apache/iceberg · error · UnsupportedOperationException

Bitmap decoding has not been implemented

Error message

Bitmap decoding has not been implemented

What it means

TrackedManifestFile wraps a manifest file for tracking/reporting purposes. When the underlying manifest carries deletion-vector bitmap data, the adapter returns a ManifestBitmap stub whose cardinality() method throws UnsupportedOperationException because bitmap decoding is not implemented. The throw signals an intentionally unimplemented capability, not a data corruption problem.

Source

Thrown at core/src/main/java/org/apache/iceberg/TrackedFileAdapters.java:526

      return file.keyMetadata();
    }

    @Override
    public Long firstRowId() {
      return file.tracking().firstRowId();
    }

    @Override
    public ManifestBitmap manifestDeletionVector() {
      ByteBuffer dv = file.manifestInfo().dv();
      if (dv == null) {
        return null;
      }

      return new ManifestBitmap() {
        @Override
        public int cardinality() {
          throw new UnsupportedOperationException("Bitmap decoding has not been implemented");
        }

        @Override
        public boolean isSet(int position) {
          throw new UnsupportedOperationException("Bitmap decoding has not been implemented");
        }

        @Override
        public ByteBuffer buffer() {
          return dv;
        }
      };
    }

    @Override
    public int formatVersion() {
      return file.formatVersion();
    }

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Do not call cardinality() on bitmap-backed ManifestBitmap instances; check the encoding type first and skip bitmap payloads.
2. Use buffer() to access the raw encoded bytes and decode the bitmap in application code if cardinality is required.
3. Upgrade to a Iceberg version where bitmap decoding is implemented, or contribute the implementation.

Example fix

// before
int deleted = bitmap.cardinality();

// after
ByteBuffer raw = bitmap.buffer(); // handle bitmap encoding in caller; cardinality() is unsupported

if (bitmapEncoding.isBitmap()) { /* skip cardinality, decode raw */ }

try { n = bitmap.cardinality(); } catch (UnsupportedOperationException e) { n = decodeCardinalityFromBuffer(bitmap.buffer()); }

When it happens

Trigger: Calling cardinality() on the ManifestBitmap returned by a TrackedManifestFile for a manifest whose deleted-rows payload is encoded as a bitmap rather than a deletion vector.

Common situations: Running table metrics/tracking tooling over tables that use bitmap-encoded deletions; code paths that assume all delete encodings are decoded DVs and call cardinality() unconditionally.

Related errors

• Staging snapshot %s on branch '%s' removes data files; equal
• Staging snapshot %s on branch '%s' contains a V2 positional
• %s doesn't implement copyWithStats
• %s doesn't implement validateFilesExist
• Can't retrieve values from an empty struct

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/4e9f8e036bcf1490. Report an issue: GitHub.