devdanylo opened a new issue, #3150: URL: https://github.com/apache/parquet-java/issues/3150
### Describe the bug, including details regarding any error messages, version, and platform. Hello folks, I'm currently working on removing the `hadoop-common` dependency from the runtime in one of my projects. As part of this process, I need to replace the "Hadoop" codec factory, which relies on certain classes from `hadoop-common`, with a codec factory that exclusively uses classes from `parquet-hadoop`. One potential option is `DirectCodecFactory`, but it comes with a problem. For demonstration purposes, I’m using a simple key-value Snappy-compressed parquet file containing 51,000 records. Here’s a sample of the data: <img width="308" alt="Image" src="https://github.com/user-attachments/assets/bbe7f94c-9904-4bbb-a157-a7d82e9af54f"; /> When attempting to read this file using `DirectCodecFactory`, I encounter two issues: 1. The file fails to read completely. Near the end, it throws an error: `Can't read value in column [key] optional binary key (STRING) = 0 at value 49,534 out of 51,000, 9,534 out of 11,000 in currentPage. Repetition level: 0, definition level: 1.` 2. At record number 40,001, the key and value columns get mixed up, with the key column unexpectedly containing a value. **Note that with the Hadoop codec factory the file can be read without any issues.** Here are tests demonstrating that: ```java package sandbox.parquet.reader; import org.apache.hadoop.conf.Configuration; import org.apache.parquet.bytes.DirectByteBufferAllocator; import org.apache.parquet.column.ParquetProperties; import org.apache.parquet.conf.ParquetConfiguration; import org.apache.parquet.conf.PlainParquetConfiguration; import org.apache.parquet.hadoop.CodecFactory; import org.apache.parquet.hadoop.ParquetReader; import org.apache.parquet.hadoop.api.InitContext; import org.apache.parquet.hadoop.api.ReadSupport; import org.apache.parquet.io.InputFile; import org.apache.parquet.io.LocalInputFile; import org.apache.parquet.io.api.Binary; import org.apache.parquet.io.api.Converter; import org.apache.parquet.io.api.GroupConverter; import org.apache.parquet.io.api.PrimitiveConverter; import org.apache.parquet.io.api.RecordMaterializer; import org.apache.parquet.schema.GroupType; import org.apache.parquet.schema.MessageType; import org.apache.parquet.schema.Type; import org.junit.jupiter.api.Assertions; import org.junit.jupiter.api.Test; import java.nio.file.Path; import java.nio.file.Paths; import java.util.Map; public class ParquetReaderTest { @Test void readParquetFileAndVerifyRecordCount_usingDirectCodeFactory() throws Exception { Path filePath = Paths.get(ClassLoader.getSystemResource("test.parquet").toURI()); int recordCount = 0; try(ParquetReader<String[]> parquetReader = createReaderWithDirectCodeFactory(filePath)) { while (parquetReader.read() != null) { recordCount++; } } Assertions.assertEquals(51_000, recordCount); } @Test void readParquetFileAndVerifyContent_usingDirectCodeFactory() throws Exception { Path filePath = Paths.get(ClassLoader.getSystemResource("test.parquet").toURI()); int recordCount = 0; try(ParquetReader<String[]> parquetReader = createReaderWithHadoopCodeFactory(filePath)) { String[] record; while ((record = parquetReader.read()) != null) { Assertions.assertEquals("key_" + (recordCount + 1), record[0]); Assertions.assertEquals("value_" + (recordCount + 1), record[1]); recordCount++; } } Assertions.assertEquals(51_000, recordCount); } @Test void readParquetFileAndVerifyRecordCount_usingHadoopCodeFactory() throws Exception { Path filePath = Paths.get(ClassLoader.getSystemResource("test.parquet").toURI()); int recordCount = 0; try(ParquetReader<String[]> parquetReader = createReaderWithHadoopCodeFactory(filePath)) { while (parquetReader.read() != null) { recordCount++; } } Assertions.assertEquals(51_000, recordCount); } @Test void readParquetFileAndVerifyContent_usingHadoopCodeFactory() throws Exception { Path filePath = Paths.get(ClassLoader.getSystemResource("test.parquet").toURI()); int recordCount = 0; try(ParquetReader<String[]> parquetReader = createReaderWithDirectCodeFactory(filePath)) { String[] record; while ((record = parquetReader.read()) != null) { Assertions.assertEquals("key_" + (recordCount + 1), record[0]); Assertions.assertEquals("value_" + (recordCount + 1), record[1]); recordCount++; } } Assertions.assertEquals(51_000, recordCount); } private ParquetReader<String[]> createReaderWithDirectCodeFactory(Path file) throws Exception { return new ParquetReaderBuilder(new LocalInputFile(file), new PlainParquetConfiguration()) .withCodecFactory(CodecFactory.createDirectCodecFactory(null, DirectByteBufferAllocator.getInstance(), ParquetProperties.DEFAULT_PAGE_SIZE)) .build(); } private ParquetReader<String[]> createReaderWithHadoopCodeFactory(Path file) throws Exception { // the Hadoop codec factory is created in ParquetReadOptions.Builder#build return new ParquetReaderBuilder(new LocalInputFile(file), new PlainParquetConfiguration()) .build(); } static class ParquetReaderBuilder extends ParquetReader.Builder<String[]> { ParquetReaderBuilder(InputFile file, ParquetConfiguration conf) { super(file, conf); } @Override protected ReadSupport<String[]> getReadSupport() { return new TestReadSupport(); } } static class TestReadSupport extends ReadSupport<String[]> { @Override public ReadContext init(InitContext context) { return new ReadContext(context.getFileSchema()); } @Override public RecordMaterializer<String[]> prepareForRead(Configuration configuration, Map<String, String> keyValueMetaData, MessageType fileSchema, ReadContext readContext) { return new TestRecordMaterializer(fileSchema); } @Override public RecordMaterializer<String[]> prepareForRead(ParquetConfiguration configuration, Map<String, String> keyValueMetaData, MessageType fileSchema, ReadContext readContext) { return new TestRecordMaterializer(fileSchema); } } static class TestRecordMaterializer extends RecordMaterializer<String[]> { private final TestRootGroupConverter root; TestRecordMaterializer(MessageType schema) { this.root = new TestRootGroupConverter(schema); } @Override public String[] getCurrentRecord() { return root.getCurrentRecord(); } @Override public GroupConverter getRootConverter() { return root; } } static class TestRootGroupConverter extends GroupConverter { private String[] currentRecord; private final Converter[] converters; TestRootGroupConverter(GroupType schema) { converters = new Converter[schema.getFieldCount()]; for (int i = 0; i < converters.length; i++) { final Type type = schema.getType(i); if (type.isPrimitive()) { converters[i] = new TestPrimitiveConverter(this, i); } else { throw new RuntimeException("Nested records not supported!"); } } } @Override public Converter getConverter(int fieldIndex) { return converters[fieldIndex]; } @Override public void start() { currentRecord = new String[converters.length]; } @Override public void end() { } String[] getCurrentRecord() { return currentRecord; } } static class TestPrimitiveConverter extends PrimitiveConverter { private final TestRootGroupConverter parent; private final int index; TestPrimitiveConverter(TestRootGroupConverter parent, int index) { this.parent = parent; this.index = index; } @Override public void addBinary(Binary value) { parent.getCurrentRecord()[index] = value.toStringUsingUTF8(); } @Override public void addBoolean(boolean value) { throw new UnsupportedOperationException(); } @Override public void addDouble(double value) { throw new UnsupportedOperationException(); } @Override public void addFloat(float value) { throw new UnsupportedOperationException(); } @Override public void addInt(int value) { throw new UnsupportedOperationException(); } @Override public void addLong(long value) { throw new UnsupportedOperationException(); } } } ``` Attaching the parquet file and a demo application: * [test.parquet.zip](https://github.com/user-attachments/files/18718126/test.parquet.zip) * [parquet-reader.zip](https://github.com/user-attachments/files/18718132/parquet-reader.zip) ### Component(s) Core -- This is an automated message from the Apache Git Service. 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