apache/iceberg · error · UnsupportedOperationException

Cannot resolve schema for version: ${writeSchemaVersion}

Error message

Cannot resolve schema for version: ${writeSchemaVersion}

What it means

decode reads a one-byte schema version from the key metadata blob and looks it up in StandardKeyMetadata.supportedAvroSchemaVersions(). If the byte does not map to a known write schema, the blob was produced by an incompatible (newer or corrupt) writer and cannot be decoded by this Iceberg version.

Source

Thrown at core/src/main/java/org/apache/iceberg/encryption/KeyMetadataDecoder.java:62

  @Override
  public StandardKeyMetadata decode(InputStream stream, StandardKeyMetadata reuse) {
    byte writeSchemaVersion;

    try {
      writeSchemaVersion = (byte) stream.read();
    } catch (IOException e) {
      throw new UncheckedIOException("Failed to read the version byte", e);
    }

    if (writeSchemaVersion < 0) {
      throw new RuntimeException("Version byte - end of stream reached");
    }

    Schema writeSchema = StandardKeyMetadata.supportedAvroSchemaVersions().get(writeSchemaVersion);

    if (writeSchema == null) {
      throw new UnsupportedOperationException(
          "Cannot resolve schema for version: " + writeSchemaVersion);
    }

    RawDecoder<StandardKeyMetadata> decoder = decoders.get(writeSchemaVersion);

    if (decoder == null) {
      decoder = RawDecoder.create(readSchema, GenericAvroReader::create, writeSchema);

      decoders.put(writeSchemaVersion, decoder);
    }

    return decoder.decode(stream, reuse);
  }
}

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Upgrade to an Iceberg version that supports the key metadata schema version in the blob
2. Verify the metadata bytes are intact and actually StandardKeyMetadata output
3. Rewrite the table's encryption metadata with a compatible Iceberg version

// preflight: peek the first byte and check support
int version = buffer.duplicate().get();
if (!StandardKeyMetadata.supportedAvroSchemaVersions().containsKey((byte) version)) {
  throw new UnsupportedOperationException("Unsupported key metadata version: " + version);
}

try { return StandardKeyMetadata.parse(buffer); }
catch (RuntimeException e) {
  if (e.getMessage().startsWith("Cannot resolve schema for version")) { /* upgrade path */ }
  throw e;
}

When it happens

Trigger: Decoding key metadata whose version byte is not among the supported Avro schema versions — e.g. metadata written by a newer Iceberg release, or corrupted/offset bytes.

Common situations: Opening encrypted tables written by a newer Iceberg version with an older client; byte corruption in stored metadata; passing non-key-metadata bytes to the decoder.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• Failed to read the version byte
• Version byte - end of stream reached
• Cannot resolve schema for version: ${schemaVersion}
• Null key metadata buffer
• Failed to parse envelope encryption metadata

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/f025746d699e3c4c. Report an issue: GitHub.