Fangshi Li created SPARK-23815:
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Summary: Spark writer dynamic partition overwrite mode fails to
write output on multi level partition
Key: SPARK-23815
URL: https://issues.apache.org/jira/browse/SPARK-23815
Project: Spark
Issue Type: Bug
Components: Spark Core
Affects Versions: 2.3.0
Reporter: Fangshi Li
Spark introduced new writer mode to overwrite only related partitions in
SPARK-20236. While we are using this feature in our production cluster, we
found a bug when writing multi-level partitions on HDFS.
A simple test case to reproduce this issue:
val df = Seq(("1","2","3")).toDF("col1", "col2","col3")
df.write.partitionBy("col1","col2").mode("overwrite").save("/my/hdfs/location")
If HDFS location "/my/hdfs/location" does not exist, there will be no output.
This seems to be caused by the job commit change in SPARK-20236 in
HadoopMapReduceCommitProtocol.
In the commit job process, the output has been written into staging dir
/my/hdfs/location/.spark-staging.xxx/col1=1/col2=2, and then the code calls
fs.rename to rename /my/hdfs/location/.spark-staging.xxx/col1=1/col2=2 to
/my/hdfs/location/col1=1/col2=2. However, in our case the operation will fail
on HDFS because /my/hdfs/location/col1=1 does not exists. HDFS rename can not
create directory for more than one level.
This does not happen in unit test covered with SPARK-20236 with local file
system.
We are proposing a fix. When cleaning current partition dir
/my/hdfs/location/col1=1/col2=2 before the rename op, if the delete op fails
(because /my/hdfs/location/col1=1/col2=2 may not exist), we call mkdirs op to
create the parent dir /my/hdfs/location/col1=1 (if the parent dir does not
exist) so the following rename op can succeed.
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