apache/iceberg · error · UncheckedIOException

Failed to create new equality delete writer

Error message

Failed to create new equality delete writer

What it means

RegistryBasedFileWriterFactory.newEqualityDeleteWriter builds an EqualityDeleteWriter through the writer registry; an IOException while creating/opening the equality delete output file is wrapped in UncheckedIOException with this message.

Source

Thrown at data/src/main/java/org/apache/iceberg/data/RegistryBasedFileWriterFactory.java:154

    try {
      FileWriterBuilder<EqualityDeleteWriter<T>, S> builder =
          FormatModelRegistry.equalityDeleteWriteBuilder(deleteFileFormat, inputType, file);
      return builder
          .setAll(properties)
          .setAll(writerProperties)
          .metricsConfig(metricsConfig)
          .schema(equalityDeleteRowSchema)
          .engineSchema(equalityDeleteInputSchema())
          .equalityFieldIds(equalityFieldIds)
          .spec(spec)
          .partition(partition)
          .keyMetadata(keyMetadata)
          .sortOrder(equalityDeleteSortOrder)
          .overwrite()
          .build();
    } catch (IOException e) {
      throw new UncheckedIOException("Failed to create new equality delete writer", e);
    }
  }

  @Override
  public PositionDeleteWriter<T> newPositionDeleteWriter(
      EncryptedOutputFile file, PartitionSpec spec, StructLike partition) {
    EncryptionKeyMetadata keyMetadata = file.keyMetadata();
    Map<String, String> properties = table != null ? table.properties() : ImmutableMap.of();
    MetricsConfig metricsConfig = MetricsConfig.forPositionDelete();

    try {
      FileWriterBuilder<PositionDeleteWriter<T>, ?> builder =
          FormatModelRegistry.positionDeleteWriteBuilder(deleteFileFormat, file);
      return builder
          .setAll(properties)
          .setAll(writerProperties)
          .metricsConfig(metricsConfig)
          .spec(spec)

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Read the wrapped IOException cause to identify the real open failure.
2. Ensure the registry has an EqualityDeleteWriter factory registered for the target format.
3. Verify write credentials and output path for delete files.
4. Match the delete format to one supported by your writer registry (e.g. parquet).

Example fix

// before: only data writers registered
// after: register equality delete writer factory too
registry.addFactory(Parquet.EqualityDeleteWriter.class, new ParquetEqualityDeleteWriterFactory());

// ensure an equality delete writer factory exists for the format
if (registry.factory(Parquet.EqualityDeleteWriter.class) == null) {
  throw new IllegalStateException("No equality delete writer registered");
}

try {
  EqualityDeleteWriter<T> w = factory.newEqualityDeleteWriter(file, spec, partition);
} catch (UncheckedIOException e) {
  throw new RuntimeException("Equality delete writer open failed: " + e.getCause().getMessage(), e.getCause());
}

When it happens

Trigger: Calling newEqualityDeleteWriter(file, spec, partition) when opening the EncryptedOutputFile fails or no registered equality-delete writer exists for the configured format.

Common situations: Custom writer registries missing equality-delete writer mappings; storage auth/path failures on the delete-file output location; format unsupported for equality deletes.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

• Failed to create new data writer
• Failed to create new position delete writer
• Failed to close current writer
• Failed to close encryption manager
• Failed to write json to file: %s

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/cbb1af64d59132aa. Report an issue: GitHub.