[stable branch] Person Serializer failing with `Mkdirs failed to create` exception

[arvindshmicrosoft]

Due to open items like ldbc/ldbc_snb_datagen_spark#206 with dev, I am currently running with the stable branch (commit hash d6620b9) on a 8-node Hadoop cluster (Hadoop 3.3.0, Centos 7.5, Java 8). There seems to be some weird issue with the output folders: initially, the data generation seemed to succeed, but unfortunately the dynamic folder did not seem to have been produced. After trying some things, I thought I'd set ldbc.snb.datagen.serializer.outputDir to /ldbc_dataset/sf1, the generation consistently fails at the Person Serializer job, with the below stack. I have checked Hadoop permissions, ownership and groups - nothing helped.

Do you see anything here which I can do?

2020-10-15 19:02:00,714 INFO mapreduce.Job: Task Id : attempt_1602777928494_0089_r_000000_1, Status : FAILED
Error: java.lang.RuntimeException: java.io.IOException: Mkdirs failed to create /ldbc_dataset/sf1/social_network/dynamic (exists=false, cwd=file:/mydata4/hadoop/yarn/local/usercache/centos/appcache/application_1602777928494_0089/container_1602777928494_0089_01_000004)
        at ldbc.snb.datagen.hadoop.serializer.HadoopPersonSortAndSerializer$HadoopDynamicPersonSerializerReducer.setup(HadoopPersonSortAndSerializer.java:97)
        at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:168)
        at org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:628)
        at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:390)
        at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:178)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:422)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1845)
        at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:172)
Caused by: java.io.IOException: Mkdirs failed to create /ldbc_dataset/sf1/social_network/dynamic (exists=false, cwd=file:/mydata4/hadoop/yarn/local/usercache/centos/appcache/application_1602777928494_0089/container_1602777928494_0089_01_000004)
        at org.apache.hadoop.fs.ChecksumFileSystem.create(ChecksumFileSystem.java:473)
        at org.apache.hadoop.fs.ChecksumFileSystem.create(ChecksumFileSystem.java:458)
        at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:1164)
        at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:1144)
        at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:1103)
        at ldbc.snb.datagen.hadoop.writer.HdfsWriter.<init>(HdfsWriter.java:66)
        at ldbc.snb.datagen.hadoop.writer.HdfsCsvWriter.<init>(HdfsCsvWriter.java:49)
        at ldbc.snb.datagen.serializer.snb.csv.CsvSerializer.initialize(CsvSerializer.java:23)
        at ldbc.snb.datagen.serializer.LdbcSerializer.initialize(LdbcSerializer.java:20)
        at ldbc.snb.datagen.hadoop.serializer.HadoopPersonSortAndSerializer$HadoopDynamicPersonSerializerReducer.setup(HadoopPersonSortAndSerializer.java:91)
        ... 8 more

[szarnyasg]

Unfortunately, I was not able to reproduce / solve this issue.

A possible workaround is to run the generation on a single node (pseudo-distributed Hadoop cluster). This is very slow as it only uses a single thread but it doesn't crash.

Using 1 TB memory is sufficient to generate data sets up to SF3,000 (see the new data set at ldbc/ldbc_snb_docs#251).

I'm closing this issue as it's unlikely to be resolved in the future due to a lack of attention on this data generator.