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Posted to dev@thrift.apache.org by "David Mollitor (Jira)" <ji...@apache.org> on 2020/10/06 18:25:00 UTC

[jira] [Updated] (THRIFT-5288) Move Support for ByteBuffer in TTransport

     [ https://issues.apache.org/jira/browse/THRIFT-5288?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

David Mollitor updated THRIFT-5288:
-----------------------------------
    Summary: Move Support for ByteBuffer in TTransport  (was: Better Support for ByteBuffer in Compact Protocol)

> Move Support for ByteBuffer in TTransport
> -----------------------------------------
>
>                 Key: THRIFT-5288
>                 URL: https://issues.apache.org/jira/browse/THRIFT-5288
>             Project: Thrift
>          Issue Type: Improvement
>            Reporter: David Mollitor
>            Assignee: David Mollitor
>            Priority: Minor
>          Time Spent: 20m
>  Remaining Estimate: 0h
>
> {code:java|title=TCompactProtocol.java}
>   /**
>    * Write a byte array, using a varint for the size.
>    */
>   public void writeBinary(ByteBuffer bin) throws TException {
>     int length = bin.limit() - bin.position();
>     writeBinary(bin.array(), bin.position() + bin.arrayOffset(), length);
>   }
> {code}
> I was working on something with Parquet and this code was causing some issues:
> {code:java}
> java.lang.Exception: java.nio.ReadOnlyBufferException
> 	at org.apache.hadoop.mapred.LocalJobRunner$Job.runTasks(LocalJobRunner.java:462)
> 	at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:522)
> Caused by: java.nio.ReadOnlyBufferException
> 	at java.nio.ByteBuffer.array(ByteBuffer.java:996)
> 	at shaded.parquet.org.apache.thrift.protocol.TCompactProtocol.writeBinary(TCompactProtocol.java:375)
> 	at org.apache.parquet.format.InterningProtocol.writeBinary(InterningProtocol.java:135)
> 	at org.apache.parquet.format.ColumnIndex$ColumnIndexStandardScheme.write(ColumnIndex.java:945)
> 	at org.apache.parquet.format.ColumnIndex$ColumnIndexStandardScheme.write(ColumnIndex.java:820)
> 	at org.apache.parquet.format.ColumnIndex.write(ColumnIndex.java:728)
> 	at org.apache.parquet.format.Util.write(Util.java:372)
> 	at org.apache.parquet.format.Util.writeColumnIndex(Util.java:69)
> 	at org.apache.parquet.hadoop.ParquetFileWriter.serializeColumnIndexes(ParquetFileWriter.java:1087)
> 	at org.apache.parquet.hadoop.ParquetFileWriter.end(ParquetFileWriter.java:1050)
> {code}
> This happens, because not all {{Buffer}} allow for direct access to the backing Array,... for example a ByteBuffer tied to a file does not have an Array. Read-only (immutable) {{ByteBuffer}} do not allow for this kind of access to the array since it could then be modified.
> There are two approaches here:
>  # Assert and throw Exception if the backing array must be allowed for access
>  # Deal natively with the ByteBuffer
> I propose the latter. However, the initial naive I approach I propose is to "deal natively" with the ByteBuffer by making a copy of the contents.



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