold Xin commented on SPARK-16975:
-------------------------------------
cc [~dongjoon] do you have time to look into this?
> Spark-2.0.0 unable to infer schema for parquet data written by Spark-1.6.2
> --------------------------------------------------------------------------
>
> Key: SPARK-16975
> URL: https://issues.apache.org/jira/browse/SPARK-16975
> Project: Spark
> Issue Type: Bug
> Components: Input/Output
> Affects Versions: 2.0.0
> Environment: Ubuntu Linux 14.04
> Reporter: immerrr again
> Labels: parquet
>
> Spark-2.0.0 seems to have some problems reading a parquet dataset generated by 1.6.2.
> {code}
> In [80]: spark.read.parquet('/path/to/data')
> ...
> AnalysisException: u'Unable to infer schema for ParquetFormat at /path/to/data. It must be specified manually;'
> {code}
> The dataset is ~150G and partitioned by _locality_code column. None of the partitions are empty. I have narrowed the failing dataset to the first 32 partitions of the data:
> {code}
> In [82]: spark.read.parquet(*subdirs[:32])
> ...
> AnalysisException: u'Unable to infer schema for ParquetFormat at /path/to/data/_locality_code=AQ,/path/to/data/_locality_code=AI. It must be specified manually;'
> {code}
> Interestingly, it works OK if you remove any of the partitions from the list:
> {code}
> In [83]: for i in range(32): spark.read.parquet(*(subdirs[:i] + subdirs[i+1:32]))
> {code}
> Another strange thing is that the schemas for the first and the last 31 partitions of the subset are identical:
> {code}
> In [84]: spark.read.parquet(*subdirs[:31]).schema.fields == spark.read.parquet(*subdirs[1:32]).schema.fields
> Out[84]: True
> {code}
> Which got me interested and I tried this:
> {code}
> In [87]: spark.read.parquet(*([subdirs[0]] * 32))
> ...
> AnalysisException: u'Unable to infer schema for ParquetFormat at /path/to/data/_locality_code=AQ,/path/to/data/_locality_code=AQ. It must be specified manually;'
> In [88]: spark.read.parquet(*([subdirs[15]] * 32))
> ...
> AnalysisException: u'Unable to infer schema for ParquetFormat at /path/to/data/_locality_code=AX,/path/to/data/_locality_code=AX. It must be specified manually;'
> In [89]: spark.read.parquet(*([subdirs[31]] * 32))
> ...
> AnalysisException: u'Unable to infer schema for ParquetFormat at /path/to/data/_locality_code=BE,/path/to/data/_locality_code=BE. It must be specified manually;'
> {code}
> If I read the first partition, save it in 2.0 and try to read in the same manner, everything is fine:
> {code}
> In [100]: spark.read.parquet(subdirs[0]).write.parquet('spark-2.0-test')
> 16/08/09 11:03:37 WARN ParquetRecordReader: Can not initialize counter due to context is not a instance of TaskInputOutputContext, but is org.apache.hadoop.mapreduce.task.TaskAttemptContextImpl
> In [101]: df = spark.read.parquet(*(['spark-2.0-test'] * 32))
> {code}
> I have originally posted it to user mailing list, but with the last discoveries this clearly seems like a bug.
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