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From "Steve Loughran (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HADOOP-16109) Parquet reading S3AFileSystem causes EOF
Date Mon, 04 Mar 2019 14:32:00 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-16109?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16783422#comment-16783422

Steve Loughran commented on HADOOP-16109:

bq.  Do you know if, say, seeking to a few bytes before the end of CurrentRequest, then reading
past it (when the S3 file does indeed have more to read), also causes an EOF, or does the
stream machinery handle that case correctly?

matt, this is exactly what is being tested for.
Let me do a variant with a seek to just before EOF and some readbyte and read(byte[]) calls
to verify that too.

And yes, a seek for utter completeness

> Parquet reading S3AFileSystem causes EOF
> ----------------------------------------
>                 Key: HADOOP-16109
>                 URL: https://issues.apache.org/jira/browse/HADOOP-16109
>             Project: Hadoop Common
>          Issue Type: Sub-task
>          Components: fs/s3
>    Affects Versions: 2.9.2, 2.8.5, 3.3.0, 3.1.2
>            Reporter: Dave Christianson
>            Assignee: Steve Loughran
>            Priority: Blocker
> When using S3AFileSystem to read Parquet files a specific set of circumstances causes
an  EOFException that is not thrown when reading the same file from local disk
> Note this has only been observed under specific circumstances:
>   - when the reader is doing a projection (will cause it to do a seek backwards and
put the filesystem into random mode)
>  - when the file is larger than the readahead buffer size
>  - when the seek behavior of the Parquet reader causes the reader to seek towards the
end of the current input stream without reopening, such that the next read on the currently
open stream will read past the end of the currently open stream.
> Exception from Parquet reader is as follows:
> {code}
> Caused by: java.io.EOFException: Reached the end of stream with 51 bytes left to read
>  at org.apache.parquet.io.DelegatingSeekableInputStream.readFully(DelegatingSeekableInputStream.java:104)
>  at org.apache.parquet.io.DelegatingSeekableInputStream.readFullyHeapBuffer(DelegatingSeekableInputStream.java:127)
>  at org.apache.parquet.io.DelegatingSeekableInputStream.readFully(DelegatingSeekableInputStream.java:91)
>  at org.apache.parquet.hadoop.ParquetFileReader$ConsecutiveChunkList.readAll(ParquetFileReader.java:1174)
>  at org.apache.parquet.hadoop.ParquetFileReader.readNextRowGroup(ParquetFileReader.java:805)
>  at org.apache.parquet.hadoop.InternalParquetRecordReader.checkRead(InternalParquetRecordReader.java:127)
>  at org.apache.parquet.hadoop.InternalParquetRecordReader.nextKeyValue(InternalParquetRecordReader.java:222)
>  at org.apache.parquet.hadoop.ParquetRecordReader.nextKeyValue(ParquetRecordReader.java:207)
>  at org.apache.flink.api.java.hadoop.mapreduce.HadoopInputFormatBase.fetchNext(HadoopInputFormatBase.java:206)
>  at org.apache.flink.api.java.hadoop.mapreduce.HadoopInputFormatBase.reachedEnd(HadoopInputFormatBase.java:199)
>  at org.apache.flink.runtime.operators.DataSourceTask.invoke(DataSourceTask.java:190)
>  at org.apache.flink.runtime.taskmanager.Task.run(Task.java:711)
>  at java.lang.Thread.run(Thread.java:748)
> {code}
> The following example program generate the same root behavior (sans finding a Parquet
file that happens to trigger this condition) by purposely reading past the already active
readahead range on any file >= 1029 bytes in size.. 
> {code:java}
> final Configuration conf = new Configuration();
> conf.set("fs.s3a.readahead.range", "1K");
> conf.set("fs.s3a.experimental.input.fadvise", "random");
> final FileSystem fs = FileSystem.get(path.toUri(), conf);
> // forward seek reading across readahead boundary
> try (FSDataInputStream in = fs.open(path)) {
>     final byte[] temp = new byte[5];
>     in.readByte();
>     in.readFully(1023, temp); // <-- works
> }
> // forward seek reading from end of readahead boundary
> try (FSDataInputStream in = fs.open(path)) {
>  final byte[] temp = new byte[5];
>  in.readByte();
>  in.readFully(1024, temp); // <-- throws EOFException
> }
> {code}

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