Occasional corruption of parquet files , parquet writer might not be calling ParquetFileWriter->end()
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Descripción
We have a high volume streaming service which works most of the time . But off late we have been observing that some of the parquet files written out by write flow are getting corrupted. This is manifested in our reading flow with the following exception
Writer version - 1.6.0 , Reader version - 1.7.0
Caused by: java.lang.RuntimeException: hdfs://Ingest/ingest/jobs/2017-11-30/00-05/part4139 is not a Parquet file. expected magic number at tail [80, 65, 82, 49] but found [-28, -126, 1, 1]
at org.apache.parquet.hadoop.ParquetFileReader.readFooter(ParquetFileReader.java:422)
at org.apache.parquet.hadoop.ParquetFileReader.readFooter(ParquetFileReader.java:385)
at org.apache.parquet.hadoop.ParquetRecordReader.initializeInternalReader(ParquetRecordReader.java:157)
at org.apache.parquet.hadoop.ParquetRecordReader.initialize(ParquetRecordReader.java:140)
at org.apache.spark.rdd.SqlNewHadoopRDD$$anon$1.(SqlNewHadoopRDD.scala:180)
at org.apache.spark.rdd.SqlNewHadoopRDD.compute(SqlNewHadoopRDD.scala:126)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:306)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:270)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:306)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:270)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:306)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:270)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:73)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:41)
at org.apache.spark.scheduler.Task.run(Task.scala:89)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:227)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)```
After looking at the code , i can see that one of the possible causes is/are
1] footer not being serialized in the writer due to end not being called
but we are not seeing any exceptions on the writer.
2] data size - does data size has impact ? There will be cases when row group sizes will be huge as it is activity data of a user
We are using default parquet block size and hdfs block size . Other than upgrading to the latest version and re-test , what are the options we have to debug a issue like this
**Reporter**: [venkata yerubandi](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=raoyvn)
**Note**: *This issue was originally created as [PARQUET-1176](https://issues.apache.org/jira/browse/PARQUET-1176). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*
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Línea de trabajo
Comienza revisando las ubicaciones del stack trace de ParquetFileReader.readFooter, especialmente ParquetFileReader.java:422, e inspecciona la ruta de escritura para comprobar si se llama a ParquetFileWriter->end(). Reproduce la corrupción en el servicio de streaming de alto volumen mientras varías los tamaños de los row-groups y de los bloques HDFS. Se considerará terminado cuando se haya identificado la causa del magic number final ausente y se haya documentado una ruta de depuración o corrección verificada.
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Evaluación
- Stack tecnológico
- java, spark
- Área
- data-engineering
- Tipo de issue
- Error
- Dificultad
- 4/5
- Tiempo estimado
- 3-5 días
- Estado de actividad
- Estancado
- Claridad
- Necesita aclaración
- Aptitud para principiantes
- 25/100