apache / apache/parquet-java

Cannot read parquet file that was generated from nanoparquet

Open
#3,043 1 comment 0 reactions 0 assignees View on GitHub
Type: bug
Dominant language
Java
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Merged PRs (30d)
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Description

### Describe the bug, including details regarding any error messages, version, and platform.

When trying to use `MessageColumnIO` to get a record reader, the following error occurs:
```
Exception in thread "main" java.lang.UnsupportedOperationException
at org.apache.parquet.column.values.ValuesReader.readInteger(ValuesReader.java:178)
at org.apache.parquet.column.impl.ColumnReaderBase$ValuesReaderIntIterator.nextInt(ColumnReaderBase.java:830)
at org.apache.parquet.column.impl.ColumnReaderBase.checkRead(ColumnReaderBase.java:663)
at org.apache.parquet.column.impl.ColumnReaderBase.consume(ColumnReaderBase.java:801)
at org.apache.parquet.column.impl.ColumnReaderImpl.consume(ColumnReaderImpl.java:30)
at org.apache.parquet.column.impl.ColumnReaderImpl.(ColumnReaderImpl.java:43)
at org.apache.parquet.column.impl.ColumnReadStoreImpl.getColumnReader(ColumnReadStoreImpl.java:80)
at org.apache.parquet.io.RecordReaderImplementation.(RecordReaderImplementation.java:282)
at org.apache.parquet.io.MessageColumnIO$1.visit(MessageColumnIO.java:141)
at org.apache.parquet.io.MessageColumnIO$1.visit(MessageColumnIO.java:105)
at org.apache.parquet.filter2.compat.FilterCompat$NoOpFilter.accept(FilterCompat.java:180)
at org.apache.parquet.io.MessageColumnIO.getRecordReader(MessageColumnIO.java:105)
```

I expected that this would work. Pyarrow for example can read the file.

Sample file can be found here:

[mtcars_np.zip](https://github.com/user-attachments/files/17649331/mtcars_np.zip)

Nanoparquet can be found here:

https://github.com/r-lib/nanoparquet

Version: 1.14.3
Platform: Linux

### Component(s)

Core

Contributor guide

No contributing guide indexed for this repository

Research direction

Start with the stack trace at org.apache.parquet.column.values.ValuesReader.readInteger and the ColumnReaderBase integer-reading path, using the linked mtcars_np.zip file as the reproduction case. Inspect the file's encoding metadata and compare it with what parquet-java 1.14.3 expects; done means MessageColumnIO can read the nanoparquet-generated file without UnsupportedOperationException.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
data-engineering
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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